Term: Mortar (masonry)
**Historical Development of Mortar:**
– Ancient mortars made of mud, clay, and gypsum
– Use of various cement types in the Indus Valley civilization
– Bitumen mortar used in Mohenjo-daro
– Invention of Ordinary Portland Cement Mortar in 1794
– Popularization in the late 19th century
**Types of Mortar:**
– Ordinary Portland Cement Mortar with five standard types
– Strength of Type M mortar
– Polymer Cement Mortar with enhanced properties but higher cost
– Lime Mortar with variations in setting speed and additives
– Pozzolanic Mortar using volcanic ash and lime
**Mortar Composition and Properties:**
– Components include binder, aggregate, and water
– Binders like lime, cement, or their combination
– Role of sand, crushed stone, or gravel as aggregates
– Importance of water for hydration and hardening
– Proportions crucial for strength and durability
**Mortar Dating and Hardening:**
– Radiocarbon dating and Optically stimulated luminescence (OSL) dating
– Mortar dating for insights into construction history
– Hardening process through hydration reaction
– Factors affecting hardening like temperature and humidity
– Proper curing for strength development
**Mortar Applications and Preservation:**
– Use in masonry construction for structural stability
– Joins bricks, stones, or concrete blocks
– Decorative mortar work in historical buildings
– Importance of mortar conservation in heritage structures
– Research on sustainable mortar materials for preservation
Mortar is a workable paste which hardens to bind building blocks such as stones, bricks, and concrete masonry units, to fill and seal the irregular gaps between them, spread the weight of them evenly, and sometimes to add decorative colors or patterns to masonry walls. In its broadest sense, mortar includes pitch, asphalt, and soft mud or clay, as those used between mud bricks, as well as cement mortar. The word "mortar" comes from Old French mortier, "builder's mortar, plaster; bowl for mixing." (13c.).
Cement mortar becomes hard when it cures, resulting in a rigid aggregate structure; however, the mortar functions as a weaker component than the building blocks and serves as the sacrificial element in the masonry, because mortar is easier and less expensive to repair than the building blocks. Bricklayers typically make mortars using a mixture of sand, a binder, and water. The most common binder since the early 20th century is Portland cement, but the ancient binder lime (producing lime mortar) is still used in some specialty new construction. Lime, lime mortar, and gypsum in the form of plaster of Paris are used particularly in the repair and repointing of historic buildings and structures, so that the repair materials will be similar in performance and appearance to the original materials. Several types of cement mortars and additives exist.