module 2 cvl 301.05 (p).doc

PARTICIPANT MODULE CVL 301.05NSN

SAUDI ARAMCO

SAP BET ID 40009511

INSPECT CONCRETE POST-POUR

WARNING: The training materials contained in this manual are the property of the Saudi Arabian Oil Company (Saudi Aramco) and are intended for the exclusive use of Saudi Aramco employees enrolled in advanced inspection training workshops. Any material contained in this manual which is not already in the public domain, may not be copied, reproduced, sold, given or disclosed to third parties or otherwise used, in whole or in part, for purposes other than for use in Saudi Aramco’s Professional Engineering Development Unit courses without the prior written permission of the Chief Engineer of Saudi Aramco.

CVL 301.05 (SAP ID 40009511)PARTICIPANT REVISION

DATE REVISION DESCRIPTION PAGE(S) AFFECTED

03/02/02 RE-SCANNED FIGURES ALLCONVERTED MODULE FROM MAC-FORMAT TO PC-FORMAT ALLINCORPORATED MARK-UPS BY A. W. CORNISH,SR. CIVIL INSTRUCTOR, T&DG/AU/ID, AFTER 1ST REVIEW ALL

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CVL 301.05 (SAP ID 40009511)PARTICIPANT TABLE OF CONTENTS

MODULE COMPONENT PAGE

OBJECTIVES 1

Terminal Objective 1

Enabling Objectives 1

INTRODUCTION 2

Purpose 2

Scope 2

INSPECTING THE CONCRETE FINISHING 3

Finish Tolerances 4

Types of Surfaces 6

Tools Used for Leveling and Finishing 7

Leveling Concrete 8

Tools Used for Finishing Concrete 13

Techniques of Finishing Concrete 14

INSPECTING THE CONCRETE CURING 24

Description and Purpose of Curing 24

Effects of Weather on Curing 26

Curing Methods29

Curing Materials 30

Curing Specific Structures 34

Curing Exterior Walls, Columns and Bridge Piers 35

Curing Interior Concrete Surfaces 35

Inspection Points 36

PERFORMING TEST FOR HARDENED CONCRETE 37

Sampling Hardened Concrete 37

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DOCUMENTING INSPECTION RESULTS 41

Field Notes 41

Site Logbook 41

Projects Inspection Report (Saudi Aramco Form 8213-ENG) 42

Laboratory Testing Forms 44

EXERCISE 1. INSPECTING THE CONCRETEFINISHING 46

EXERCISE 2. INSPECTING THE CONCRETECURING 51

EXERCISE 3. PERFORM TESTS FOR HARDENEDCONCRETE 54

EXERCISE 4. DOCUMENT INSPECTIONRESULTS 57

Exercise 4A. Make Field Notes in Field Notebook 58

Exercise 4B. Complete the Proper Document of the Inspection Findings 58

Exercise 4C. Complete Saudi Aramco Form 8563 58

Exercise 4D. Complete a Laboratory Request Form 58

WORK AID 1. HOW TO INSPECT THECONCRETE FINISHING 59

WORK AID 2. HOW TO INSPECT THECONCRETE CURING 60

WORK AID 3. HOW TO PERFORM TEST ONHARDENED CONCRETE 61

Sampling Hardened Concrete 61

Onsite Tests for Hardened Concrete 62

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WORK AID 4. HOW TO DOCUMENT THEINSPECTION RESULTS 64

Work Aid 4A. Make Field Notes in a Field Logbook 65

Work Aid 4B. Make Entries in the Site Logbook 68

Work Aid 4C. How to Complete a Projects Inspection Report (PIR) 70

Glossary 73

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CVL 301.05 (SAP ID 40009511)PARTICIPANT OBJECTIVES

OBJECTIVES

Terminal Objective

Upon completion of this module, the participant will be able to inspect concrete postpour, in accordance with applicable standards.

Enabling Objectives

In order to accomplish the terminal objective, the participant will be able to accomplish the following:

◊ Inspect the concrete finishing,

◊ Inspect the concrete curing,

◊ Perform test on hardened concrete.

◊ Document the inspection results.

Note: This training material has been developed using the latest available versions of applicable Saudi Aramco and industry standards. However, these documents are regularly updated. Therefore, it is the responsibility of the inspector to ensure that he is conducting his inspections according to the latest versions of these documents.

Note: Italicized words are found in the glossary.

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CVL 301.05 (SAP ID 40009511)PARTICIPANT INFORMATION

INTRODUCTION

Purpose

The purpose of concrete post pour is to provide Saudi Aramco with the means of assuring quality construction. You must perform post pour inspections to verify that the vendor has met all Saudi Aramco requirements.

You are responsible for inspecting and verifying all details concerning concrete postpour procedures. You will learn how to inspect the finishing and the curling of concrete and the tests required for hardened concrete.

You will perform the inspections according to Saudi Aramco Engineering Standards, using methods determined by the American Concrete Institute (ACI), the American Society for Testing and Materials (ASTM) and the Uniform Building Code (UBC) Standards. After each inspection you will document your findings using specific Saudi Aramco forms.

You must know all Saudi Aramco requirements and procedures for inspecting concrete post pour. You will conduct all test procedures exactly as stated In the Saudi Aramco Engineering Standards and other industry standards for hardened concrete.

It is the purpose of this module to give you the knowledge and skills to do all these things.

Scope

This module does not cover the actual placement of the concrete. It starts at the finishing process after the concrete has been poured. It does not cover the installation of the formwork or any placement of embedded objects, other than those used to perform in-place strength test on the concrete once it is hardened. Those subjects are covered in module CVL-301.03, Inspect Concrete Prepour. This module does not cover testing of the plastic concrete. That subject is covered in module CVL-200.02. The testing covered in this module only pertains to hardened concrete.

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INSPECTING THE CONCRETE FINISHING

Finishing is the work performed after the concrete is placed and before it hardens. This work gives the concrete its texture and appearance. Finishing serves two purposes; it enhances the appearance and provides the required type of surface specified in the plans. You determine the quality of the concrete surface by examining the condition and the appearance of the finished product.

Finishing begins immediately after the workers place the concrete. It is usually required on all concrete surfaces that are visible. Examples of concrete surfaces that require finishing include sidewalks, floors and finished walls (interior and exterior). The specific type of finish is a result of how the workers place the forms and what methods the workers use to finish the surface. You must verify that the workmen finish the concrete surface to tolerances and textures according to Saudi Aramco standards and the American Concrete Institute specifications.

The construction plans and Scope of Work will usually specify the procedures and materials needed to achieve the desired finish. Following are some of the specifications usually found for finishing in the plans:

◊ The plans will require only a uniform, rough finish when the building specifications require subsequent toppings of concrete, mortar, asphalt, flooring roofing or other similar building materials.

◊ For inset tile and linoleum, the plans usually require relatively level and smooth finishes and the workers must repair any cracks.

◊ For sidewalks and other outdoor concrete surfaces used by pedestrians, the plans, for safety reasons, usually requires a smooth or non-skid finish.

The main consideration is to use the minimum amount of surface manipulation to get the desired finish.

Following are the things you must know about inspecting concrete finishes:

◊ Finish tolerances

◊ Types of surfaces

◊ Tools used for finishing

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◊ Inspection points

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INSPECTING THE CONCRETE FINISHING (CONT'D)

Finish Tolerances

Tolerance is a term specifying the degree or depth of the finish. The two factors you use to calculate tolerance:

1. Flatness, which is a statistical analysis of elevation differences you determine by measuring a straight line at 12 inches (304.8 mm) intervals.

2. Levelness is a factor you determine by taking consecutive measurements of elevation differences at 10 feet (3.048 m) intervals along a straight line.

If using hand measurement procedures, concrete floors and slabs must finish to a levelness tolerance of 3/16 inch for every 10 feet (4.76 mm for every 3.048 m).

You may use a profilometer to verify that the finish meets the specifications and tolerances as noted on the design drawing and as specified in ACI 117, Standard Specifications for Tolerances for Concrete Construction and Materials and the ACI 301, Specifications for Structural Concrete (Use ASTM E 1155 for procedures for measuring and calculating the factors).

