Technical Notes on Brick ConstructionBrick Industry Association 11490 Commerce Park Drive, Reston, Virginia 20191

1 REVISEDMarch 1992

ALL-WEATHER CONSTRUCTIONAbstract: This Technical Notes describes how extremes of cold and hot weather can influence brick masonry construction. Information on weather prediction necessary for construction planning is provided. Cold and hot weather are defined, and the reaction of clay brick masonry materials to these extreme conditions is described. Recommendations are provided for continuing construction in these severe exposure conditions.

Key Words: absorption, brick, climatology, cold weather, evaporation, freezing, grout, hot weather,meteorology, mortar.

INTRODUCTION Periods of cold and hot weather have a tremendous impact on the construction industry and the national economy. This is reflected in several ways. Cold weather can cause temporary delays and work stoppages on construction sites. Productivity and the quality of construction on job sites may be reduced if workers become too attentive to personal comfort during extremes in temperature. Proper material protection and handling can increase construction costs, although contractors and owners alike may benefit in the long run. Completed work not properly constructed during, or protected from, cold and sometimes hot weather may have to be removed and rebuilt. Investigations to evaluate the performance of suspect construction are an added expense which may be necessary. Owners and businessmen can suffer from lost rentals and business revenue when buildings are not completed on time. Furthermore, the seasonal influence on construction results in idle production facilities, large material inventories and high rates of unemployment during the winter months. Stopping work on a project due to extremes in weather conditions is not economically desirable. The purpose of this Technical Notes is to describe how masonry materials react to cold and hot weather conditions. It also describes provisions which should be made to ensure that construction does not decrease in quality and can continue without interruption. Although "normal", "cold", and "hot" are relative terms, normal, used in this Technical Notes, will be considered to be any temperature between 40 F and 90 F (4C and 32 C). Cold will be considered to be any temperature below 40F (4C), and hot any temperature above 90F (32C). WEATHER PREDICTION To successfully build during periods of abnormal weather conditions, designers and contractors must have advance knowledge of local meteorological conditions as

Examples of Climatic Data Available FIG. 1

well as knowledge of historic climatological information for a given area. Meteorology may be defined as current state atmospheric conditions, while climatology may be defined as the historic record of the averages and extremes of weather representative of an area. When in the planning stages for a project, designers are usually concerned with climatological data such as the average and extreme daytime and nighttime temperatures or average wind velocity for use in designing mechanical or

structural systems. Contractors, however, are more concerned with meteorological conditions during construction, such as hourly temperatures and mean daily temperature, as well as the predicted temperatures and wind velocities for the next few days. Mean daily temperature is determined by adding together the maximum temperature for each day (24 hours, midnight to midnight) and the minimum temperature for the same day and dividing by two. Ambient temperature as used in this Technical Notes is the outdoor temperature at the time considered. Meteorological information can be obtained from the National Weather Service, a branch of the National Oceanographic and Atmospheric Administration (NOAA). The National Weather Service has information centers located at major airports in cities throughout the country. These centers provide current weather information and regularly scheduled weather forecasts for the region under consideration. Climatological information can be obtained from the National Climatic Data Center, also a branch of NOAA. The National Climatic Data Center usually provides climatic information in the form of maps as shown in Figure 1. These maps contain daily, monthly and annual data for a region and may be obtained for a nominal fee by contacting the Center [5]. EFFECTS OF COLD WEATHER Cold weather during masonry construction affects the materials and labor used. Successful construction will consider both in the planning, scheduling and set up of the masonry work. In addition to anticipating the specific weather conditions, the contractor must determine what the probable effects of the weather will be on the materials and the workers, how to protect materials and workers, how to store the materials, and what procedures should be used to meet the requirements specified in the construction documents. In the United States, all model building codes have requirements relating to the construction of masonry during cold weather. While not identical, each of the building codes have similar general requirements regarding material protection, heating of materials, use of frozen materials and protection of completed work. Masonry Units Masonry units are the material in masonry construction least affected by below-normal temperatures. The physical properties of masonry units are essentially the same in cold weather except that a cold unit will have a slightly smaller volume than one at normal temperatures. However, the absorption characteristics of the masonry unit and its temperature contribute to the rate of freezing of masonry during cold weather. Under normal conditions of construction, using masonry units with initial rates of absorption (IRA) less than or equal to 30 g/min/30 in. (30 g/min/194 cm ) at the time of laying improves the bond between the brick and mortar which leads to increased moisture resistance of the wall assembly. In cold weather, brick having an initial rate of absorption of 25 g to 30 g/min/30 in. (25 g to 30 g/min/194 cm ) may be desirable.22 2 2 2

Using brick with a higher IRA reduces the risk of freezing by more rapidly absorbing water from the mortar or grout. If a brick with a low IRA is used, then the water content of the mortar should be the minimum necessary for workability. If suction or other measures reduce the water content to less than 6 percent of the total mortar volume prior to freezing, the mortar will not experience disruptive expansive forces upon freezing. Further, signifi cant reductions in transverse or compressive strength of the masonry assemblage will not occur. The temperature of the masonry unit also contributes to the rate of freezing of masonry. A cold unit will more rapidly withdraw the heat of hydration from the mortar and thus increase the rate of freezing. Masonry units preheated prior to laying minimize cold weather effects on the hydration process of the mortar by maintaining the heat within the mortar. Masonry units should be heated to a temperature of approximately 40F (4C) prior to laying when ambient temperatures are below 20F ( -7C). Heating units to temperatures above 40F (4C) is seldom necessary. It may be advantageous to heat units even when ambient temperatures are above 20F ( -7C). Preheated units will exhibit the same absorption characteristics as units laid during normal weather conditions. Units which are frozen should be thawed and dried completely before use. Frozen masonry should not be built upon. Completed masonry which is frozen may be moistened after thawing to reactivate the hydration process and continue to develop strength [7,10]. Mortar Mortar mixed with cold materials have properties quite different from those at normal temperatures. Cold weather retards the hydration of the cement in the mortar mix. Mortar mixed during cold weather often has lower water content, increased air content, and reduced early strength compared with those mixed during normal temperatures. For these reasons, mortar is often mixed with heated materials to produce performance characteristics associated with mortar mixed at normal temperatures, or with admixtures which may improve the early strength and plasticity of the mix. Water, sand, or both may be heated for use in mortar. Heating prepackaged materials such as portland cement and hydrated lime can be difficult. Specific recommendations are a function of temperature and are found in later sections of this Technical Notes. Mortar materials and the proportion of ingredients, within the permissible ranges, can also be modified for cold weather conditions. A higher sand content provides a stiffer mortar which will better support the weight of subsequently laid masonry. A lower lime content will allow the water content of the mortar to decrease more rapidly, just as a brick with a higher IRA. High-early-strength (Type III) portland cement may be used to increase the rate of early strength gain. Admixtures, although not recommended, may be used to accelerate the rate of set. Freezing of the mortar should be avoided in all cases. Mortar which freezes is not as weather-resistant or as watertight as mortar that has not been frozen [6]. Furthermore, significant reductions in compressive and

bond strength may occur. Mortar having a water content over 6 to 8 percent of the total volume will experience disruptive expansive forces if frozen due to the increase in volume of water when it is converted to ice. Thus, the bond between the unit and the mortar may be damaged or destroyed. Mortar in newly completed masonry should be protected from freezing. Specific requirements are found in Table 1. Grout Grout, although made from similar materials, should not be confused with concrete. Typically smaller aggregate is used in grout for easier placement and consolidation. Concrete uses a minimum amount of water, whereas the water-cement ratio for grout is high, because grout is placed in absorptive molds of brick. Furthermore, high water content is necessary in grout for ease of flow, but it greatly increases the amount of volumetric expansion which can occur upon freezing. Thus grout, like mortar, should be mixed with heated materials to prevent the damaging effects of freezing. High-early-strength (Type III) portland cement may be used to increase the rate of early strength gain of the grout. Admixtures may also be used, but protection of the grouted masonry is still required. MATERIALS IN COLD WEATHER CONSTRUCTION Protection Although the temperature of the materials used in masonry construction is one of the factors which should be adjusted for cold weather construction, adjustments in construction practices may also be necessary. ACI 530.1/ ASCE 6/TMS 602 , Specifications for Masonry Structures, addresses material heating as well as requirements for protection of masonry constructed in cold weather [3]. Protection is one of the most necessary adjustments to make in construction practices. Construction materials should be carefully covered to remain dry. ACI 530.1/ASCE 6/TMS 602 requires protection such as the use of insulating blankets and forced air heaters. However, protection may also include special light-weight, warm work clothes worn by laborers or standard construction equipment adapted to unique cold weather protection uses. This approach is common in northern Europe where cold weather may last up to six months. All masonry materials should be kept dry and free from ice and snow by covering with tarpaulins or clear polyethylene sheets. Sand and masonry units should be covered and stored on raised platforms to avoid contact with the ground. Careless material storage increases the cost of laying masonry because removal of ice and snow and thawing of masonry units are necessary before construction may begin. Partially completed or exposed walls should be covered at the end of each day's work with a weighted tarpaulin which extends a minimum of 2 ft (1 m) down each side of the wall to prevent contamination by water, ice, or snow (Fig. 2).

TABLE 1 Requirements for Brick Masonry Construction in Cold Weather

Temperature (see note)

Construction Requirements

Protection Requirements

100F-40F (38C-4C)

Normal procedures.

Cover walls with plastic or canvas at end of work day to prevent water from entering masonry.

40F-32F (4C-0C)

Heat mixing water or sand to produce mortar between 40F120F (4C-49C).

