Module 5 Masonry Mortars
Colorants
Made of mineral oxides, added to masonry cements to obtain a desire mortar color.
Pre-blended mortars
Prepared by manufacturers with all ingredients except water. Are mixed and ground together based on ASTM C270 standard proportions.
Workability
a measure of the ease with which the mortar can be mixed placed, and finished
Bond strength
a measure of the resistance to separation of mortar and masonry units
Mortar
a mixture of cementitious materials , sand , and water that bonds individual brick or concrete masonry units to create masonry walls
Masonry cements
a mixture of portland or blended hydraulic cement (a cement that hardens under water) and plasticizing materials (materials such as limestone , hydrated or hydrated or hydraulic lime intended to enhance workability)whose air content varies widely between manufactures and are recognized for their good workability
Elasticity
a property of mortar that enables it to retain its original size and shape after compaction
Autogeneous healing
a unique characteristics of lime-based mortars that have the capability by chemical reaction to fill small voids that may occur in the joints
Air-entraining agents
additives increasing the air content in cement
Admixtures
additives that Increase workability, strength, and weather resistance. Also add color.
Plasticizer
adds workability to mortar
Accelerators
admixtures that increase the masonry cement's rate of hydration
plasticizers
admixtures that result in mortars that are easier to spread and that adhere to the towel and masonry units better
Retempering
also called tempering the process of adding water to the mortar to replace water lost by evaporation
Hydrated lime
sets upon contact with the air
Mortar cements
similar to propriety masonry cements except they have lower air content and include a minimum flexural bond strength requirement
Flexural strength
the measure of a material's capability to the withstand bending
Tensile strength
the measure of material's capability to withstand stretching
Extent of Bond
Depends on the properties of the mortar and the bonding surface.
Sand
The least expensive ingredient in mortar, and is used as a filler.
Air-entraining
This admixture is commonly added to reduce the water content in mortar.
Set accelerator
decreases the time needed for mortar to harden