When placed upon the surface in the required manner, the profilometer will give an index number. A spring-loaded plunger with a fine tip on it accomplishes this. The tip measures the differences and displays them on a scale. Figure 1 is a table showing the American Concrete Institute (ACI) tolerances for floor finishes, according to levelness and flatness factors. These numbers are the minimum requirements. Slabs and floors that have levelness and flatness that do not meet these requirements are unsatisfactory.

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Finish Tolerances (Cont'd)

Figure 1. Table of recommended floor finish tolerances as specified in ACI 117

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Types of Surfaces

You classify concrete finished surfaces as either unformed or formed. Unformed finish requires only a small amount of finish to make them acceptable. Unformed finish is usually specified in areas where appearance is not important.

Formed finishes describe the degree of labor required for final finishing. Formed surfaces require more labor and effort than unformed. Formed finishing usually adds appearance or serviceability to the concrete.

Following are types of formed finishes:

Matching-sample finish

As-cast finish

Rubbed finished

Matching-sample Finish

Matching-sample finish requires that the contractor produce a sample showing the actual finished surface. The sample must measure at least 100 ft2 (9.29 m2) a designated location. You must verify that the sample matches the specifications before the workers can proceed with that specified finish for that area. Different areas or different finish requirements require another sample.

As-cast Finish

The as-cast finish has two sub-types:

1. Rough-form finish which requires tie holes and defects to be

patched, fins exceeding 1/4 inch (6.35 mm) in height must be chipped or rubbed off and to preserve the texture left by the forms.

2. Smooth-form finish requires the workers to fill all tie holes, patch any defects, remove of any fins, and give the surface a final rubbed finish.

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Types of Surfaces (Cont'd)

Rubbed Finished

Following are the types of rubbed finishes:

◊ The smooth-rubbed finish, requires the workers to remove the forms as early as can be permitted, followed by immediate patching of holes and defects. The concrete surface is then rubbed with a carborundum brick or other abrasive, after wetting until a uniform color and texture is achieved. The grout used in this process is the grout produced by the rubbing.

◊ Grout-cleaned finish requires that the workers first clean and prepare the surface. Next, the workers apply a coating of grout, consisting of 1- part Portland cement and 1 ½-parts of fine sand. The workers scrub the grout into all the voids and all the excess grout is then removed. When the grout starts to turn white, the workers rub the surface. The surface is kept damp for 72 hours. The grout mixture may require an addition of white cement to make the colors uniform.

◊ Cork-floated finish requires the forms to be removed as soon as possible, followed by any necessary patching. Finish is then done with a cork-covered float

Tools Used for Leveling and Finishing

There are numerous tools the workers use to level and finish concrete. Each tool serves a particular purpose. When you inspect finish work, you must know these tools and their specific purpose.

Following are the most commonly used tools for leveling work:

◊ Screed, leveling (see Figure 2)

◊ Mechanical screed (Mechanical vibrating strike-off machine) (not shown)

◊ Hand screed (see Figure 3)

◊ Bull float (see Figure 4)

◊ Hand-float (Darby)

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Leveling Concrete

Leveling is the work required to level the concrete after it is placed and vibrated to consolidate it. This work levels the concrete and ensures that the large aggregate are compacted into the mixture. When the concrete is placed, the workers immediately go to work leveling the concrete. During this time, you must ensure that the ambient conditions and the temperature are properly maintained.

Following are the methods that can be used to prefinish or level the concrete:

◊ Screeding (striking off)

◊ Tamping

◊ Bull floating

To prefinish (rough finish) and to level horizontal concrete surfaces, workers use a leveling screed. Figure 2 shows two workmen using a leveling screed. A leveling screed is a very long, straight length of 2” x 4” (50 mm x 100 mm) aluminum box section (or other similar material), used as a straight edge. The workers slide the straight edge back and forth in a sawing motion over the surface of the forms containing the fresh concrete. This motion flattens the cement and brings natural mortar and water to the surface which assists in the finishing and curing process. The screed is moved in one direction in this sawing motion until the workmen reach the end of the forms or until the poured section is done. The workmen always try to keep some cement mix in front of the screed to fill in the low spots. As the work progresses, the workers will use a shovel to add cement to low spots or remove it from high spots.

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Leveling Concrete (Cont'd)

Figure 2. Workers using a leveling screed to rough finish concrete

Sometimes a vibrator is mounted on the straight edge, which helps to consolidate it and level it. If the slab is to have a crown, the straight edge will have a curve in the middle section on the bottom side. Sometimes the slab will require drainage to only one side, such as to the lawn side of a patio next to a building. It would not be desirable to have the water drain toward the building. In this case, a long 2 x 4 piece of material may be placed upon the side opposite the direction of the required drainage. This will smooth the concrete and give a slight incline to the outside edge toward the lawn.

The screeding should be finished as soon as possible but before the bleed water appears on the surface. When the workers finish this phase, the concrete is approximately level, but it Is not smooth or finished.

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Hand Screed

After the workmen have rough-leveled the concrete, they use the blade of the hand screed to lightly tap on the surface of the concrete. This gently compresses and pushes the coarse aggregate below the surface and forces the fine aggregate, the water and the cement to the surface. This process levels the concrete and smoothes the surface. Figure 3 shows a worker using a hand screed.

Figure 3. A worker using a hand screed

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Bull Float and Darby

The workman uses the bull float or the Darby after he uses the hand or mechanical screed. These are used to further smooth out the rough surface of the concrete. The Darby is a handheld float with a shorter handle than the bull float. The Darby is sometimes used when the workers can walk on the concrete. The Darby produces a surface that is closer to the tolerances than the bull float. If the workers can not walk on the mixture, the bull float with a long handle is used as shown in Figure 4. The long handle allows the workman to level large areas of the concrete uniformly without having to step on the surface. The bull float made of aluminum is the last of the tools used by the workmen before setting begins.

There is a mandatory waiting period between the time the floating is done and the final finish work starts. This waiting period is absolutely necessary to permit the bleed water to leave the surface of the concrete.

Caution: It is a basic rule in finishing concrete that you never use any finishing tool on the fresh concrete while the bleed water is present on the surface.

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Bull Float and Darby (Cont'd)

Figure 4. A worker using a bull float

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Tools Used for Finishing Concrete

Following are the most common tools used in finishing the concrete (see Figure 5):

◊ Corner trowel (edger)

◊ Grooving trowel or groover

◊ Hand trowel (steel trowel)

◊ Finishing broom

◊ Mechanical trowel

Figure 5. Hand tool and equipment used for finishing concrete

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Techniques of Finishing Concrete

The five basic stages for concrete slab finish work are:

1. Edging

2. Grooving

3. Floating

4. Troweling

5. Brooming

All of these techniques may be used on a project, but sometimes they are not required. All five will usually be used of flat exterior surfaces where heavy foot traffic is expected, such as, sidewalks, outdoor patios, and pavilions.

Edging

In some construction, the edging is started right after the waiting period. In others, it is done after the float. At some point there will be a mandatory waiting period until the free water is gone.

Not all slabs require edging. If edging is required, it is the first finishing technique applied in the series of final finish operations.

The corner trowel (edger) is a fine detail trowel used in finishing. Figure 6 shows the use of this tool. The workman uses the corner trowel or edging trowel to place a uniform, rounded edge on concrete floors and slabs. This gives the edges of the concrete more strength and reduces chipping of this area. The workman places the corner trowel between the supporting form and the fresh concrete slab to square the edges or corners of the concrete surface. The corner or edging trowel is used after the bull float and normally, after the mandatory waiting period.

It may be necessary to add small amounts of concrete or mortar to small areas that are jagged from large aggregate holes. Do not allow the workmen to work the edges so much that they leave a deep impression on the top surface of the slab. These impressions are extremely hard to remove once they are made. Do not allow the workmen to add dry cement mix to the surface to soak up bleed water.

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Techniques of Finishing Concrete (Cont'd)

Edging (Cont'd)

Figure 6. Use of a corner trowel (edger)

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Grooving

The grooving trowel is used to make finished grooves in the concrete, such as the joints in concrete sidewalks and patio slabs. This can be done at the same time as the edging or it can be done after the edging is completed. The grooving trowel gives a stronger finished joint in the groove. These grooves relieve the pressure on the slab. If the cement cracks, it will usually crack along these grooves, which does not greatly affect the strength or appearance of the work The groover trowel is like a steel hand trowel with a grooved blade on the bottom called a bit The normal bit size for most slab construction is 3/4” (19.05 mm) or 1” (25.4 mm) deep. Figure 7 shows a groover being used on a concrete slab.