Completely cover newly constructed masonry with a weather resistant membrane for 48 hr after construction. Completely cover newly constructed masonry with a weather resistant membrane for 48 hr after construction.

32F-25F (0C- -4C)

Heat mixing water and sand to produce mortar between 40F120F (4F-49C). Heat grout materials so grout is placed at a temperature between 40F-120F (4C49C). Maintain mortar and grout above freezing until used in masonry. Heat mixing water and sand to produce mortar between 40F120F (4C-49C). Heat grout materials so grout is placed between 40F-120F (4C-49C). Maintain mortar and grout above freezing. Heat masonry units to 40F (4C) if grouting. Use heat sources on both sides of walls under construction.

25F-20F (-4C- -7C)

Completely cover newly constructed masonry with insulating blankets or equal protection for 48 hr. to prevent freezing. Install wind breaks when wind velocity exceeds 15 mph (6.7 m/s).

20F and Below Heat mixing water (-7C and Below) and sand to produce

Provide enclosure and heat to maintain temper atures above 32F (0C) mortar between within the enclosure for 40F-120F (4C48 hr after construction. 49C). Heat grout materials so grout is Heat may be provided by placed between 40F- electric heating blankets, infrared heat lamps or 120F (4C-49C). Heat masonry units to other approved methods. 40F (4C). Use heat sources on both sides of walls under construction. Provide enclosure and heat to maintain temperatures above 32F (0C) within the enclosure.

Note: Construction requirements, while work is in progress, are based on ambient temperatures. Protection requirements, after masonry is placed, are based on mean daily temperatures.

3

Brick Noise Barrier Wall with Cold Weather Protection FIG. 2

Enclosures in Place FIG. 3

Workers should also be protected from the cold weather to maintain their productivity. Recommended protection will vary with weather conditions from warmer clothes to complete enclosure of the work site. Masons may work in the open with forced air heaters as a heat source at mean daily temperatures no less than 20 F ( -7 C). Heated enclosures should be provided at temperatures below 20F ( -7C). By providing wind breaks or temporary shelters, workers can remain productive at outside temperatures well below freezing. If a shelter or enclosure is used both the workers and the materials benefit from a warmer environment. The masons' comfort and productivity are improved, and the materials need less preparation prior to laying (i.e. heating). There are many types of equipment which are available as sources of heat for cold weather construction. The type selected will depend upon availability of equipment, fuel source and economics, size of project and severity of exposure. Salamanders are widely used as a source of heat on scaffolds. Commercial electric blankets may be used to cover walls during the curing period. When complete enclosure of the work area is provided, space heaters are recommended. The enclosure should allow circulation of warm air on both sides of the masonry wall. Contractors have used several different methods for complete and partial enclosures of buildings. Large tents, temporary wood structures covered with clear plastic, and shelters built of prefabricated panels covered with clear plastic sheets are examples of complete enclosures (Figs. 3 and 4). Partial enclosures often consist of enclosed swinging scaffolds which may be moved from floor to floor when necessary (Figs. 5 and 6). Mortar and Grout Admixtures Accelerators. Accelerators are admixtures used to speed the setting time of mortar and grout. By increasing the rate of hydration of the cement, accelerators increase the rate of early strength gain. The most common accelerators are inorganic salts such as calcium chloride, calcium nitrate, soluble carbonates and some organic compounds. Any accelerator should be evaluated for deleterious effects on masonry strength and materials. Admixtures must not contribute to staining or efflorescence or cause4

Interior of Enclosure FIG. 4

corrosion of metal accessories used in construction of the masonry. Indiscriminate use of accelerators can adversely affect the in-place performance of the completed masonry. Accelerators alone are not suggested treatment for cold weather construction problems. Mortar and grout containing accelerators must still be protected from freezing. Calcium chloride, while highly effective as an accelerator and widely used in the past, causes corrosion of metals used in masonry due to the chloride content. For this

Antifreeze. An antifreeze lowers the freezing point of the substance to which it is added. Most commercial mortar "antifreeze" admixtures do not do this, but are instead accelerators. However, some true antifreeze admixtures are available. These admixtures are alcohols or combinations of salts. If used in the quantities required to be effective, significant reductions in mortar compressive and bond strengths usually result. For this reason, use of antifreeze compounds is not recommended. Heating In freezing weather, ice may be present in mixing water and moisture in the sand may turn to ice. Ice in the mixing water must be melted before it can be added to the mixer. Sand which contains frozen particles or frost cannot be used. It must first be thawed by heating in an appropriate manner. Further heating may also be beneficial. As stated earlier, both water and sand used in the mortar and grout may be heated to provide proper temperatures for construction. Water is the easiest method to heat. It is also the best material to heat because of its high specific heat. Sand may also be heated. This may be done by placing an electric heating pad on top of the sandpile and covering with a weather-resistant tarpaulin (Fig. 7). The electric pad can safely heat the sand overnight without exceeding a temperature of 100F (38 C). A more labor intensive method of heating the sand is to place the sand over a heated pipe or to pile the sand around a horizontal metal culvert or smoke stack section, in which a slow fire is built (Fig. 8). Other methods for heating sand involve the use of a steam lance or other steam heaters. Careful attention to the fire or other heat source and the sand is required. Sand should be heated slowly to avoid scorching. In an alternate approach, an electric rod can be used to heat mixing water and sand simultaneously. The electric heating rod is placed in a drum of water in the center of a sandpile. The rod heats the water over several hours. The sand surrounding the drum slowly absorbs heat from the drum and insulates the drum from further heat losses. Materials heated for use in mortar should have a minimum temperature of 70F (21C) and a maximum temperature of 160F (71C) to avoid flash set. Scorched sand (with a reddish cast) must not be used in mortar. In cold weather, mortar should be mixed in smaller amounts so it can be used before it cools. In any case, mortar must be used within 2 1/2 hours from the time of initial mixing. After combining all ingredients, the temperature of the mortar should be between 40F and 120F (4 C to 49C). Mortar temperatures over 120F (49C) may lead to flash set, resulting in lower compressive strength and reduced bond strength. Once a mortar temperature is selected, steps should be taken to mix successive batches to the same temperature. Mortar may be placed on electrically heated mortar boards to help maintain proper temperature. However, use caution to avoid excessive drying of the mortar with the heater. Grout should be placed at a minimum temperature of 40F (4C) and a maximum temperature of 120F (49C)5

Scaffold Enclosure FIG. 5

Tubular Scaffold Enclosure FIG. 6

reason, chlorides should not be used in mortar or grout in contact with metals (i.e. ties, anchors and reinforcement). Also, the incidence of efflorescence may be increased when excessive salts are present. If a chloride accelerator is used, it is recommended that it be limited to amounts not to exceed two percent of the weight of Portland used in the mortar mix or one percent of the weight of masonry cement. Calcium nitrite and calcium nitrate are inorganic nonchloride compounds also used as accelerators. These compounds require higher dosage by weight and are more costly than calcium chloride, but will not corrode metals or contribute to efflorescence.

be incorporated in the specifications of the project where applicable. 1. Protect masonry units, cementitious materials and sand so that they are not contaminated by rain, snow or ground water. 2. Cover tops of masonry at all times when work is not in progress. Cover shall extend a minimum of 2 ft (1 m) down the masonry, and shall be securely held in place. 3. Units with higher initial rates of absorption (up to 40 g/min/30 in. (40 g/min/194 cm )) may be used to resist mortar freezing. However, units with suctions inHeating of a Sandpile with an Electric Blanket FIG. 72 2

within 1 1/2 hours of mixing. As with mortar, water or

Heating of a Sandpile with a Metal Pipe FIG. 8

aggregate may be heated to produce a heated mixture. Water temperature should not exceed 160F (71C). The sand may be heated following recommendations for heating sand used in mortar. Masonry receiving grout should have a minimum temperature of 40F (4C). COLD WEATHER CONSTRUCTION RECOMMENDATIONS Special Precautions There are two reasons why masonry should never be placed on a snow or ice-covered base or bed. There is danger of movement when the base thaws, and bond cannot be developed between the mortar bed and frozen supporting surfaces. If the walls are properly covered when work is halted, ice or snow removal from walls should not be necessary. However, in the event that the covering is displaced, the top course may be thawed with steam or a portable blowtorch, carefully applied. The heat should be sustained long enough to thoroughly dry out the masonry. If portions of the masonry are frozen or damaged, defective parts should be replaced before progressing with new work. General Requirements--Cold Weather The following items are suggested in addition to the construction and protection requirements for cold weather masonry construction found in Table 1. These items can6

excess of 30 g/min/30 in. (30 g/min/194 cm ) shall be sprinkled, but not saturated, with heated water just prior to laying. Water temperature shall be above 70F (21C) when units are above 32F (0 C). If units are 32F (0C) or below, water temperature shall be above 120F (49C). 4. Use a mortar with a higher sand content and a lower water retention, especially with brick units having a low IRA. If Type III portland cement is used, the protection period listed in Table 1 may be reduced from 48 to 24 hours. 5. Heat sand and water used in mortar and grout mixtures to a minimum temperature of 70F (21C) and a maximum temperature of 160F (71C). Keep mortar temperature less than 120F (49C) to avoid flash set. 6. Maintain temperature of masonry units above 20F (-7C) when laid. 7. Place grout at a minimum temperature of 40F (4C) and a maximum temperature of 120F (49C). Maintain masonry receiving grout above 40F (4C). Maintain grouted masonry above 32F (0C) for 48 hours following placement of grout. EFFECTS OF HOT WEATHER Periods of hot weather may also adversely affect the construction of masonry. The contractor must take measures to ensure that the quality of masonry construction does not suffer from high temperatures. While hot weather has been defined to be temperatures above 90F (32C), temperature, wind speed, relative humidity and solar radiation all influence the absorption of masonry units, the rate of set, and the drying rate of mortar. The primary concern in controlling these properties in hot weather is evaporation of water from the mortar. If sufficient water is not present, bond between the brick and mortar will be sacrificed. The effects of high temperature and high humidity are not as damaging to the performance of the masonry as are low temperatures and low humidity. The increased rate of hydration of the cement and favorable curing conditions in hot, humid weather will help develop masonry strength if sufficient water is present at the time of construction. Temperature of the materials may be the easiest factor to adjust to produce performance characteristics associated with construction at normal temperatures. Adjustments in construction practices further aid the con-

