CIVIL ENGINEERING

BUILDING CONSTRUCTION MATERIALS PAPER

MASONRY

KELOMPOK 1

Muhammad Alif Maggalatta 1306388906

Talitha Jauza Utami 1306387134

Daniel Andiga Wibisana 1306437076

CIVIL ENGINEERING DEPARTEMENT

ENGINEERING FACULTY

UNIVERSITAS INDONESIA

DEPOK 2013

MASONRY

I. Introduction

Masonry is a structure that is constructed by laying individual masonry units. These masonry

units, which are either hollow or solid, are bind together by mortar to create the structure.

Masonry unit can be made of different materials such as brick, stone, clay, mud, rock,

concrete, and limestone. To create a structure such as a wall, rows of masonry units are laid

on top of each other. There are also several ways of arranging how the masonry units are

laid. They have different types of bond patterns.

II. Materials

Masonry construction is made up of masonry units, mortar and also reinforcement when

necessary. Just like there are different types of masonry units, there are also different types

of mortar that one can use to build a masonry structure.

1. Masonry Units

Adobe (Sun dried mud blocks): excellent insulating properties for both dwellings and

ovens; home interiors retain heat in winter and stay cool in summer. Construction

using this material has a low strength.

Stone: durable, fireproof, bug proof, and free of moisture. Well-built stone structures

can stand for centuries. Stone is also very attractive, virtually maintenance free and,

with so many different natural colors available, the final appearance is limited only

by the builder’s imagination

Burnt clay bricks: resistant to fire damage, provides superior wind resistance and

moisture control, can be constructed into a veneer, and is naturally energy efficient. It

has been a proven material for over 5,000 years. A downside to using brick is

thatstress can be placed on both the structure and the foundation of your home,

repairs can be expensive, and once you’ve chosen your look, it’s very difficult to

change

Concrete blocks (solid or hollow): offer various possibilities in masonry construction.

They generally provide great compressive strength, and are best suited to structures

with light transverse loading when the cores remain unfilled. Filling some or all of

the cores with concrete or concrete with steel reinforcement (typically rebar) offers

much greater tensile and lateral strength to structures.

Calcium silicate bricks: Low thermal conductivity, rigid & light weight (Density 250

kg/M3), fire resistant, low specific heat, non-corrosive, low maintenance cost, re-

usable, easily cut.

Stucco: highly durable, and like brick and stone and resistant to damage. The main

concern in building with stucco is the possible accumulation of moisture on

downward slopes in the stone.

2. Mortar

Mortar is a homogeneous mixture composed of cement, lime, sand, and water. The

function of mortar in a masonry construction is to bond the individual masonry units

together so that it can resist movement and stress. The bond between mortar and the

masonry units is very important because the strength of the structure depends on it. There

are two main desirable properties of mortar. The first property of mortar is that it dry and

harden in a reasonable time as it gains strength, so that the next row of masonry units can

be laid without excessive movements of the rows bellow because the mortar is still wet.

The second property is that it should have the ability to retain water so that the water

does not damage the masonry units. There are several types of mortars that can be used

as the bonding agent of masonry units. Strong mortar is not always better because if a

mortar that is significantly stronger than the masonry units, it can put excessive stress

and will cause damage to the masonry units. According to ASTM C 270, Standard

Specification for Mortar for Unit Masonry, there are four main types of mortar.

1) Type M Mortar

Has the highest strength (minimum 2500 psi or 17 MPa)

Should be used when high compressive strength is required

Commonly used with stone

Used in structures with extreme lateral force, such as retaining walls

2) Type S Mortar

Medium strength mortar (minimum 1800 psi or 12 MPa).

Used where the masonry is attached to the ground; in making exterior

walls, pavement and shallow retaining walls

Good for resisting pressures from the soil

3) Type N Mortar

Most common type of mortar with medium strength (minimum 750 psi or

5 MPa)

Used for reinforced interior and normal load bearing walls

4) Type O Mortar

Low strength mortar (minimum 350 psi or 2 MPa)

Used for interior non load bearing walls

Used for repair work

Used with masonry units with low compressive strengths

III. Types of Bonding Patterns

English Bond Flemish Bond

Header Bond

Stretcher Bond

Quetta Bond Rat-

Trap Bond

IV. Advantages and

Disadvantages of Masonry

Advantages:

Most type of stone does not require painting and so can provide a structure with reduced

costs.

The use of materials such as brick and stone can protect buildings from fire.

Masonry structures built in compression preferably with lime mortar can have a useful

life of more than 500 years compared to 30 to 100 for structures of steel or reinforced

concrete.

Masonry is a non-flammable product.

Masonry walls are more resistant to projectiles, such as debris from hurricanes or

tornadoes.

Disadvantages:

Combined with appropriate weather conditions can cause degradation of masonry wall

surfaces due to frost damage extreme.

Masonry consists of heavy materials and must be built on a strong foundation to avoid

settling and cracking like concrete.

Masonry construction does not lend itself well to mechanization, and requires more

skilled labor than stick-framing.

V. Maintenance

If the masonry building is constructed properly, the stone wall system will require little

maintenance compared to other wall systems. The service life of the stone could be 100

years or more, depending on the detail and maintenance. The most frequent maintenance is

the regular replacement of sealant in expansion joints, perimeter openings (windows, doors,

etc) and the through wall flashings. The time frame for replacement of sealant depends on

the sealant used, but usually ranges from 7 to 20 years each. Repointing mortar joints in

exterior stone usually takes between 20 to 30 years after installation, depending on the type

and quality of the original stone installation.

VI. Compressive Strength of Mansory

Masonry is designed to resist compressive forces rather than tension forces. Compressive

strength is defined as the maximum force that is resisted per unit of cross sectional area of

masonry (f = P/A). The modulus of Elasticity is found by dividing stress over strain (E =

f/strain).

The graph and table below will show the results of the tests that have been done according to

ASTM C 1314-00a (ASTM 2001b) and IS 1905 (IS 1987). This will show the failure strains

and modulus of Elasticity for masonry prisms that are consist of 4 different types of bricks

grades (Type M, B, O, and S) combined with 3 mortar grades (weak, strong, and

intermediate).

P

P

A

Graph of Stress vs Strain of Brick units, mortar cubes and Masonry prism

The table shows the summary of results including fb (failure strains) and Eb (modulus of Elasticity).

Seven specimens are tested for each type of bricks and the average is calculated for the result of

each brick type. The graph shows a comparison of stress-strain curves for brick units, mortar cubes,

and masonry prisms that have been done in another test. Graph (a) is for the weak mortar grade, (b)

for strong, and (c) for intermediate grade of mortar. According to the graph, the masonry of bricks

behaved linearly. But after about one-third of the ultimate failure load, the graph became nonlinear.

VII. References

http://archtoolbox.com/materials-systems/masonry/126-masonry-mortar-types.html

http://www.constructionknowledge.net/masonry/masonry_masonry.php

http://www.heritagetesting.co.uk/factsheets/calcium-silicate-masonry-brick.html

http://www.cement.org/masonry/ds_techtip_urm.asp