Figure 7. Use a grooving trowel to make grooves in slabs and sidewalks

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Floating

After edging and grooving, the workman uses the hand float to begin the third stage of smoothing the surface of the concrete. This floating procedure is done after the concrete initially sets. This is not to be confused with using a bull float to level the concrete. Bull floating is done while the cement is still fluid. Figure 8 shows the use of a hand float.

The purpose of floating the concrete is to smooth out rough spots left by the leveling process and to embed large aggregate underneath the surface of the concrete. This procedure slightly consolidates and tightens the surface. When properly done, the floating leaves the surface dense and smooth and ready for the steel troweling.

Hand floats are used for the floating procedure. They come in a variety of sizes and shapes and are made from different materials. The all-wood hand float is the most used one. Special floats are also available for special surfaces. These surfaces will depend on the final covering of the slab or floor. If the concrete is to be white concrete, be sure the workmen use plastic or stainless steel to prevent stains on the finished surface.

The time to start the floating depends on many factors, such as, temperature, wind, humidity, slump of the concrete and the type of subgrade. The time may be two hours after leveling is completed or it may be as long as eight hours. The factors you must depend on when determining when to start the floating are:

◊ The water sheen or shine must have disappeared from the concrete surface.

◊ The mix must be stiff enough that when you stand on the concrete surface, you will leave only a slight footprint, not more than 1/4” (6.35 mm) deep.

The footprints will be smoothed away during the floating procedure.

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Floating (Cont'd)

Figure 8. A worker using a hand float

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Troweling

The hand trowel or steel trowel is used in the final stages of the finishing. This produces a hard and dense surface. Figure 9 shows the use of this tool.

The hand trowel is usually made of metal and is sometimes called a steel trowel, although they can be made of other materials. There are special trowels for special purposes. Some have special rounded ends for work on rounded surfaces.

The workman uses the hand trowel over small areas of concrete during the final stage of surface finishing. He uses the trowel before the final set of the concrete. The hand trowel gives the concrete surface a very smooth finish. This finish is called a hand-troweled finish.

The first troweling is done as soon as the surface is floated. The blade is kept as flat against the surface as possible. If the blade is not held flat against the surface, it will vibrate (chatter) and produce a rough, wavy effect in the surface. Ensure that the troweled surface is smooth and free of defects. Additional troweling can improve the smoothing. Each additional troweling is done after a short time lapse to increase the set of the concrete. A smaller trowel is necessary on each additional troweling so the worker can apply greater pressure on the concrete surface.

The successive troweling are done with the blade at a slight angle to the surface. This allows the back side of the blade to exert pressure and smooth the surface.

The final troweling (burnishing) is called a hard trowel and is also done with the blade at the proper angle. You will know this is done correctly by the ringing sound the trowel makes as it passes over the surface.

The use of power tools sometimes replaces the troweling procedure. This is discussed later.

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Troweling (Cont'd)

Figure 9. A workman using a hand trowel

Sometimes bubbles and blisters will appear in the concrete surface during troweling. This may happen when the partially hardened slab is sprayed with water and then sprinkled with dry cement. This is caused by the water getting trapped in the aggregate voids under the cement topping. This procedure of cement topping should never be allowed.

Any of the finishing operations done while water is still on the surface may cause scaling. Excessive early troweling may result in crazing.

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Brooming

The concrete surface from troweling is hard, dense and very smooth, but it is also slippery, especially when it becomes wet after curing. To provide a nonslip finish, the workman uses the finishing broom. Any degree of roughness can be obtained, depending on the type of brush or broom used and the time at which the brushing is done.

Figure 10 shows a workman pulling the broom over the surface of the concrete. The broom bristles comb the concrete surface and leave an abrasive finish. You call this abrasive finish a broom finish.

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Figure 10. A workman using a finishing broom

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Mechanical Finisher

Most concrete slabs and floors require a broom finish or a hand-troweled finish. Sometimes the construction plans specify a mechanical finish. The workman uses a mechanical finisher to provide a smooth, uniform finish. The mechanical finisher, also called a power float, has an engine that rotates four blades. Some mechanical finishers have three rotary engines. The rotating blades smooth the concrete surface until the required finish is obtained. Figure 11 shows a single rotary mechanical finisher.

Bubbles may appear from starting power troweling too early or by troweling with the front of the trowel angled too high. This causes troweling with only the back side of the blade. This causes the surface to seal too early and traps air under the surface. This can be avoided by troweling when the right time is indicated and by operating the power trowel with the blades at the proper, flat angle.

Figure 11. A workman using a mechanical finisher

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Verification

During concrete finishing, you must verify that the workmen follow following procedures:

◊ Every precaution is taken to prevent finishing faults. You must verify that the concrete is properly leveled and ready to finish.

◊ The timing and the removal of forms, after initial setting is correct. Do not allow temporary forms and props to be removed to quickly.

◊ No finishing operation is performed while free water is still present on the surface.

◊ The amount of finishing necessary is kept to a minimum to produce the required surface.

◊ Do not overwork the fresh concrete during finishing or begin troweling too soon after placement. Troweling should begin after all free water is gone and after the initial rest period.

◊ The finish meets the specifications and tolerances according to Saudi Aramco and industry specifications.

Refer to Work Aid 1 for steps on how to verify concrete finishing.

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INSPECTING THE CONCRETE CURING

Description and Purpose of Curing

Curing is the process involving monitoring fresh concrete to assure sufficient levels of water during hydration. Curing promotes hydration, which is the chemical process of the reaction of cement and water. This process starts when the two products are placed together and continues in a steadily decreasing rate for month or even years. If there is not enough water, hydration of the cement will stop and there will be no further gain in strength and durability of the concrete. There is a sufficient amount of water in the right mixture of concrete for the hydration. It is your job to ensure that it is retained during the curing process. This is done by not allowing the water in the concrete to evaporate, but to be consumed by the hydration process. You ensure retention by one of the following curing methods:

◊ The application of water directly or through some material in contact with the surface that holds a reservoir of water.

◊ The use of a seal material, such as polyethylene or curing compound, to prevent or retard the escape of moisture from the concrete.

Alternate wetting and drying will do more damage than no curing at all.

Curing makes good, durable concrete. If concrete is not properly cured it has low strength, poor durability and other deficiencies that affect the usefulness and beauty of the cement structure.

Your job during the curing process is to ensure that sufficient water is provided. In some manner so as to continue this process for at least 7 days, as specified in SAES-Q-001, Paragraph 10.3, which states, “Water curing shall be continuous until the compressive strength has reached 70% of the specified strength, but not less than 7 days after placement.” Concrete increases in strength almost indefinitely if it is kept moist, but dry concrete quickly reaches its curing limit as shown in Figure 12. Notice that after about six months, the curing of the dry concrete stops and at one year the dry concrete is only about half as strong as it would have been if wet.

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INSPECTING THE CONCRETE CURING (CONT'D)

Description and Purpose of Curing (Cont'd)

Figure 12. Graph comparison of curing wet and dry concrete

You must verify that all types of concrete are cured in the specified way. Improper or non-uniform curing procedures will cause following defects:

◊ The formation of voids and honeycombing resulting in the lowering of strength of concrete.

◊ A variation in the color of the surface of the concrete.

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Effects of Weather on Curing

All the various aspects of weather have an effect of the curing process. But, most important are heat, cold and vapor. Figure 13 shows the effects of heat and cold.

Hot Weather

High temperatures during hot weather adversely affect the curing of

concrete. A concrete temperature of 80ºF (26.6ºC) or above during and immediately after placing will result in lower strength compared with

concrete mixed and placed at 40ºF to 80ºF (4.44ºC to 26.6ºC). Figure 13A shows how high temperature affects the strength of concrete. Notice that concrete made and cured at a high temperature has high early strength up to four or five days, but beyond that time, the strength is not as good as concrete made and cured at a temperature

of 73ºF (22.7ºC).