2

2

struction of quality masonry in hot weather conditions. ACI 530.1/ASCE 6/TMS 602 specifies construction methods to produce quality masonry in hot weather conditions. Masonry Units Masonry units are the material in masonry construction least affected by hot weather. However, the interaction between the masonry units and the mortar or grout is critical. Warmer units will absorb more water from the mortar. In hot weather conditions this is usually not a problem unless high suction brick are used (IRA over 30 g/min/30 in. (30 g/min/194 cm )). If high suction brick are used, they should be properly wetted prior to laying. Wetting may take place immediately before laying the units, but the preferred method is to wet the whole pallet 3 to 24 hours before use. The brick must be surface dry at the time of laying and should have an IRA less than 30 g/min/30 in. (30 g/min/194 cm ). Lower bond strength results if not enough water is present in the mortar when the units are laid. Thus, lower absorption units may be desirable because they allow more complete hydration of the mortar. Mortar Mortar in hot weather will tend to lose its plasticity rapidly due to evaporation of the water from the mix and the increased rate of hydration of the cement. The use of admixtures to increase plasticity is not recommended unless their full effect on the mortar is known. Mortar with a high lime content and high water retention should be used. Retempering of the mortar should be permitted. Mortar mixed at high temperatures often has higher water content, lower air content, and a shorter board life than those mixed at normal temperatures. Temperature of the mortar should be maintained between 70 F and 120F (21C and 49C). Temperatures above 120F (49C) may cause flash set of the cement. Cold water may be used to help control the temperature of the mortar. Ice is highly effective in reducing the temperature of the mix water. When used, ice should be completely melted before combining the water with any other ingredients. In any case, mortar should be used within two hours of initial mixing. Grout Grout reacts to hot weather in a manner similar to mortar. Water more easily evaporates and thereby reduces the water-cement ratio. Grout requires a high slump, at least 8 in. (203 mm), for placement into the absorptive brick molds. Therefore, a high water-cement ratio should be maintained by reducing evaporation and initially mixing grout with adequate water. Furthermore, ACI 530.1/ASCE 6/TMS 602 specifies grout shall be used within 1 1/2 hours of mixing. As with mortar, ice may be used to lower the mix water temperature. HOT WEATHER CONSTRUCTION RECOMMENDATIONS Special Precautions During periods of hot weather the temperature of the materials should be controlled for best results. Storing brick and sand under cover of shade will help control heat72 2 2 2

gain of the materials. Sand should be stored on a raised platform and not in contact with a cover during the hot part of the day. This prevents ground moisture from rising, then condensing on the cover after temperatures cool down, thus contaminating the materials. When possible, shade should also be provided for laborers, whose productivity decreases with increasing temperature and humidity. Starting work earlier in the day and scheduling masonry construction to avoid the hot, mid-day periods can reduce the effects of high temperatures on laborers and materials. Adjusting masonry construction practices may effectively control hot weather problems. ACI 530.1/ASCE 6/TMS 602 limits the length that mortar may be spread to 4 ft (1.2 m) and requires masonry units to be placed within one minute of spreading the mortar. Wind breaks may prevent rapid drying of mortar during and after placement, and covering walls with a weather resistant membrane at the end of the work day will prevent rapid loss of moisture from the masonry assemblage. Wet curing or fog spraying may further improve masonry strength development during periods of high temperatures and low relative humidity. General Requirements--Hot Weather The following items are suggested in addition to the construction and protection requirements for hot weather masonry construction found in Table 2. These items can be incorporated in the specifications of the project where applicable. 1. Maintain temperature of mortar and grout between 70F and 120F (21C and 49C). 2. Cold water may be used when mixing mortar and grout. Ice used to lower the mix water temperature must be completely melted before adding the water to the other ingredients. 3. Masonry units with high suctions (IRA over 30 g/min/30 in. (30 g/min/194 cm )) should be properly wetted prior to use. Units with lower rates of absorption may be desirable. 4. Mortar with a high water retention is desirable. 5. Limit the spread of mortar beds to 4 ft (1.2 m) when temperatures are 100F (38C) or above, or 90F (32C) with a 8 mph (3.6 m/s) wind. 6. Place masonry units within one minute of spreading mortar. 7. Partially completed walls may be fog sprayed at the end of the work day to control moisture evaporation. SUMMARY This Technical Notes describes how masonry materials react to extremes in weather conditions. Construction requirements and protection requirements are recommended for construction in both cold and hot weather to ensure that construction can continue without a decrease in quality. Performance characteristics associated with materials mixed and constructed during normal temperatures can be achieved by following the appropriate construction and protection recommendations addressed in this Technical Notes. Tables 1 and 2 summarize these recommendations for coldNote: Construction requirements, while work is in progress, are based on ambient temperatures. Protection requirements, after masonry is placed, are based on2 2

TABLE 2 Requirements for Brick Masonry Construction in Hot Weather

Temperature (see note) Above 100F or 90F with 8 mph wind (above 38C or 32C with 3.6 m/s wind)

Construction Requirements Maintain mortar and grout at a temperature between 70F and 120F (21C-49C). Limit spread of mortar bed to 4 ft. Place units within 1 minute of spreading mortar.

Protection Requirements Partially or newly completed walls may be fog sprayed and/or covered with plastic or canvas to control moisture evaporation.

1970. 8. Standard Specification for Cold Weather Concreting (ACI 306.1), American Concrete Institute, 1990. 9. Suprenant, B.A., "Laying Masonry in Cold Weather", The Magazine of Masonry Construction, Vol. 1, No. 9, December 1988. 10. Van der Klugt, L.J.A.R., "Frost Damage to the Pointing and Laying Mortar of Clay Brick Masonry", TNO Building Construction and Research, Rijswijk, The Netherlands, 9th International Brick/Block Masonry Conference, October 1991.

100F-40F (38C-4C)

Normal procedures.

Cover walls with plastic or canvas at end of work day to prevent water from entering masonry.

mean daily temperatures.

and hot weather construction. The information and suggestions contained in this Technical Notes are based on the available data and the experience of the engineering staff of the Brick Institute of America. The information contained herein must be used in conjunction with good technical judgment and a basic understanding of the properties of brick masonry. Final decisions on the use of the information contained in this Technical Notes are not within the purview of the Brick Institute of America and must rest with the project architect, engineer and owner. REFERENCES 1. All-Weather Masonry Construction State of the Art Report, Technical Task Committee, International Masonry All-Weather Council, December 1968. 2. Brown, M.L., "Speeding Mortar Setting in Cold Weather", The Magazine of Masonry Construction, Vol. 2, No. 10 October 1989. 3. Building Code Requirements for Masonry Structures (ACI 530/ASCE 5/TMS 402) and Specifications for Masonry Structures (ACI 530.1/ASCE 6/TMS 602), American Concrete Institute, American Society of Civil Engineers, and The Masonry Society, 1992. 4. Cold Weather Concreting (ACI 306R), American Concrete Institute, 1988. 5. National Climatic Data Center, Federal Building, Asheville, NC 28801-2696, phone (704) 259-0682. 6. Randall, Jr., F.A., and Panarese, W.C., Concrete Masonry Handbook, Portland Cement Association, 1991. 7. Recommended Practices & Guide Specifications for Cold Weather Masonry Construction, International Masonry Industry All-Weather Council, December8

Technical Notes on Brick ConstructionBrick Industry Association 11490 Commerce Park Drive, Reston, Virginia 20191

