Masonry units can be concrete, clay, or natural stone. The majority of masonry construction today is done with concrete masonry units (CMUs) or clay masonry (brick). These units are manufactured to specific sizes and engineering properties. Uniform sizes means that designers can create walls using modular dimensions and masons can place units quickly. The manufactured units are more consistent and are the easiest to use. The most common specification for concrete masonry is ASTM C 90 and for clay masonry is C 216.

Cement is the key ingredient that binds mortar into a cohesive mass, allowing it to harden into a strong, durable material. It’s possible to use various cements to accomplish this:

• masonry cement (ASTM C 91, CSA A3002)


• mortar cement (ASTM C 1329, CSA A 3002))


• portland cement (ASTM C 150, CSA A3001) and lime (ASTM C 207)

Sand should meet grading requirements outlined in ASTM C 144. These sands have the right range of particle sizes to provide workable mortars when mixed with cement and water.

Other ingredients include water and any optional admixtures. Water must be drinkable, or potable. Admixtures can be used for various purposes. One of the more common admixtures for mortar is a color pigment (ASTM C 979).

Mortars are usually specified by ASTM C 270 or CSA A179. These standards have what are called proportion specifications and property specifications. Proportion specifications are like recipes and property specifications require that testing be done to verify mortar strength. Both methods give acceptable results, but only one method can be selected.

For more information on masonry mortars, see Masonry Mortars (IS040)

Partial list of masonry-related standards available from ASTM and CSA:

ASTM www.astm.org
C 90 Standard Specification for Loadbearing Concrete Masonry Units
C 91 Standard Specification for Masonry Cement
C 144 Standard Specification for Aggregate for Masonry Mortar
C 150 Standard Specification for Portland Cement
C 216 Standard Specification for Facing Brick (Solid Masonry Units Made from Clay or Shale)
C 270 Standard Specification for Mortar for Unit Masonry
C 979 Standard Specification for Pigments for Integrally Colored Concrete
C 1329 Standard Specification for Mortar Cement

CSA www.csa.ca
A3001 Cementitious Materials for Use in Concrete
A3002 Masonry Cement

 
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