More moisture is required as the temperature rises. At 70ºF (21.1ºC), 0.016 lbs of water are required per pound of air to maintain a 100%

humidity rate. For the same situation, with a temperature of 140 ºF

(60ºC) it requires 0.15 lbs of water and at 180ºF (82.2ºC), it requires 0.66 lb of water.

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Effects of Weather on Curing (Cont'd)

Cold Weather

Figure 13B shows that concrete made and cured at low temperatures

does not develop strength like concrete cured at 73ºF (22.7ºC). Cold weather requires heating to keep the concrete warm. Heating the concrete makes it difficult to maintain sufficient moisture. It is usually recommended not to remove the forms in cold weather during curing. Curing compounds are used because water for curing cannot be used in cold weather. Observe following precautions for curing concrete in cold weather:

◊ Provide insulation and heated enclosures, as necessary.

◊ Heat enclosure with steam and blowers instead of stoves.

◊ If heaters are used, vent them outside the enclosure and raise them above surface level.

◊ Leave forms in place as long as possible.

◊ Maintain the proper temperature as specified.

◊ Avoid overheating the concrete.

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Effects of Weather on Curing (Cont'd)

Cold Weather (Cont'd)

Figure 13. Effects of temperature on curing of concrete

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Curing Methods

Curing methods can be grouped into two general categories:

1. those that supply additional moisture to the concrete, and,

2. those that prevent loss of moisture from the surface by sealing

Curing of the concrete is probably the most violated portion of the concrete construction process. Any common method of curing will give the type of concrete required, if the method is properly applied.

Supplying Additional Moisture

In this category of curing are such methods as sprinkling, ponding and wet covers of various kinds. The problem arises in the difficulty of keeping the concrete continuously wet. Frequently, workers sprinkle water one time a day and go on to their other jobs. This once a day sprinkling will not provide the amount of water required. In situations such as this, the water curing does not work as well as it should. In fact, sometimes intermittent watering is worse than no watering at all, depending on the temperature. Water sprinklers, soaker hoses and other means of keeping the entire surface wet are the best methods. Pieces of burlap loosely draped over the concrete, whether wet or dry, do little for the curing process. Alternating wet and dry are worse than no wetting at all.

Another way to supply additional moisture is to use a moistened material such as burlap blankets and mats of cotton or other material. Even these however should be kept constantly moist by a sprinkling method.

Preventing Loss of Moisture

This method can be classified as sealing, either with a plastic material or a compound. The function of this method is to seal the water that is already in the concrete so it will not escape, thus making it available for curing. This method does not supply any additional water, but it does supply moisture that would have been lost without the seal.

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Curing Materials

Following are the materials that are use for curing:

◊ Water

◊ Wet coverings

◊ Immersible sheet material

◊ Sealing compounds

Water

The water used for curing concrete must be sweet water (1000 ppm TDS). Concrete mixing water is also suitable for curing water. An adequate sweet water supply must be available to the workers at all times during the curing process. If you have any doubts about the supply of water for curing, send a sample to the laboratory for testing. Refer to the section on documenting the inspection results and Work Aid 4 for information about completing this form and the results you will obtain from the laboratory.

Wet Coverings

Burlap, cotton mats and other moisture retaining fabrics are commonly used in curing, particularly on surfaces that are not flat and which are difficult to keep wet. Burlap sacks used for storage containers must be thoroughly cleaned of all material so that it will not cause harm to the fresh concrete. Some burlap is resistant to rot and fire. New burlap should be washed to remove the material which they are treated with called sizing. Washing will remove the sizing which is a waterproof coating and will make the burlap more absorbent. Curing mats may be made from cotton or similar materials. The outside cover is usually waterproof to aid in retaining the moisture. Therefore, these mats must be watered and then placed upon the structure. Watering the outside cover will do no good. Sometimes a small water tube is placed inside these covers to provide a steady flow of water. The mats are usually quilted to absorb more water. They become quite heavy when saturated so they must be properly secured so that they will not slip off the surface.

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Curing Materials (Cont'd)

Impermeable Sheet Material

Slabs and pavements are frequently cured by covering with an impermeable sheeting of some type. ASTM C 171 specifies three types of material:

◊ Waterproof paper, either regular or white. Ensure that it is in two layers with padding between. Ensure that it is factory treated to provide high wet strength.

◊ Polyethylene film, clear or white, of at least 6 mils (0.15 mm) thickness. The clear film should be transparent and the white film should be opaque.

◊ White burlap-polyethylene sheet

Check the material to ensure that it is strong tough and resilient. It must be strong and thick enough to withstand the heat and the wind that is present during summer in Saudi Arabia. It should withstand normal use without puncture or tearing. Any holes will allow the water to evaporate and not be usable during the curing process.

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Sealing Compounds

Sealing compounds are used to seal the surface of new concrete after it has been finished. It prevents the loss of moisture from the concrete, thereby retaining it for the hydration process. This material is known by various names such as sealing compound, curing compound and membrane-forming compound. It is a paint-like liquid that, when sprayed on concrete, forms a watertight membrane on the surface. This holds the free water in the concrete mixture while it cures. ASTM C 309 gives the specifications for these types of compounds:

◊ Type 1 - Clear or translucent without dye

◊ Type 1-D - Clear or translucent with fugitive dye

◊ Type 2 - White pigmented

These compounds are placed in a liquid for delivery through the spray. This liquid is called the vehicle. Following are the restrictions on the types of vehicles that can be used with the various types:

◊ If the compound is classified as Type A, there are no restrictions on the vehicle.

◊ If the compound is classified as Type B, all vehicle solids are limited to all resin material.

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Sealing Compounds (Cont'd)

Ensure these things about the compounds:

◊ If dye is used, it is distinctly visible for at least four hours and fades completely in not more than one week

◊ It is a consistency suitable for spraying

◊ It is nontoxic

◊ It adhere to vertical and horizontal surfaces when properly applied

◊ Clear compounds should not darken the natural color of the concrete

◊ The workmen do not apply the curing compound until the concrete has initially hardened

The ready-mixed compounds must be vigorously stirred after receipt and before spraying. Although they are ready-mixed, the compound and the vehicle will separate when stored. Usually the drums in which the compound is shipped have agitators. To ensure proper mixing be sure the agitator is operated before and during spraying.

Water-emulsion, resin-based compounds are being widely used now in areas where solvent-release materials are prohibited. These water-emulsion, resin-based compounds satisfy the requirements of ASTM Type 1, Class B and ASTM Type 2, Class B.

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Curing Specific Structures

Different concrete structures are cured in different manners mainly because of their shape and intended purpose.

Curing Exterior Flat Concrete Surfaces

To monitor the curing of large flat areas, such as pavements, roofs, bridge decks and exterior floors, you must verify that the workers maintain the best temperature and moisture levels. The first step is to prevent rapid drying of the concrete surface. The workers must use a lightweight film, such as polyethylene film, to protect the concrete. This will produce a fine fog that will retain the moisture. The workers must properly seal the polyethylene film along the edges to prevent the wind from blowing under the plastic cover. This method usually doesn’t require much labor or an extensive water supply.

Flat slabs can be cured simply and properly by building a small earth dike around them and flooding it with water. This method called ponding is especially suitable for small slabs on grade. If ponding is to be use on suspended slabs, the shoring and formwork will require construction to withstand this extra load. On footings and below grade walls, a moist-earth backfill can be used for curing as soon as the concrete has hardened to withstand the earth pressure. Additional props may be required in this case, which should be engineered into the plans. The disadvantages of using earth backfill are that it may contain chemicals harmful to the concrete and it may stain the concrete. Therefore, this method should only be used in areas where appearance is not a primary consideration. As soon as the backfill is removed, the walls and footings should be cleaned with a cleaner that meets Saudi Aramco specifications for concrete cleaning.

On uniform surfaces such as the tops of walls or girders, wet burlap mats should be used as soon as the concrete has hardened sufficiently. This is particularly important at construction joints, which cannot be cured with sealing compound.

The workers may also use sand, provided they use a steady stream of water to keep the surface wet. This method is not always feasible or possible here in Saudi Arabia, because the sand has so much of the compounds chloride and sulfate. These compounds are detrimental to

36


new concrete. Clean sand is expensive to make in country or ship from abroad.