2 REVISEDReissued* September 1988

GLOSSARY OF TERMS RELATING TO BRICK MASONRYABSORPTION: The weight of water a brick unit absorbs, when immersed in either cold or boiling water for a stated length of time. Expressed as a percentage of the weight of the dry unit. See ASTM Specification C 67. ADMIXTURES: Materials added to mortar to impart special properties to the mortar. ANCHOR: A piece or assemblage, usually metal, used to attach building parts (e.g., plates, joists, trusses, etc.) to masonry or masonry materials. ANSI: American National Standards Institute. ARCH: A curved compressive structural member, spanning openings or recesses; also built flat. Back Arch: A concealed arch carrying the backing of a wall where the exterior facing is carried by a lintel. Jack Arch: One having horizontal or nearly horizontal upper and lower surfaces. Also called flat or straight arch. Major Arch: Arch with spans greater than 6 ft and equivalent to uniform loads greater than 1000 lb. per ft. Typically known as Tudor arch, semicircular arch, Gothic arch or parabolic arch. Has rise to span ratio greater than 0.15. Minor Arch: Arch with maximum span of 6 ft and loads not exceeding 1000 lb. per ft. Typically known as jack arch, segmental arch or multicentered arch. Has rise to span ratio less than or equal to 0.15. Relieving Arch: One built over a lintel, flat arch, or smaller arch to divert loads, thus relieving the lower member from excessive loading. Also known as discharging or safety arch. Trimmer Arch: An arch, usually a low rise arch of brick, used for supporting a fireplace hearth. ASHLAR MASONRY: Masonry composed of rectangular units of burned clay or shale, or stone, generally larger in size than brick and properly bonded, having sawed, dressed or squared beds, and joints laid in mortar. Often the unit size varies to provide a random pattern, random ashlar. ASHRAE: American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. ASTM: American Society for Testing and Materials. BACK FILLING: 1. Rough masonry built behind a facing or between two faces. 2. Filling over the extrados of an arch. 3. Brickwork in spaces between structural timbers, sometimes called brick nogging. BACKUP: That part of a masonry wall behind the exterior facing. BAT: A piece of brick. BATTER: Recessing or sloping masonry back in successive courses; the opposite of corbel. BED JOINT: The horizontal layer of mortar on which a masonry unit is laid. BELT COURSE: A narrow horizontal course of masonry, sometimes slightly projected such as window sills which are made continuous. Sometimes called string course or sill course. BLOCKING: A method of bonding two adjoining or intersecting walls, not built at the same time, by means of offsets whose vertical dimensions are not less than 8 in. BOND: 1. Tying various parts of a masonry wall by lapping units one over another or by connecting with metal ties. 2. Patterns formed by exposed faces of units. 3. Adhesion between mortar or grout and masonry units or reinforcement. BOND BEAM: Course or courses of a masonry wall grouted and usually reinforced in the horizontal direction. Serves as horizontal tie of wall, bearing course for structural members or as a flexural member itself. BOND COURSE: The course consisting of units which overlap more than one wythe of masonry. BONDER: A bonding unit. See Header.*Originally published in Jan/Feb 1975, this Technical Notes has been reviewed and reissued.

BREAKING JOINTS: Any arrangement of masonry units which prevents continuous vertical joints from occurring in adjacent courses. BRICK: A solid masonry unit of clay or shale, formed into a rectangular prism while plastic and burned or fired in a kiln. Acid-Resistant Brick: Brick suitable for use in contact with chemicals, usually in conjunction with acid-resistant mortars. Adobe Brick: Large roughly-molded, sun-dried clay brick of varying size. Angle Brick: Any brick shaped to an oblique angle to fit a salient corner. Arch Brick: 1. Wedge-shaped brick for special use in an arch. 2. Extremely hardburned brick from an arch of a scove kiln. Building Brick: Brick for building purposes not especially treated for texture or color. Formerly called common brick. See ASTM Specification C 62. Clinker Brick: A very hard-burned brick whose shape is distorted or bloated due to nearly complete vitrification. Common Brick: See Building Brick. Dry-Press Brick: Brick formed in molds under high pressures from relatively dry clay (5 to 7 percent moisture content). Economy Brick: Brick whose nominal dimensions are 4 by 4 by 8 in. Engineered Brick: Brick whose nominal dimensions are 4 by 3.2 by 8 in. Facing Brick: Brick made especially for facing purposes, often treated to produce surface texture. They are made of selected clays, or treated, to produce desired color. See ASTM Specification C 216. Fire Brick: Brick made of refractory ceramic material which will resist high temperatures. Floor Brick: Smooth dense brick, highly resistant to abrasion, used as finished floor surfaces. See ASTM Specification C 410. Gauged Brick: 1. Brick which have been ground or otherwise produced to accurate dimensions. 2. A tapered arch brick. Hollow Brick: A masonry unit of clay or shale whose net cross-sectional area in any plane parallel to the bearing surface is not less than 60 percent of its gross crosssectional area measured in the same plane. See ASTM Specification C 652.

Jumbo Brick: A generic term indicating a brick larger in size than the standard. Some producers use this term to describe oversize brick of specific dimensions manufactured by them. Norman Brick: A brick whose nominal dimensions are 4 by 2 2/3 by 12 in. Paving Brick: Vitrified brick especially suitable for use in pavements where resistance to abrasion is important. See ASTM Specification C 7. Roman Brick: Brick whose nominal dimensions are 4 by 2 by 12 in. Salmon Brick: Generic term for under-burned brick which are more porous, slightly larger, and lighter colored than hardburned brick. Usually pinkish-orange color. "SCR Brick (Reg U.S. Pat Off., SCPI (BIA)): See SCR (Reg U.S. Pat. Off., SCPI (BIA)). Sewer Brick: Low absorption, abrasive-resistant brick intended for use in drainage structures. See ASTM Specification C 32. Soft-Mud Brick: Brick produced by molding relatively wet clay (20 to 30 percent moisture). Often a hand process. When insides of molds are sanded to prevent sticking of clay, the product is sand-struck brick. When molds are wetted to prevent sticking, the product is water-struck brick. Stiff-Mud Brick: Brick produced by extruding a stiff but plastic clay (12 to 15 percent moisture) through a die. BRICK AND BRICK: A method of laying brick so that units touch each other with only enough mortar to fill surface irregularities. BRICK GRADE: Designation for durability of the unit expressed as SW for severe weathering, MW for moderate weathering, or NW for negligible weathering. See ASTM Specifications C 216, C 62 and C 652. BRICK TYPE: Designation for facing brick which controls tolerance, chippage and distortion. Expressed as FBS, FBX and FBA for solid brick, and HBS, HBX, HBA and HBB for hollow brick. See ASTM Specifications C 216 and C 652. BUTTERING: Placing mortar on a masonry unit with a trowel. CAPACITY INSULATION: The ability of masonry to store heat as a result of its mass, density and specific heat. C/B RATIO: The ratio of the weight of water absorbed by a masonry unit during immersion in cold water to weight absorbed during immersion in boiling water. An indication of the probable resistance of brick to freezing and thawing. Also called saturation coefficient. See ASTM Specification C 67.

CENTERING: Temporary formwork for the support of masonry arches or lintels during construction. Also called center(s). CERAMIC COLOR GLAZE: An opaque colored glaze of satin or gloss finish obtained by spraying the clay body with a compound of metallic oxides, chemicals and clays. It is burned at high temperatures, fusing glaze to body making them inseparable. See ASTM Specification C 126. CHASE: A continuous recess built into a wall to receive pipes, ducts, etc. CLAY: A natural, mineral aggregate consist ing essentially of hydrous aluminum silicate; it is plastic when sufficiently wetted, rigid when dried and vitrified when fired to a sufficiently high temperature. CLAY MORTAR-MIX: Finely ground clay used as a plasticizer for masonry mortars. CLEAR CERAMIC GLAZE: Same as Ceramic Color Glaze except that it is translucent or slightly tinted, with a gloss finish. CLIP: A portion of a brick cut to length. CLOSER: The last masonry unit laid in a course. It may be whole or a portion of a unit. CLOSURE: Supplementary or short length units used at corners or jambs to maintain bond patterns. COLLAR JOINT: The vertical, longitudinal joint between wythes of masonry. COLUMN: A vertical member whose horizontal dimension measured at right angles to the thickness does not exceed three times its thickness. COPING: The material or masonry units forming a cap or finish on top of a wall, pier, pilaster, chimney, etc. It protects masonry below from penetration of water from above. CORBEL: A shelf or ledge formed by projecting successive courses of masonry out from the face of the wall. COURSE: One of the continuous horizontal layers of units, bonded with mortar in masonry. CULLS: Masonry units which do not meet the standards or specifications and have been rejected. DAMP COURSE: A course or layer of impervious material which prevents capillary entrance of moisture from the ground or a lower course. Often called damp check.2

DAMPPROOFING: Prevention of moisture penetration by capillary action. DOG'S TOOTH: Brick laid with their cor ners projecting from the wall face. DRIP: A projecting piece of material, shaped to throw off water and prevent its running down the face of wall or other surface. EBM: See Engineered Brick Masonry. ECCENTRICITY: The normal distance between the centroidal axis of a member and the parallel resultant load. e1/e2: Ratio of virtual eccentricities occurring at the ends of a column or wall under design. The absolute value is always less than or equal to 1.0. EFFECTIVE HEIGHT: The height of a member to be assumed for calculating the slenderness ratio. EFFECTIVE THICKNESS: The thickness of a member to be assumed for calculating the slenderness ratio. EFFLORESCENCE: A powder or stain sometimes found on the surface of masonry, resulting from deposition of water-soluble salts. ENGINEERED BRICK MASONRY: Masonry in which design is based on a rational structural analysis. FACE: 1. The exposed surface of a wall or masonry unit. 2. The surface of a unit designed to be exposed in the finished masonry. FACING: Any material, forming a part of a wall, used as a finished surface. FIELD: The expanse of wall between openings, corners, etc., principally composed of stretchers. FILTER BLOCK: A hollow, vitrified clay masonry unit, sometimes salt-glazed, designed for trickling filter floors in sewage disposal plants. See ASTM Specification C 159. FIRE CLAY: A clay which is highly resistant to heat without deforming and used for making brick. FIRE RESISTIVE MATERIAL: See Noncombustible Material. FIREPROOFING: Any material or combination protecting structural members to increase their fire resistance.

