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