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Curing Exterior Walls, Columns and Bridge Piers

The procedure for curing vertical exterior surfaces is similar to curing horizontal surfaces with one exception. After removal of the forms, the workers will use a liquid membrane-forming compound sprayed, rolled or brushed on the fresh concrete. This sprayed-on compound will retain the necessary moisture in the same way a layer of polyethylene placed over a horizontal concrete surface.

A method for curing pier abutments is to have workers place sheets of polyethylene or burlap over and around the vertical surfaces and apply a steady trickle of water between the concrete and the airtight polyethylene cover. The sprayed water will cure the concrete satisfactorily but will not give much protection against the solar heat. This is only practical where there is an abundance of fresh mineral-free water. The water must not contain any sulfides or iron. These minerals will permanently stain the concrete.

Curing Interior Concrete Surfaces

Workers can proceed with curing inside enclosed buildings using any of the following: methods:

◊ Liquid membrane-forming compound

◊ Impervious sheet material, such as paper or plastic

◊ A fine spray from a hose, if the room is closed to maintain high humidity

◊ Use of absorbent covers, such as burlap, cotton mats, washed sand or sawdust

If workmen will be moving about on the concrete during the curing periods, use wet washed sand or sawdust instead of the membrane curing method to protect the concrete from abrasion. However, the workers must keep the sand or sawdust wet and keep it deep enough to protect the surface until the curing is complete.

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Inspection Points

During concrete curing, you must verify that the workmen follow following procedures:

◊ Maintain the optimum temperature range for the concrete immediately after placing.

◊ Maintain a stream of water over the mixture at all times. The supply of water for hydration is always of primary importance. Alternate wetting and drying will do more damage than non-curing at all.

◊ Do not apply any curing compound until the concrete has initially hardened.

◊ Tightly secure the polyethylene to prevent the wind from blowing under the plastic cover.

◊ If workmen will be moving about on the concrete during the curing periods, you must verify they use wet sand or sawdust instead of the membrane curing method to protect the concrete from abrasion.

Refer to Work Aid for procedures on inspecting concrete curing.

39


PERFORMING TEST FOR HARDENED CONCRETE

There are several ASTM standards for sampling hardened concrete and testing concrete for strength, percent of air, specific gravity and cement content. These tests are usually performed by the laboratory on hardened concrete and are only performed in case there are questions or resulting problems. You may be required to collect and prepare the samples for these tests, so the emphasis will be on sampling for these tests and on-site hardness testing

Sampling Hardened Concrete

Core Sampling

One of the most common way of sampling hardened concrete is to extract core samples from the structure using a diamond drill. The diameter of the core depends on the following:

◊ The thickness of the concrete member being sampled

◊ Maximum size of the aggregate (MSA) in the concrete. The diameter of the core must be at least twice the size of the nominal MSA; three times the size is even better

◊ The presence of embedded Items that might be damaged by drilling

Check the drill to ensure that it Is In good operating condition and that it is well anchored. Any looseness in the machine or loose bearings may cause the bit to wobble which may damage the core.

ASTM C 42 covers the removal of cores and sawed beams from hardened concrete. Samples should be representative of the concrete placed. Avoid any obvious defects or discontinuities. If you can identify the area by the batch number, you should take the core near the center of the area where the batch was placed. The ratio of the length to the diameter of the core should be about 2:1, however shorter ones may be required to avoid damage to embedded items. Any core with a length of less than 95% of its diameter should not be used for compressive strength testing.

Cores may be taken for purposes other than strength test Core samples are used to check the depths of honeycomb, surface deterioration, thickness of slab or to examine construction joints.

40


Honeycombs occur where the areas around the aggregate do not fill with cement during the pour. This is usually a result of poor consolidation techniques. The result is a rough surface with cavities up to several inches deep. Honeycombs may extend completely through the member and make it structurally unsound. This condition is more common in vertical surfaces than in horizontal surfaces.

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PERFORMING TEST FOR HARDENED CONCRETE (CONT'D)

Sampling Hardened Concrete (Cont'd)

Core Sampling (Cont'd)

The location of the cores for these purposes will depend on the surface appearance of the concrete and the best approach to the affected area.

Most coring and cutting machines use water for lubricating and cooling. Samples taken in these ways will not be sufficient for moisture tests.

Broken Concrete Samples

Samples of concrete broken from the structure are sometimes sent to the laboratory for analysis or testing. The sample should be taken so that it is representative of the portion of the concrete requiring testing. Select several pieces, if possible or a single piece, if necessary. The total should be about 300 mm of samples for concrete with 20 mm (or more) MSA.

Mark each sampling with sufficient information to identify the location from which it was taken. Include the batch number for that area, if available. Place each sampling (area) in a different sample bag or box, Samples should be well padded and protected from breakage. If moisture content is important, place the sample in a moisture proof plastic bag.

Regardless of any other tests, there should be tests for specific gravity and density of the concrete. Some of the sample for these tests must be boiled prior to testing. These boiled samples must not be use for strength testing.

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Onsite Tests for Hardened Concrete

Testing of hardened concrete on-site usually consists of two categories of tests; in-place strength testing and nondestructive strength testing

In-place Strength Testing

This test is usually accomplished by a device inserted into the concrete in some manner and then removed. The amount of energy required to remove the device is recorded. This data is used to determine the in-place strength of the hardened concrete.

Following are the two methods of doing this test:

1. An insert is embedded into the fresh concrete when it is poured. Once the concrete has hardened, this insert is pulled out of the hardened concrete and the results are determined and recorded. This method is covered in ASTM C 900

2. In this method, a hole is drilled into the hardened concrete and a special device is inserted into the hole. This insert is then removed and the results determined and recorded.

In both methods, the force required to pull out the inserted device is a measure of the strength of the hardened concrete.

Nondestructive Strength Testing

Impact devices are used to determine the strength of hardened concrete. There are two instruments used for this purpose; the Swiss hammer (also called the Schmidt hammer), used for what is commonly called hammer testing and the Windsor probe used for testing at greater depths of the concrete. The Swiss hammer uses a spring actuated plunger that strikes the concrete and measures the rebound of the tip (hammer). This tool is commonly called the rebound hammer. For Information on the rebound hammer, refer to module, CVL 200.02, Concrete Testing.

The Windsor probe is similar to the Swiss hammer in both use and results. The main difference is that this tool is activated by a cartridge filled with gun powder, similar to the cartridge-driven fastening tools, such as the Ramset fastening tool. The powder-filled cartridge

43


explodes actuating a probe that strikes the concrete surface. The rebounding force is an indication of the strength of the hardened concrete.

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Onsite Tests for Hardened Concrete (Cont'd)

Nondestructive Strength Testing (Cont’d)

Warning: If the Windsor probe is used, ensure that it is used safely in accordance with the manufacturer’s instructions. It uses a powder-filled cartridge (like a blank cartridge used in a gun). It is very powerful and can be deadly at close range. Do not point it at yourself or anyone else while it is in use.

45


DOCUMENTING INSPECTION RESULTS

The Inspection results will be documented on the project Inspection forms as specified in Saudi Aramco Engineering Procedure, SAEP-1150.

Field Notes

Write you findings in your field notes to record data and Information about your inspection. These notes are personal observations about an inspection. Record all of your observations, findings, conclusions and recommendations about the inspection. You will use these notes later when you make logbook entries, complete the required forms or write your reports.

Site Logbook

Use the inspection Logbook maintained on site to communicate with the construction agency. Logbook entries are the most common form of communication with the agency. SAEP-1150, Paragraph 9.4, explains the inspection logbook. Figure 14 illustrates a completed page from a logbook. The pages in the logbook are numbered for reference purposes.

Use the site logbook to record any initial findings during the preparation for the inspection and any findings in the finishing, curing and testing procedures. The discrepancies in the finishing inspection may require corrective action before the curing can begin. Refer to module on “Write Inspection Reports (Generic)," for more information and work aids on how to complete these forms. When a discrepancy/ies is satisfactorily completed, you must always legibly sign the logbook entry in the far right-hand column across from the original entry. Notice, in the figure, that one item has been completed and signed off. The other item has still not been accomplished or cleared.