FLASHING: 1. A thin impervious material placed in mortar joints and through air spaces in masonry to prevent water penetration and/or provide water drainage. 2. Manufacturing method to produce specific color tones. FROG: A depression in the bed surface of a brick. Sometimes called a panel. FURRING: A method of finishing the interior face of a masonry wall to provide space for insulation, prevent moisture transmit tance, or to provide a level surface for finishing. GROUNDS: Nailing strips placed in masonry walls as a means of attaching trim or furring. GROUT: Mixture of cementitious material and aggregate to which sufficient water is added to produce pouring consistency without segregation of the constituents. High-Lift Grouting: The technique of grouting masonry in lifts up to 12 ft. Low-Lift Grouting: The technique of grouting as the wall is constructed. HACKING: 1. The procedure of stacking brick in a kiln or on a kiln car. 2. Laying brick with the bottom edge set in from the plane surface of the wall. HARD-BURNED: Nearly vitrified clay products which have been fired at high temperatures. They have relatively low absorptions and high compressive strengths. HEAD JOINT: The vertical mortar joint between ends of masonry units. Often called cross joint. HEADER: A masonry unit which overlaps two or more adjacent wythes of masonry to tie them together. Often called bonder. Blind Header: A concealed brick header in the interior of a wall, not showing on the faces. Clipped Header: A bat placed to look like a header for purposes of establishing a pattern. Also called a false header. Flare Header: A header of darker color than the field of the wall. HEADING COURSE: A continuous bonding course of header brick. Also called header course. INITIAL RATE OF ABSORPTlON: The weight of water absorbed expressed in grams per 30 sq. in. of contact surface when a brick is partially immersed for one minute. Also called suction. See ASTM Specification C 67. IRA: See Initial Rate of Absorption.

KILN: A furnace oven or heated enclosure used for burning or firing brick or other clay material. Kiln Run: Brick from one kiln which have not been sorted or graded for size or color variation. KING CLOSER: A brick cut diagonally to have one 2 in. end and one full width end. LATERAL SUPPORT: Means whereby walls are braced either vertically or horizontally by columns, pilasters, cross walls, beams, floors, roofs, etc. LEAD: The section of a wall built up and racked back on successive courses. A line is attached to leads as a guide for constructing a wall between them. LIME, HYDRATED: Quicklime to which sufficient water has been added to convert the oxides to hydroxides. LIME PUTTY: Hydrated lime in plastic form ready for addition to mortar. LINTEL: A beam placed over an opening in a wall. MASONRY: Brick, stone, concrete, etc., or masonry combinations thereof, bonded with mortar. MASONRY CEMENT: A mill-mixed cementitious material to which sand and water must be added. See ASTM C 91. MASONRY UNIT: Natural or manufactured building units of burned clay, concrete, stone, glass, gypsum, etc. Hollow Masonry Unit: One whose net cross-sectional area in any plane parallel to the bearing surface is less than 75 percent of the gross. Modular Masonry Unit: One whose nominal dimensions are based on the 4 in. module. Solid Masonry Unit: One whose net cross-sectional area in every plane parallel to the bearing surface is 75 percent or more of the gross. MORTAR: A plastic mixture of cementitious materials, fine aggregate and water. See ASTM Specifications C 270, C 476 or BIA M1-72. Fat Mortar: Mortar containing a high percentage of cementitious components. It is a sticky mortar which adheres to a trowel. High-Bond Mortar: Mortar which develops higher bond strengths with masonry units than normally developed with conventional mortar. Lean Mortar: Mortar which is deficient in cementitious components, it is usually harsh and difficult to spread.3

NOMINAL DIMENSION: A dimension greater than a specified masonry dimension by the thickness of a mortar joint, but not more than 1/2 in. NON-COMBUSTIBLE MATERIAL: Any material which will neither ignite nor actively support combustion in air at a temperature of 1200 F when exposed to fire. OVERHAND WORK: Laying brick from inside a wall by men standing on a floor or on a scaffold. PARGETING: The process of applying a coat of cement mortar to masonry. Often spelled and/or pronounced parging. PARTITION: An interior wall, one story or less in height. PICK AND DIP: A method of laying brick whereby the bricklayer simultaneously picks up a brick with one hand and, with the other hand, enough mortar on a trowel to lay the brick. Sometimes called the Eastern or New England method. PIER: An isolated column of masonry. PILASTER: A wall portion projecting from either or both wall faces and serving as a vertical column and/or beam. PLUMB RULE: This is a combination plumb rule and level. It is used in a horizontal position as a level and in a vertical position as a plumb rule. They are made in lengths of 42 and 48 in., and short lengths from 12 to 24 in. POINTING: Troweling mortar into a joint after masonry units are laid. PREFABRICATED BRICK MASONRY: Masonry construction fabricated in a location other than its final inservice location in the structure. Also known as preassembled, panelized and sectionalized brick masonry. PRISM: A small masonry assemblage made with masonry units and mortar. Primarily used to predict the strength of full scale masonry members. QUEEN CLOSER: A cut brick having a nominal 2 in. horizontal face dimension. QUOIN: A projecting right angle masonry corner. RACKING: A method entailing stepping back successive courses of masonry. RAGGLE: A groove in a joint or special unit to receive roofing or flashing.

RBM: Reinforced brick masonry REINFORCED MASONRY: Masonry units, reinforcing steel, grout and/or mortar combined to act together in resisting forces. RETURN: Any surface turned back from the face of a principal surface. REVEAL: That portion of a jamb or recess which is visible from the face of a wall. ROWLOCK: A brick laid on its face edge so that the normal bedding area is visible in the wall face. Frequently spelled rolok. SALT GLAZE: A gloss finish obtained by thermochemical reaction between silicates of clay and vapors of salt or chemicals. SATURATION COEFFICIENT: See C/B Ratio. SCR (Reg U.S. Pat Off., SCPI (BIA)): Structural Clay Research (trademark Of the Structural Clay Products Institute, BIA). "SCR acoustile" (Reg U.S. Pat Off., SCPI (BIA) Pat. No 3,001,6O2): A sideconstruction two-celled facing tile, having a perforated face backed with glass wool for acoustical purposes. "SCR brick" (Reg U.S. Pat Off., SCPI (BIA)): Brick whose nominal dimensions are 6 by 2 2/3 by 12 in. (Reg U.S. Pat Off., SCPI (BIA)): "SCR building panel" (Reg U S. Pat Off., SCPI (BIA) Pat. No. 3,248,836): Prefabricated, structural ceramic panels, approximately 2 1/2 in. thick. "SCR insulated cavity wall" (Reg U.S. Pat Off., SCPI (BIA)): Any cavity wall containing insulation which meets rigid criteria established by the Structural Clay Products Institute (BIA). "SCR masonry process" (Reg. U.S. Pat Off., SCPI (BIA)): A construction aid providing greater efficiency, better workman ship and increased production in masonry construction. It utilizes story poles, marked lines and adjustable scaffolding. SHALE: Clay which has been subjected to high pressures until it has hardened. SHOVED JOINTS: Vertical joints filled by shoving a brick against the next brick when it is being laid in a bed of mortar. SLENDERNESS RATIO: Ratio of the effective height of a member to its effective thickness. SLUSHED JOINTS: Vertical joints filled, after units are laid, by throwing" mortar in with the edge of a trowel. (Generally, not recommended.) SOAP: A masonry unit of normal face dimensions, having a nominal 2 in. thickness.

SOFFIT: The underside of a beam, lintel or arch. SOFT-BURNED: Clay products which have been fired at low temperature ranges, producing relatively high absorptions and low compressive strengths. SOLAR SCREEN: A perforated wall used as a sunshade. SOLDIER: A stretcher set on end with face showing on the wall surface. SPALL: A small fragment removed from the face of a masonry unit by a blow or by action of the elements. STACK: Any structure or part thereof which contains a flue or flues for the discharge of gases. STORY POLE: A marked pole for measur ing masonry coursing during construction. STRETCHER: A masonry unit laid with its greatest dimension horizontal and its face parallel to the wall face. STRINGING MORTAR: The procedure of spreading enough mortar on a bed to lay several masonry units. STRUCK JOINT: Any mortar joint which has been finished with a trowel. SUCTION: See Initial Rate of Absorption. TEMPER: To moisten and mix clay, plaster or mortar to a proper consistency. TIE: Any unit of material which connects masonry to masonry or other materials. See Wall Tie. TOOLING: Compressing and shaping the face of a mortar joint with a special tool other than a trowel. TOOTHING: Constructing the temporary end of a wall with the end stretcher of every alternate course projecting. Projecting units are toothers. TRADITIONAL MASONRY: Masonry in which design is based on empirical rules which control minimum thickness, lateral support requirements and height without a structural analysis. TUCK POINTING: The filling in with fresh mortar of cut-out or defective mortar joints in masonry. VENEER: A single wythe of masonry for facing purposes, not structurally bonded.

VIRTUAL ECCENTRICITY: The eccentricity of a resultant axial load required to produce axial and bending stresses equivalent to those produced by applied axial loads and moments. It is normally found by dividing the moment at a section by the summation of axial loads occurring at that section. VITRIFICATION: The condition resulting when kiln temperatures are sufficient to fuse grains and close pores of a clay product, making the mass impervious. WALL: A vertical member of a structure whose horizontal dimension measured at right angles to the thickness exceeds three times its thickness. Apron Wall: That part of a panel wall between window sill and wall support. Area Wall: 1. The masonry surrounding or partly surrounding an area. 2. The retaining wall around basement windows below grade. Bearing Wall: One which supports a vertical load in addition to its own weight. Cavity Wall: A wall built of masonry units so arranged as to provide a continuous air space within the wall (with or without insulating material), and in which the inner and outer wythes of the wall are tied together with metal ties. Composite Wall: A multiple-wythe wall in which at least one of the wythes is dissimilar to the other wythe or wythes with respect to type or grade of masonry unit or mortar Curtain Wall: An exterior non-loadbearing wall not wholly supported at each story. Such walls may be anchored to columns, spandrel beams, floors or bearing walls, but not necessarily built between structural elements. Dwarf Wall: A wall or partition which does not extend to the ceiling. Enclosure Wall: An exterior non-bearing wall in skeleton frame construction. It is anchored to columns, piers or floors, but not necessarily built between columns or piers nor wholly supported at each story. Exterior Wall: Any outside wall or vertical enclosure of a building other than a party wall. Faced Wall: A composite wall in which the masonry facing and backings are so bonded as to exert a common reaction under load. Fire Division Wall: Any wall which subdivides a building so as to resist the spread of fire. It is not necessarily continuous through all stories to and above the roof. Fire Wall: Any wall which subdivides a building to resist the spread of fire and which extends continuously from the foundation through the roof. Foundation Wall: That portion of a loadbearing wall below the level of the adjacent grade, or below first floor beams or joists.