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DOCUMENTING INSPECTION RESULTS (CONT'D)

Site Logbook (Cont'd)

Figure 14. Example of inspection logbook

Projects Inspection Report (Saudi Aramco Form 8213-ENG)

By the time you get to the point of testing the hardened concrete, the site logbook may not be available. Also, on small jobs, there may not be a site logbook. In either case, use the Projects Inspection Report to call attention to a problem. Saudi Aramco Inspection Procedure, SAEP-1150, explains the Projects Inspection Report. Supporting documentation for the report, such as, sketches, are also made a part of the report Figure 15 shows a completed Projects Inspection Report.

Note: Refer to SAEP-1150 for other uses.

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Projects Inspection Report (Saudi Aramco Form 8213-ENG) (Cont'd)

Figure 15. Completed Projects Inspection Report, SAF 8213-ENG

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Projects Inspection Report (Saudi Aramco Form 8213-ENG) (Cont'd)

Always identify second and succeeding pages. Use another original form for the subsequent pages. Enter this minimum of information on subsequent pages of the report:

◊ Bl/JO number

◊ Report number

◊ Project title

◊ Plant number and/or equipment number

◊ Date of the inspection

Identify the subsequent pages by numbering them with the next consecutive number and also the total number of pages. For example, for a 5-page report, you number subsequent pages as Page 2 of 5, 3 of 5, 4 of 5 and 5 of 5.

Laboratory Testing Forms

When specimens and core samples are sent to the laboratory for the jobsite, you may use the laboratory form, SAF 8563 to include your portion of the required information. The laboratory will return the forms with the results of the cylinder tests indicated in the bottom portion of the form.

You are required only to provide the information about the specimens on this form. Use Work Aid 4C to assist you in completing this form.

Water quality test may be required for the curing water. If you have any doubts as to the quality of the water, send a sample to the laboratory for testing. When submitting the sample of water for testing, use the laboratory request form. Follow the instructions in Work Aid 4D to complete the form. The results will be returned on the form as shown in Addendum 2.

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Laboratory Testing Forms (Cont'd)

Figure 16. SAF 8563, Field Test Report of Portland Cement Concrete

50

CVL 301.05 (SAP ID 40009511)PARTICIPANT EXERCISES

EXERCISE 1. INSPECTING THE CONCRETE FINISHING

Multiple Choice:

Circle the letter indicating the best answer.

1. What is the primary purpose of finishing concrete?

A. Assists in curing

B. Helps get rid of the bleed water

C. Makes the concrete harder

D. Gives the required surface

2. When does the finishing of concrete start?

A. After the concrete is placed

B. Before bleed water is gone

C. Before the forms are removed

D. When the concrete starts to harden

3. When do the plans require only a rough, uniform finish?

A. When the concrete is used for heavy foot traffic.

B. When the concrete is used in industrial.

C. When the concrete will have a topping.

D. When the concrete will be tiled.

4. When would the plan call for a non-skid finish of the concrete?

A. When the concrete is used for heavy foot traffic.

B. When the concrete is used in industrial.

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C. When the concrete will have a topping.

D. When the concrete will be tiled.

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EXERCISE 1. INSPECTING THE CONCRETE FINISHING (CONT'D)

Multiple Choice:


5. To what tolerances must workers finish floors and slabs?

A. 1/16" for every 5'

B. 3/16" for every 10'

C. 1/16" for every 10'

D. 3/16" for every 20'

6. Which of the following flatness and level numbers indicate the most flat and level floor profile?

A. 50, 13

B. 20, 20

C. 15, 30

D. 50, 30

7. Which of the following types of finish is not one of the three major types of formed finish?

A. Cork float finish

B. Matched sample finish

C. As-cast finish

D. Rubbed finish

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Multiple Choice:


8. Which of the following tools is not used during the leveling portion of the finish work?

A. Screed

B. Bull float

C. Steel trowel

D. Darby

9. When using the trowel on the first troweling, how is the troweling done?

A. While the bleed water is till present and the trowel is held at an angle to the concrete.

B. As soon as the surface is floated and the trowel is held flat against the surface.

C. After the concrete has hardened and the blade is held flat as possible against the surface.

D. As soon as the surface is floated and the trowel is held at an angle to the surface.

10. After the first troweling, successive troweling are done in which of the following ways?

A. A slight angle of the blade to the surface with a larger blade each time.

B. The blade is flat to the surface using a smaller blade each time.

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C. The blade is at an angle to the surface with a similar blade each time.

D. The blade is flat to the surface with a smaller blade each time.

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The following situations pertain to the finishing of concrete. Inspection findings are given. Write your conclusions (what is wrong) and recommendations (actions taken). If the procedure is correct, write "This is the correct procedure," in "Conclusions" and "No action is required" in "Recommendations."

11. Findings: Workers are removing formwork as soon as the workers finish the concrete.

Conclusions:

Recommendations:

12. Findings: Workers are finishing the surface with bleed water present.

Conclusions:

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Recommendations:

57



The following situations pertain to the finishing of concrete. Inspection findings are given. Write your conclusions (what is wrong) and recommendations (actions taken). If the procedure is correct, write "This is the correct procedure," in "Conclusions" and "No action is required" in "Recommendations."

13. Findings: Workers are finishing the concrete after it has hardened.

Conclusions:

Recommendations:

14. Findings: You suspect that water used in the curing process is contaminated.

Conclusions:

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Recommendations:

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EXERCISE 2. INSPECTING THE CONCRETE CURING

Multiple Choice:


1. What is the primary purpose of curing concrete?

A. Giving it a good appearance.

B. Helps get rid of the bleed water

C. Makes the concrete harder

D. Gives the concrete good strength and durability

2. What is the primary concern in curing concrete?

A. The proper curing time

B. The proper strength of the concrete

C. Sufficient water for hydration

D. Sufficient setting time

3. Which of the following is not a good curing method?

A. Alternate wetting and drying

B. Direct application of water

C. Ponding

D. Sealing

4. What is the minimum requirement for curing duration?

A. 70% of specified strength

B. 80% of specified strength

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C. 90% of specified strength

D. Not less than 7 days

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EXERCISE 2. INSPECTING THE CONCRETE CURING (CONT'D)

Multiple Choice:


5. In comparing properly wetted concrete to dry-cured concrete, what would be the strength difference after one year?

A. The dry-cured concrete is 20% stronger than the wet.

B. The wet is 50% stronger that the dry-cured concrete.

C. The wet is 2x as strong as the dry-cured concrete.

D. There is little difference after one year.

6. Which of the following would be the nest temperature for curing concrete?

A. 30ºC

B. 90ºC

C. 35ºC

D. 25ºC

7. Which of the following is correct concerning the curing temperature and the amount of water required per pound of air to maintain 100% humidity?

A. At 30ºF, 0.016 pounds of water is required

B. At 140ºF, 0.25 pounds of water is required

C. At 60ºC, 0.22 pounds of water is required

D. At 180ºF, 1 pound of water is required

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EXERCISE 2. INSPECTING THE CONCRETE CURING (CONT'D)

Multiple Choice:


8. When is it safe for the workers to apply a curing compound?

A. When the bleed water is gone

B. Before finishing

C. When concrete has initially hardened

D. After forms are removed

9. Which of the following type of curing compound has dye?

A. Type 1

B. Type 1-D

C. Type 2

D. Type 2-B

10. What must workers do if it is necessary to walk on new concrete while it is curing?

A. Spray it with curing compound

B. Sprinkle washed sand on the surface

C. Use planking to walk on

D. Cover with plastic and walk on the plastic

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EXERCISE 3. PERFORM TESTS FOR HARDENED CONCRETE

Multiple Choice:


1. What is the relationship to the diameter of the core sample and the size of the MSA?

A. There is no relationship.

B. The diameter of the core sample should be the size of the MSA.

C. The diameter of the core sample should twice the size of the MSA.

D. The diameter of the core sample should ten times the size of the MSA.

2. What ASTM would you refer to for information about concrete core samples for testing?

A. ASTM C 171

B. ASTM C 900

C. ASTM D 516

D. ASTM C 42

3. What should be the ratio of the length of the core to the diameter?

A. 1:2

B. 2:1

C. 1:1

D. 2:3

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EXERCISE 3. PERFORM TESTS FOR HARDENED CONCRETE (CONT'D)

Multiple Choice:


4. What is the required total cubic measurement of a broken concrete sample for MSA of one or more inches?

A. 1 cu ft

B. 1 cu yd

C. 1 cu m

D. 100 cu cm

5. What ASTM coves embedded inserts used for strength testing hardened concrete?

A. ASTM C 171

B. ASTM C 309

C. ASTM C 683

D. ASTM C 900

6. What activates the Swiss hammer?

A. A spring

B. A plunger

C. A cartridge

D. An air gun

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EXERCISE 3. PERFORM TESTS FOR HARDENED CONCRETE (CONT'D)

Multiple Choice:


7. What activates the Windsor probe?

A. A spring

B. A plunger

C. A cartridge

D. An air gun

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EXERCISE 4. DOCUMENT INSPECTION RESULTS

For this exercise, refer to problems 11, 12, 13 and 14 in Exercise 1. As specified in this exercise, use those findings to complete the required forms. Use the data below to fill out the headings.