4

Hollow Wall: A wall built of masonry units arranged to provide an air space within the wall. The separated facing and backing are bonded together with masonry units. Insulated Cavity Wall: See SCR insulated cavity wall. Loadbearing Wall: A wall which supports any vertical load in addition to its own weight. Non-Loadbearing Wall: A wall which supports no vertical load other than its own weight. Panel Wall: An exterior, non-loadbearing wall wholly supported at each story. Parapet Wall: That part of any wall entirely above the roof line. Party Wall: A wall used for joint service by adjoining buildings. Perforated Wall: One which contains a considerable number of relatively small openings. Often called pierced wall or screen wall. Shear Wall: A wall which resists hori zontal forces applied in the plane of the wall. Single Wythe Wall: A wall containing only one masonry unit in wall thickness. Solid Masonry Wall: A wall built of solid masonry units, laid contiguously, with joints between units completely filled with mortar or grout. Spandrel Wall: That part of a curtain wall above the top of a window in one story and below the sill of the window in the story above. Veneered Wall: A wall having a facing of masonry units or other weather-resisting non-combustible materials securely attached to the backing, but not so bonded as to intentionally exert common action under load. WALL PLATE: A horizontal member anchored to a masonry wall to which other structural elements may be attached. Also called head plate. WALL TIE: A bonder or metal piece which connects wythes of masonry to each other or in other materials. WALL TIE, CAVITY: A rigid, corrosionresistant metal tie which bonds two wythes of a cavity wall. It is usually steel, 3/16 in. in diameter and formed in a "Z" shape or a rectangle. WALL TIE, VENEER: A strip or piece of metal used to tie a facing veneer to the backing. WATER RETENTIVITY: That property of a mortar which prevents the rapid loss of water to masonry units of high suction. It prevents bleeding or water gain when mortar is in contact with relatively impervious units.

WATER TABLE: A projection of lower masonry on the outside of the wall slightly above the ground. Often a damp course is placed at the level of the water table to prevent upward penetration of ground water. WATERPROOFING: Prevention of moisture flow through masonry due to water pressure. WEEP HOLES: Openings placed in mortar joints of facing material at the level of flashing, to permit the escape of moisture. WITH INSPECTION: Masonry designed with the higher stresses allowed under EBM. Requires the establishing of procedures on the job to control mortar mix, workmanship and protection of masonry materials. WITHOUT INSPECTION: Masonry designed with the reduced stresses allowed under EBM. WYTHE: 1. Each continuous vertical section of masonry one unit in thickness. 2. The thickness of masonry separating flues in a chimney. Also called withe or tier.

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Technical Notes on Brick ConstructionBrick Industry Association 11490 Commerce Park Drive, Reston, Virginia 20191

3ADecember 1992

BRICK MASONRY MATERIAL PROPERTIESAbstract: Brick masonry has a long history of reliable structural performance. Standards for the structural design of masonry which are periodically updated such as the Build ing Code Requirements for Masonry Structures (ACI 530/ASCE 5/TMS 402) and the Specifi cations for Masonry Structures (ACI 530.1/ASCE 6/TMS 602) advance the efficiency of masonry elements with rational design criteria. However, design of masonry structural members begins with a thorough understanding of material properties. This Technical Notes is an aid for the design of brick and structural clay tile masonry structural members. Clay and shale units, mortar, grout, steel reinforcement and assemblage material properties are presented to simplify the design process.

Key Words: brick, grout, material properties, mortar, reinforcement, structural clay tile.

INTRODUCTION The Masonry Standards Joint Committee (MSJC) has developed the Building Code Requirements for Ma sonry Structures (ACI 530/ASCE 5/TMS 402) and the Specifications for Masonry Structures (ACI 530.1/ASCE 6/TMS 602). In this Technical Notes, these documents will be referred to as the MSJC Code and the MSJC Specifications, respectively. Their contents are reviewed in Technical Notes 3. The MSJC Code and Specifications are periodically revised by the MSJC and together provide design and construction requirements for masonry. The MSJC Code and Specifications apply to structural masonry assemblages of clay, concrete or stone units. This Technical Notes is a design aid for the MSJC Code and Specifications. It contains information on clay and shale units, mortar, grout, steel reinforcement and assemblage material properties. These are used in the initial stages of a structural design or analysis to determine applied stresses and allowable stresses. Material properties are explained to aid the designer in selection of materials and to provide a better understanding of the structural properties of the masonry assemblage based on the materials selected. CONSTITUENT MATERIAL PROPERTIES Because brick masonry is bonded into an integral mass by mortar and grout, it is considered to be a homogeneous construction. It is the behavior of the combination of materials that determines the performance of the masonry as a structural element. However, the performance of a structural masonry element is dependent upon the properties of the constituent materials and the interaction of the materials as an assemblage.

Therefore, it is important to first consider the properties of the constituent materials: clay and shale units, mortar, grout and steel reinforcement. This will be followed by a discussion of the behavior of their combination as an assemblage. Clay and Shale Masonry Units There are many variables in the manufacturing of clay and shale masonry units. Primary raw materials include surface clays, fire clays, shales or combinations of these. Units are formed by extrusion, molding or dry-pressing and are fired in a kiln at temperatures between 1800 oF and 2100oF (980 oC and 1150oC). These variables in manufacturing produce units with a wide range of colors, textures, sizes and physical properties. Clay and shale masonry units are most frequently selected as a construction material for their aesthetics and long-term performance. Consequently, material standards for clay and shale masonry units contain requirements to ensure that units meet a level of durability and visual and dimensional consistency. Clay and shale masonry units used in structural elements of building constructions are brick and structural clay tile. Material standards for brick and structural clay tile include: ASTM C 216 (facing brick), ASTM C 62 (building brick), ASTM C 652 (hollow brick), ASTM C 212 (structural clay facing tile) and ASTM C 34 (structural clay load-bearing tile). While brick and structural clay tile are both visually appealing and durable, they are also well-suited for many structural applications. This is primarily due to their variety of sizes and very high compressive strength. The material properties of brick and structural clay tile which have the most significant effect upon structural performance of the masonry are compres-

sive strength and those properties affecting bond between the unit and mortar, such as rate of water absorption and surface texture. Unit Compressive Stre n g t h . The compressive strength of brick or structural clay tile is an important material property for structural applications. In general, increasing the compressive strength of the unit will increase the masonry assemblage compressive strength and elastic modulus. However, brick and structural clay tile are frequently specified by material standard rather than by a particular minimum unit compressive strength. ASTM material standards for brick and structural clay tile require minimum compressive strengths to ensure durability, which may be as little as one-fifth the actual unit compressive strength. A recent Brick Institute of America survey of United States brick manufacturers resulted in a data base of unit properties [6]. A subsequent survey of structural clay tile manufacturers was conducted. The compressive strengths of brick and structural clay tile evaluated in these surveys are presented in Table 1. As is apparent, all types of brick and structural clay tile typically exhibit compressive strengths considerably greater than the ASTM minimum requirements. Compressive strength of brick and structural clay tile is determined in accordance with ASTM C 67 Method of Sampling and Testing Brick and Structural Clay Tile.TABLE 1 Brick and Structural Clay Tile Unit Compressive StrengthsStandard Mean Unit Deviation of Compressive Compressive Strength, Strength, psi (MPa) psi (MPa) Extruded Molded Fire clay Raw material1 Shale Other2 Hollow Structural clay tile3 brick3 Vertical coring Horizontal coring 11305 (77.9) 5293 (36.5) 15346(105.8) 11258 (77.6) 9169 (63.2) 6736 (46.4) 10057 (69.3) 5119 (35.3) 4464 (30.8) 1822 (12.6) 5065 (34.9) 3487 (24.0) 3988 (27.5) 2447 (16.9) 5578 (38.5) 2067 (14.3)

Cores or frogs provide a means of mechanical interlock. The bond strength of sanded surfaces is dependent upon the amount of sand on the surface, the sands adherence to the unit and the absorption rate of the unit at the time of laying. In practically all cases, mortar bonds best to a unit whose suction at the time of laying is less than 30 g/min/30 in. 2 (1.55 kg/min/m 2). Generally, molded units will exhibit a higher initial rate of absorption than extruded or dry-pressed units. Unit absorption at the time of laying is an alterable property of brick and structural clay tile. In accordance with the MSJC Specifications, units with initial rate of absorption in excess of 30 g/min/30 in.2 (1.55 kg/min/m2) should be wetted to reduce the rate of water absorption of the unit prior to laying. In addition, suction of very absorptive units may be accommodated by using highly water-retentive mortars. Mortar The material properties of mortar which influence the structural performance of masonry are compressive strength, bond strength and elasticity. Because the compressive strength of masonry mortar is less important than bond strength, workability and water retentivity, the latter properties should be given principal consideration in mortar selection. Mortar materials, properties and selection of masonry mortars are discussed in Technical Notes 8 Series. Mortar should be selected based on the design requirements and with due consideration of the MSJC Code and Specifications provisions affected by the mortar selected. Laboratory testing indicates that masonry constructed with portland cement-lime mortar exhibit greater flexural bond strength than masonry constructed with masonry cement mortar or air-entrained portland cement-lime mortar of the same Type. This behavior is reflected in the MSJC Code allowable flexural tensile stresses for unreinforced masonry, which are based on the mortar Type and mortar materials selected. In addition, masonry cement mortars may not be used in Seismic Zones 3 and 4. Other MSJC Code and Specifications provisions are the same for portland cement-lime mortars, masonry cement mortars and air-entrained portland cement-lime mortars of the same Type. These include the modulus of elasticity of the masonry, allowable compressive stresses for empirical design and the Unit Strength Method of verifying that the specified compressive strength of masonry is supplied. Following is a general description of the structural properties of each Type of mortar permitted by the MSJC Code and Specifications. Type N Mortar. Type N mortar is specifically recommended for chimneys, parapet walls and exterior walls subject to severe exposure. It is a medium bond and compressive strength mortar suitable for general use in exposed masonry above grade. Type N mortar 2

Unit Type

Forming method Solid brick

1 Extruded only. 2 Made from other materials or a combination of materials. 3 Based on gross area.

Unit Texture and Absorption. Unit texture and absorption are properties which affect the bond strength of the masonry assemblage. In general, mortar bonds better to roughened surfaces, such as wire cut surfaces, than to smooth surfaces, such as die skin surfaces.

may not be used in Seismic Zones 3 and 4. Type S Mortar. Type S mortar is recommended for use in reinforced masonry and unreinforced masonry where maximum flexural strength is required. It has a high compressive strength and has a high tensile bond strength with most brick units. Type M Mortar. Type M mortar is specifically recommended for masonry below grade and in contact with earth, such as foundation walls, retaining walls, sewers and manholes. It has high compressive strength and better durability in these environments than Type N or S mortars. For compliance with the MSJC Specifications, mortars should conform to the requirements of ASTM C 270 Specification for Mortar for Unit Masonry. Field sampling of mortar for quality control should follow the procedures given in ASTM C 780 Test Method for Preconstruction and Construction Evaluation of Mortars for Plain and Reinforced Unit Masonry. Test procedures for masonry mortars are covered in Technical Notes 39 Series. Grout Grout is used in brick masonry to fill cells of hollow units or spaces between wythes of solid unit masonry. Grout increases the compressive, shear and flexural strength of the masonry element and bonds steel reinforcement and masonry together. For compliance with the MSJC Specifications, grout which is used in brick or structural clay tile masonry should conform to the requirements of ASTM C 476 Specification for Grout for Masonry. Grout proportions of portland cement or blended cement, hydrated lime or lime putty, and coarse or fine aggregate are given in Table 2.TABLE 2 ASTM C 476 Grout Proportions by VolumePortland Hydrated Cement Lime or or Lime Blended Putty Cement

amount of water absorbed from grout by hollow clay units appears to be more dependent on the initial water content of the grout than the absorption properties of the unit [3]. Grouts with high initial water content exhibit more shrinkage than grouts with low initial water contents. Consequently, use of a non-shrink grout admixture is recommended to minimize the number of flaws and shrinkage cracks in the grout while still producing a grout slump of 8 to 11 in. (200 to 280 mm), unless otherwise specified. The MSJC Specifications require grout compressive strength to be at least equal to the specified compressive strength of masonry, f , but not less than 2,000 psi m (13.8 MPa) as determined by ASTM C 1019 Method of Sampling and Testing Grout. Test procedures for grout are explained in more detail in Technical Notes 39 Series. In general, the compressive strength of ASTM C 476 grout by proportions will be greater than 2,000 psi (13.8 MPa). Prediction of the compressive strength of grout which is proportioned in accordance with ASTM C 476 is difficult because of the many possible combinations of materials, types of materials and construction conditions. However, ASTM C 476 grout proportions produce a rich mix which is recommended to complement the high compressive strength of brick and structural clay tile.TABLE 3 Steel Reinforcement Material Properties1Minimum Yield Strength, ksi (MPa) 40 (276) 60 (414) 50 (345) 60 (414) 40 (276) 60 (414) 60 (414) 70 (483) 75 (517) Minimum Tensile Strength, ksi (MPa) 70 (483) 90 (620) 80 (552) 90 (620) 70 (483) 90 (620) 80 (552) 80 (552) 85 (586)

Type

ASTM Grade Specification or Type

A 615

40 60

A 616 Fine Aggregate1 Coarse Aggregate1 Bars A 617 2 1/4 to 3 times the sum of the volumes of the cementitious materials 2 1/4 to 3 times the sum of the volumes of the cementitious materials

50 60 40 60

Grout Type

A 706 None Wires A 496 1 to 2 times the sum of the volumes of the cementitious materials1From reference [5].

60 Smooth Deformed

Fine

1

0 to 1/10

A 82

Coarse

1

0 to 1/10

1Aggregate measured by volume in a damp, loose condition.

Steel Reinforcement Steel reinforcement for masonry construction consists of bars and wires. Reinforcing bars are used in masonry elements such as walls, columns, pilasters and beams. Wires are used in masonry bed joints to reinforce individual masonry wythes or to tie multiple wythes together. Bars and wires have approximately 3

The amount of mixing water and its migration from the grout to the brick or structural clay tile will determine the compressive strength of the grout and the amount of grout shrinkage. Tests indicate that the total

the same modulus of elasticity, which is stated in the MSJC Code as 29,000 ksi (200,000 MPa). In general, wires tend to achieve greater ultimate strength and behave in a more brittle manner than reinforcing bars. Common bar and wire sizes and their material properties are given in Table 3. As stated in the MSJC Specifications, steel reinforcement for masonry structural members should comply with one of the material standards given in Table 4.TABLE 4 ASTM Material Standards for Steel ReinforcementSteel Reinforcement Type Deformed bars Joint reinforcement Deformed wire Wire fabric Anchors, ties and accessories Stainless steel ASTM Specification A 615, A 616, A 617 or A 706 A 82 A 496 A 185 or A 497 A 36, A 366, A 185 or A 82 A 167-Type 304

ASSEMBLAGE MATERIAL PROPERTIES The properties of the constituent materials discussed previously combine to produce the brick or structural clay tile masonry assemblage properties. Following is a discussion of the material properties of the masonry assemblage. Compressive Strength Perhaps the single most important material property in the structural design of masonry is the compressive strength of the masonry assemblage. The specified compressive strength of the masonry assemblage, f , is m used to determine the allowable axial and flexural compressive stresses, shear stresses and anchor bolt loads given in the MSJC Code. The compressive strength of the masonry assemblage can be evaluated by the properties of each constituent material, termed in the MSJC Specifications the Unit Strength Method, or by testing the properties of the entire masonry assemblage, termed the Prism Testing Method. These methods are not to be used to establish design values; rather, they are used by the contractor to verify that the masonry achieves the specified compressive strength, f . m Unit Strength Method. A benefit of verifying compliance of the compressive strength of masonry by unit, mortar and grout properties is the elimination of prism testing. Each of the materials in the masonry assemblage must conform to ASTM material standards mentioned in previous sections of this Technical Notes. For 4

compliance with these material standards, the compressive strength of the unit and the proportions or properties of the mortar and grout must be evaluated. Not surprisingly, there have been attempts by numerous researchers to accurately correlate the assemblage compressive strength with unit, mortar and grout compressive strengths. Testing an assemblage of three materials produces a large scatter of compressive strengths covering all possible combinations of materials. Therefore, estimates of the masonry assemblage compressive strength based on unit, mortar and grout properties are necessarily conservative. The correlations provided in the MSJC Specifications, shown in Table 5, between unit compressive strength, mortar type and the masonry assemblage compressive strength represent a lower-bound to experimental data. In addition, the MSJC Specifications Unit Strength Method does not directly address variable grout strength, multiwythe construction or the influence of joint reinforcement on the compressive strength of the masonry assemblage. Consequently, compliance with the specified compressive strength of masonry by prism testing will always produce a more accurate and optimum use of brick or structural clay tile masonrys compressive strength than the Unit Strength Method. The conservative nature of Table 5 should not be overlooked by the designer. A comparison of the predicted assemblage compressive strength by the Unit Strength Method in the MSJC Specifications and a data base of actual brick masonry prism test results [1] reveals this conservatism. The average compressive strength of prisms of solid brick units was found to be about 1.7 times the masonry compressive strength predicted by Table 5. The average compressive strength of prisms of hollow units ungrouted and grouted was found to be 1.9 and 1.4 times the compressive strengths predicted by Table 5, respectively.TABLE 5 Unit Strength Method of fm Compliance in the MSJC Specifications1Net Area Unit Compressive Strength, psi (MPa) Type M or S mortar 2400(16.6) 4400(30.3) 6400(44.1) 8400(57.9) 10400(71.7) 12400(85.5) 14400(99.3) Type N mortar 3000 (20.7) 5500 (37.9) 8000 (55.2) 10500 (72.4) 13000 (89.7)

Net Area Assemblage Compressive Strength, psi (MPa)

1000 (6.9) 1500 (10.3) 2000 (13.8) 2500 (17.2) 3000 (20.7) 3500 (24.1) 4000 (27.6)