◊ Use today's date

◊ Use your own name

◊ Use your organization and phone number

◊ There is no Job File located in the main office

◊ The address for the Projects Inspection Section is Box 5290, Abqaiq. The FAX number is 572-1094

◊ The addressee (To) is the Project Engineer. His address is P.O. Box 12, Abqaiq

◊ The BI/JO No. is 9201/21001

◊ The Report No. is SAPIS/123/92

◊ The Project Title is the Abqaiq Dining Hall Addition

◊ The Job Location is Abqaiq Dining Hall Patio

◊ Your Supervisor is Mr. Cain. His telephone no. is 874-1122.

◊ You took 5 core samples on the concrete 14 days from the time you did your first notebook entry on finishing concrete.

◊ You took 3 samples of broken concrete for additional tests.

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EXERCISE 4. DOCUMENT INSPECTION RESULTS (CONT'D)

Exercise 4A. Make Field Notes in Field Notebook

For each of the entries in problems 11, 12, 13 and 14, make a field notebook entry.

Exercise 4B. Complete the Proper Document of the Inspection Findings

Using the information in the data section and the requirements given in Exercise 4A, make the proper entries and fill out the proper inspection document according to the data given.

Exercise 4C. Complete Saudi Aramco Form 8563

For the core samples and broken concrete specimens you took, complete a Saudi Aramco form 8563.

Exercise 4D. Complete a Laboratory Request Form

For the water samples you took in problem 14, complete a Laboratory Request Form. State specifically what the water is to be tested for. Include any chemical compounds or materials that might be detrimental to concrete curing as specified in the information section of this module.

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CVL 301.05 (SAP ID 40009511)PARTICIPANT WORK AIDS

WORK AID 1. HOW TO INSPECT THE CONCRETE FINISHING

Use this checklist as a memory aid to help you inspect the finishing of concrete. A checklist is only an aid. For specific instructions, procedures and specifications, always consult the applicable standard(s).

Place a check mark () or () by items as you check them. Mark items N/A, if they do not apply. Consider unsatisfactory all items you did not check, which are not marked N/A. List these items in your inspection report, including recommendations, corrective action and applicable standards.

Verify that the bleed water is gone from the concrete surface before

finishing work begins so that crazing will not occur in the hardened

concrete.

Verify that the workers do not perform excessive early troweling

which may result in crazing.

Verify that the workers do not spread dry cement on concrete that

is too wet to trowel.

Verify that the workers do not sprinkle water on concrete that has

become too dry for proper finishing.

Verify that the workers do not perform any finish operation, such as

screeding, floating or troweling while bleed water is on the surface.

Verify that the workers do not trowel concrete that has hardened.

(Troweling of a surface that has hardened will result indiscoloration.)

Verify that the workers remove the forms only when the timing is

correct. (Premature removal of forms will result in tearing and

spalling of the exterior surface of the construction.)

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Verify that bleed water is only removed through evaporation.

(Fans may be used to assist in some cases.)

Verify that workers keep to a minimum the amount of finishing

necessary to produce the required surface.

Verify that the workers do not over manipulate the fresh concrete

during finishing.

Using a surveyor's instrument, verify that the finish meets the

specifications and tolerances as noted on the design drawing and

industry standards.

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WORK AID 2. HOW TO INSPECT THE CONCRETE CURING



Verify that the workers maintain a sufficient supply of water to the

concrete at all times. Do not allow continuous wetting and drying.

Verify that the workers maintain the optimum temperature range for

the concrete immediately after placing and during finishing.

Verify that the workers keep the concrete at a moderatetemperature during curing to assure its strength.

When used, verify that the workers do not apply any curing

compound until the concrete has initially hardened.

When used, verify that the workers tightly secure the polyethylene

sheeting to prevent the wind from blowing under the plastic cover.

If workmen will be moving about on the concrete during the curing

periods, verify that they use wet washed sand or sawdust to protect

the concrete from abrasion. In this case, do not allow the use of

curing compound.

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Verify that the workers use every effort to keep the concrete wet

and within a temperature of 50ºF to 80ºF

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WORK AID 3. HOW TO PERFORM TEST ON HARDENED CONCRETE



Sampling Hardened Concrete

Core Sampling

Review ASTM C 42 prior to taking samples.

Check the core drill to ensure it is in good working condition.

Ensure that samples taken are representative of the portion of the

hardened concrete to be tested.

Ensure that the diameter of the core is at least twice the size of the

average MSA in the concrete.

Avoid drilling through embedded items, if possible.

If possible, identify the batch number where the samples are taken

and take the sample in the middle portion of that pour.

If at all possible, ensure that the length-to-diameter ratio is at least

2:1.

Ensure that cores with a length of less than 95% of the diameter

are not used for compressive strength test.

Check the surface appearance and the best approach route for

core samples for purposes other than strength test.

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Do not use core samples for moisture test when the samples are

taken with drills that use water for cooling and lubrication.

Do not allow cores that are used for test requiring boiling to be

used for strength test.

Document the collection of core samples in the proper forms and

complete the proper forms for the laboratory. Be sure to make entry

in the logbook of inspection report form.

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WORK AID 3. HOW TO PERFORM TEST ON HARDENED CONCRETE (CONT'D)




Broken Concrete Samples

Ensure that the broken concrete samples are representative of the

area requiring testing.

For MSA of 1" size or more, ensure that total sample measures

1 cubic foot.

Label and identify each sample with the proper information.

Place each sample in a different bag or box with padding.

If moisture content is to be tested, place the samples in amoisture proof plastic bag.

Document the collection of broken concrete samples in the proper

forms and complete the proper forms for the laboratory. Be sure to

make entry in the logbook or inspection report form.

Onsite Tests for Hardened Concrete

In-place Strength Testing

Review ASTM C 900 before conducting in-place strength testing.

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When use for strength tests, ensure that embedded inserts are

properly placed in the concrete when poured.

When used for strength tests, ensure that drilled inserts are

inserted into the proper size hole.

Determine and record the results of the tests on the proper forms.

Make the proper entries in the logbook or inspection report form.

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WORK AID 3. HOW TO PERFORM TEST ON HARDENED CONCRETE (CONT'D)



Onsite Tests for Hardened Concrete (Cont'd)

Nondestructive Strength Testing (Cont’d)

Review modules CVL 101.08 and 200.02 before performing these tests.

Ensure that the Swiss hammer or the Windsor probe is in good working

order and is properly calibrated.

If using the Swiss hammer, take about 15 readings in each location and

average the 10 that are closest to each other. This is the reading for that

area.

If using the Windsor probe, follow the directions in the manufacturer's

instructions for the number of tests required in each location.

Warning: If the Windsor probe is used, ensure that it is used safely in accordance with the manufacturer’s instructions. It uses a powder-filled cartridge (like a blank cartridge used in a gun). It is very powerful and can be deadly at close range. Do not

77


point it at yourself or anyone else while it is in use.

Determine and record the results of the tests on the proper forms.

Make the proper entries in the logbook or inspection report form.

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WORK AID 4. HOW TO DOCUMENT THE INSPECTION RESULTS

Use the following information to help you document the results of your inspection.

1. Make a detailed field notes as you conduct your inspection.

2. After completing your inspection, make an entry into the Job Site Logbook or Project Inspection Report (PIR). Give specific details about the items you found which need correcting.