1 Linear interpolation is permitted.

Prism Test Method. Prism testing of brick or structural clay tile masonry provides a number of advantages over constituent material testing alone. The primary benefit of prism testing is a more accurate estimation of the compressive strength of the masonry assemblage. Another benefit of prism testing is that it provides a method of measuring the quality of workmanship throughout the course of a project. Low prism strengths may indicate mortar mixing error or poor quality grout. The MSJC Specifications permit testing of masonry prisms to show conformance with the specified compressive strength of masonry, f . In addition, the matem rial components must meet the appropriate standards of quality. Masonry prisms are tested in accordance with ASTM E 447 Test Methods for Compressive Strength of Masonry Prisms, Method B as modified by the MSJC Specifications. At least three prisms are required by the MSJC Specifications for each combination of materials. The average of the three tests must exceed f . Further explanation of prism testing procem dures is provided in Technical Notes 39B. Shear Strength The shear strength of a masonry assemblage may be separated into four parts: 1) the shear strength of the unit, mortar and grout assemblage, 2) the effect of the shear span-to-depth ratio, M/Vd, 3) the enhancement of shear strength due to compressive stress, and 4) the contribution of shear reinforcement in the masonry assemblage. All four phenomenon are represented in the allowable shear stresses provided in the MSJC Code. However, only the first and fourth items are controlled by material properties. Items two and three vary with member size and applied loads. The shear strength of the masonry assemblage is directly related to the properties of the unit, mortar and grout. Shear failure of a unit-mortar assemblage is by splitting of units, step-cracking in mortar joints, or a combination of the two. Unit splitting strength is increased by increasing the compressive strength of the unit. In general, unit splitting is not a common shear failure mode of brick or structural clay tile masonry. Unit splitting occurs in masonry assemblages of weak units and strong mortar and may also occur in shear walls which are heavily axially loaded. Cracking in mortar joints is the more common shear failure mode for brick and structural clay tile masonry assemblages. Mortar joint failure occurs by sliding along bed joints and separation of head joints. Mortar joint shear failure is affected by bond strength and the frictional characteristics between the mortar and the unit. In general, a unit-mortar combination which provides greater bond strength will also provide greater shear strength. Grouting the masonry assemblage will also increase shear strength by providing a shear key between courses. The shear strength of a masonry assemblage may be evaluated in accordance with ASTM E 519 Test 5

Method for Diagonal Tension (Shear) in Masonry Assemblages. The contribution of unit, mortar and grout to the allowable shear stresses stated in the MSJC Code are based on ASTM E 519 tests of masonry assemblages. Steel reinforcement may be added to the masonry assemblage to increase shear strength. Shear reinforcement should be provided parallel to the direction of applied shear force. The MSJC Code also requires a minimum amount of reinforcement perpendicular to the shear reinforcement of one-third the area of shear reinforcement. When shear reinforcement is provided in accordance with the MSJC Code, allowable shear stresses given in the MSJC Code for reinforced masonry are increased three times for flexural members and one and one-half times for shear walls. Flexural Tensile Strength Reinforced brick and structural clay tile masonry is considered cracked under service loads and the flexural tensile strength of the masonry is neglected in design. However, cracking of an unreinforced brick or structural clay tile masonry member constitutes failure and must be avoided. Thus, flexural tensile strength is an important design consideration for unreinforced masonry. Flexural tensile strength is the bond strength of masonry in flexure. It is a function of the type of unit, type of mortar, mortar materials, percentage of grouting of hollow units and the direction of loading. Workmanship is also very important for flexural tensile strength, as unfilled mortar joints or dislodged units have no mortar-to-unit bond strength. Allowable flexural tensile stresses stipulated in the MSJC Code for unreinforced masonry are given in Table 6. The allowable flexural tensile stresses for portland cement-lime mortars are based on full-size wall tests in accordance with ASTM E 72 Method of Conducting Strength Tests of Panels for Building Construction. Values for masonry cement and air-entrained portland cement-lime mortars are based on reductions obtained with comparative testing. Flexural tensile strength may be evaluated by testing small-scale prisms in accordance with ASTM E 518 Test Method for Flexural Bond Strength of Masonry or ASTM C 1072 Test Method for Measurement of Masonry Flexural Bond Strength, but these results may not directly correlate to the allowable flexural tensile stresses in the MSJC Code. Elastic Modulus The elastic modulus of the masonry assemblage, in combination with the moment of inertia of the section, determines the stiffness of a brick or structural clay tile masonry structural element. Elastic modulus is the ratio of applied load (stress) to corresponding deformation (strain). The elastic modulus is roughly proportional to the compressive strength of the masonry assemblage. Testing of brick masonry prisms indicates that the elastic modulus of brick masonry falls between

TABLE 6 MSJC Code Allowable Flexural Tensile Stress for Unreinforced Masonry, psi (MPa)Mortar Type Portland cement-lime Masonry cement and air-entrained portland cement-lime M or S N

Direction of Stress

Masonry Type Solid units

M or S

N

40 (0.28) 25 (0.17)1

30 (0.21) 19 (0.13) 58 (0.40) 60 (0.41) 38 (0.26) 60 (0.41)

24 (0.17) 15 (0.10) 41 (0.28) 48 (0.33) 30 (0.21) 48 (0.33)

15 (0.10) 9 (0.06) 26 (0.18) 30 (0.21) 19 (0.13) 30 (0.21)

Normal to bed joints

Hollow units ungrouted Hollow units fully grouted Solid units

68 (0.47) 80 (0.55) 50 (0.34) 80 (0.55)

Parallel to bed joints

Hollow units ungrouted and partially grouted Hollow units fully grouted

1For partially grouted masonry allowable stresses shall be determined on the basis of linear interpolation between hollow units which are fully grouted or ungrout-

ed and hollow units based on amount of grouting.

700 and 1200 times the masonry prism compressive strength [4]. If the Unit Strength Method is used to show compliance with the specified compressive strength of masonry, f , an accurate estimation of the m actual compressive strength of the masonry assemblage may not be known. Consequently, the elastic modulus of the masonry assemblage is determined by the mortar Type and the unit compressive strength. See Table 7. The data in Table 1 can be used to estimate the modulus of elasticity of the masonry assemblage for the type of unit selected. The elastic modulus of grout is computed as 500 times the compressive strength of the grout in accordance with the MSJC Code. In general, the elastic modulus of grout and the elastic moduli of brick or structural clay tile and mortar masonry assemblages are comparable and are often considered equal for design calculations. However, the MSJC Code recommends that the method of transformation of areas based on relative elastic moduli be used for computation of stresses in grouted masonry elements. Dimensional Stability Dimensional stability is also an important property of the masonry assemblage. Expansion and contraction of the brick or structural clay tile masonry may exert restraining stresses on the masonry and surrounding elements. Material properties which affect dimensional stability of clay and shale unit masonry are moisture expansion, creep and thermal movements. Effects of these phenomenon may be evaluated by the coefficients provided in the MSJC Code, which are listed in Table 8. The coefficients in Table 8 represent average quantities for moisture expansion and thermal move6

ments and an upper-bound value for creep. Moisture expansion and thermal expansion and contraction are independent and may be added directly. The magnitude of creep of clay or shale unit masonry will depend upon the amount of load applied to the masonry element.TABLE 7 Elastic Moduli of Clay and Shale Masonry Assemblages1Assemblage Elastic Modulus, psi (kPa) x 106 Type M mortar 3.0(20.7) 3.0(20.7) 2.8(19.3) 2.2(15.2) 1.6(11.0) 1.0 (6.9) Type S mortar 3.0(20.7) 2.9(20.0) 2.4 (16.5) 1.9(13.1) 1.4 (9.7) 0.9 (6.2) Type N mortar 2.8(19.3) 2.4(16.5) 2.0(13.8) 1.6(11.0) 1.2 (8.3) 0.8 (5.5)

Net Area Compressive Strength of Units, psi (MPa)

12000 (82.7) and > 10000 (68.9) 8000 (55.2) 6000 (41.4) 4000 (27.6) 2000 (13.8)1MSJC Code Table 5.5.1.2.

TABLE 8 MSJC Code Dimensional Stability Coefficients for Clay and Shale Unit MasonryMaterial Property Irreversible moisture expansion Creep Thermal expansion and contraction1

REFERENCES 1. Atkinson, R.H., Evaluation of Strength and Modulus Tables for Grouted and Ungrouted Hollow Unit Masonry, Atkinson-Noland and Associates, Inc., Boulder, CO, November 1990, 47 pp. 2. Building Code Requirements for Masonry Struc tures and Commentary (ACI 530/ASCE 5/TMS 402-92) and Specifications for Masonry Struc t u re s and C o m m e n t a ry (ACI 530.1/ASCE 6/TMS 602-92), American Concrete Institute, Detroit, MI, 1992. 3. Kingsley, G.R., et al., The Influence of Water Content and Unit Absorption Properties on Grout Compressive Strength and Bond Strength in Hollow Clay Unit Masonry, Proceedings 3rd North American Masonry Conference, The Masonry Society, Boulder, CO, June 1985, pp. 7:112. 4. P l u m m e r, H.C., Brick and Tile Engineering, Brick Institute of America, Reston, VA, 1977, 466 pp. 5. Steel Reinforcement Properties and Availability, Report of ACI Committee 439, Journal of the American Concrete Institute, Vol. 74, Detroit, MI, 1977, p. 481. 6. Subasic, C.A., Borchelt, J.G., Clay and Shale Brick Material Properties - A Statistical Report, submitted for inclusion, Proceedings 6th North American Masonry Conference, The Masonry Society, Boulder, CO, June 1993, 12 pp.

Coefficient 3x10-4 in./in. (3x10-4 mm/mm) 0.7x10-7 in./in./psi (1x10-5 mm/mm/MPa) 4x10 -6 in./in./oF (1x10 -5 mm/mm/oC) 1

Conversion based on equivalent deformation at 100oF (38 oC).

SUMMARY This Technical Notes contains information about the material properties of brick and structural clay tile masonry. This information may be used in conjunction with the MSJC Code and Specifications to design and analyze structural masonry elements. Typical material properties of clay and shale masonry units, mortar, grout, reinforcing steel and combinations of thes