3. If action is taken on logbook or inspection report items within reasonable time, complete a Projects Inspection Non-Conformance Report (SAF 8213-ENG). Most inspectors consider two weeks to be more than reasonable.

4. If action not taken to clear deficiencies after Projects Inspection Non-Conformance Report is issued, complete a Projects Inspection Worksheet(SAF 8213-1A-ENG).

5. For sending concrete core specimens and broken concrete samples to the laboratory for testing, use SAF 8563, Field Test Report of Portland Cement Concrete.

6. For sending water samples to the laboratory for sampling, use SAF 2325, Laboratory Report Form.

7. Use the appropriate work aid to complete the required forms.

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WORK AID 4. HOW TO DOCUMENT THE INSPECTION RESULTS (CONT'D)

Work Aid 4A. Make Field Notes in a Field Logbook

This Work Aid will assist you in developing inspection field notes for future reporting. Follow the steps that apply to inspection items and record in your field notebook. Some items may not immediately apply.

STEP INFORMATION REQUIRED ENTRY REQUIRED

1. Date and Time Date of inspection and time of day the inspection began

2. Location / Plant No. Exact location where inspection was performed and plant number

3. Equipment Description Brief description of equipment to be inspected

4. Material / Thickness/Size Identify the material and thickness/size of the specimen

5. Standards / Codes Applicable codes and standards

6. Tm Limits / Type of Inspection

Identify minimum thickness of equipment, if applicable and type on inspection performed, e.g., VT, PT, MT, etc.

7. Inspection Equipment Used Tools and equipment used during inspection

8. Reason/Purpose of Inspection

Purpose of the inspection

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9. Contact Person / Phone No. People to contact and their phone numbers

10. Findings Discrepancies found during inspection

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Work Aid 4A. Make Field Notes in a Field Logbook (Cont'd)

This Work Aid will assist you in developing inspection field notes for future reporting. Follow the steps that apply to inspection items and record in your field notebook. Some items may not immediately apply.

11. Conclusions Inspector's decisions about the deficiency and cause

12. Recommendations Inspector's solution to the problem

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Work Aid 4A. How to Write Field Notes (Cont'd)

Figure 17. Numbered sample of field note sheet

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Work Aid 4B. Make Entries in the Site Logbook

This Work Aid is a checklist that will assist you in documenting the Projects Inspection Logbook. Follow the steps in the following and enter the data required as indicated in the block entitled "Entry Required." Operations Inspection Logbook entries are normally made once you have made your field notes.

STEP INFORMATION REQUIRED ENTRY REQUIRED

1. Date/Log# Enter date (month/day/year) and log number

2. Inspection Comments Identify the type of inspection, the discrepancies and the standard/code it violates. Sign and date

3. Inspection Sign-Off Date Sign and date when job is completed satisfactorily

Note: Include the work order number once it has been assigned.

Note: Enter closing remarks when the job is completed satisfactorily. Always sign legibly.

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Work Aid 4B. Make Entries in the Site Logbook (Cont'd)

Figure 18. Completed inspection logbook entries with numbered blocks

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Work Aid 4C. How to Complete a Projects Inspection Report (PIR)

Use this Work Aid as a checklist to make entries on a Projects Inspection Report (PIR) form. Refer with the completed form in Figure 19.

STEP INFORMATION TITLE ENTRY REQUIRED

1. Section Words to identify your unit

2. Address The address of your unit

3. To: The name of addressee (the person who will get this report)

4. Address Address of the addressee

5. BI/JO No. Budget item/job order number

6. Project Title Title of the project such as,AIN DAR WIP-1, NEW PIPING

7. Report No. Next consecutive number provided by the unit clerk

8. Job Location Location of the site inspection took place. Use only allowedabbreviations

9. Plant No./Equip. No. Number of the plant or equipment number

10. Date of Inspection Date the inspection was started

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11. Scope The main topic

12. Finding(s) Discrepancies found during the inspection

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Work Aid 4C. How to Complete a Projects Inspection Report (PIR) (Cont'd)

Use this Work Aid as a checklist to make entries on a Projects Inspection Report (PIR) form. Refer with the completed form in Figure 19.

STEP INFORMATION TITLE ENTRY REQUIRED

13. Recommendation Necessary action required based n finding(s)

14. cc: Distribution

15. Inspector Your name

16. Date Date you sign the form, day/month/year

17. Telephone number Your telephone number

18. Signature You sign your name legibly

Note: Identify second and succeeding pages with a minimum of information as explained in the Information Sheet. Use another original form for the next page.

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Work Aid 4C. How to Complete a Projects Inspection Report (PIR) (Cont'd)

Figure 19. Completed Projects Inspection Report

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CVL 301.05 (SAP ID 40009511)PARTICIPANT GLOSSARY

GLOSSARYACI Abbreviation for the American Concrete

Institute

aggregate Sand or a combination of sand and small gravel use in mixing cement, mortar and grout.

ambient temperature The prevailing or existing atmospheric temperature and measured using either a Centigrade or a Fahrenheit thermometer.

ASTM Abbreviation for the American Society for Testing and Materials

bleed water Surplus water in concrete that rises to the surface after screeding and leveling has been completed. This is caused by the weight of the particles in the mix pushing downward, forcing the water upward and outward.

bull float A hand-held tool resembling a large broom with a long handle for leveling and smoothing out wet concrete.

compressive strength The ability of concrete to support a load; measured in pounds per square inch (psi) or megapascals (MPa)

crazing Hairline cracks in the surface of newly hardened concrete caused by surface shrinkage.

crown A high spot in the middle of a slab of concrete so that water will drain off toward each side of the slab.

curing The time period immediately after mixing when concrete begins to harden.

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finishing The phase of concrete placement manipulating the surface texture.

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GLOSSARY (CONT'D)flatness An analysis of the elevation differences

for a slab of concrete. You determine the data by measuring the surface at 12 inch intervals and comparing it with the Floor Finish Tolerances specified in ACI 117 standards.

formed surfaces Surfaces of concrete that are finished or treated to improve appearance, serviceability, or watertightness.

fresh condition The first stage of newly-mixed concrete.

green concrete Newly-poured concrete still having a high amount of water until full curing has taken place.

honeycomb A defect occurring when concrete paste does not completely fill the space between the coarse aggregate particles.

hydration The reaction of water with an object to form a new compound, such as mixing water with a cement mixture (burnt gypsum and lime) to make concrete.

levelness A factor you determine by taking consecutive measurements of elevation differences on a slab of concrete at 10 ft intervals.

mechanical vibrator A motorized device, usually hand-held, for consolidating freshly-poured concrete.

mortar A mixture of cement, water, sand and aggregates that is smaller than 1/4 inch in size.

MSA A thin filler cement used to strengthen block wall.

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opaque Having the ability to block radiant energy, particularly light

placed concrete Wet concrete that has been placed using a pneumatic pump and hose.

profilometer A calibrated Instrument for measuring the levelness for a slab of concrete.

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GLOSSARY (CONT'D)rebound hammer test A surface hardness test performed

on concrete using a Schmidt or Swiss hammer.

scaling Where the surface of hardened concrete slab breaks away for the rest of the slab to a depth of about 1/8 inch.

screeding A process requiring two workers using a 2" x 4" piece of lumber to skim and level the top surface of wet concrete.

tolerance A measurable range of variation for concrete surface texture usually specified on construction plan sheets.

transparent Having the properties to let light to pass through the surface.

uniformed surfaces Surfaces of concrete that require a minimum of finish for acceptability.

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CVL 301.05 (SAP ID 40009511)PARTICIPANT ADDENDUM

ADDENDUM A

SAEP-1150

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ADDENDUM B

SAES-Q-001

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ADDENDUM C

ACI 117-90

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ADDENDUM D

ACI 308-92

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ADDENDUM E

ASTM C 42

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ADDENDUM F

ASTM C 309

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ADDENDUM G

ASTM C 900

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module 2 cvl 301.05 (p).doc

Documents

complete saudi aramco

concrete curing24description

concrete postpour

hardened concrete62work

chief engineer of saudi

field logbook65work

inspection findings58exercise

site logbook68work aid