Dating mortar

Lime and gypsum in the form of plaster of Paris are used particularly in the repair and repointing of buildings and structures because it is important the repair materials are similar to the original materials: The type and ratio of the repair mortar is determined by a mortar analysis.

There are several types of cement mortars and additives. Because of a lack of stone and an abundance of clay, Babylonian constructions were of baked brick, using lime or pitch for mortar.

Mortar is a workable paste used to bind building blocks such as stones, bricks, and concrete masonry units together, fill and seal the irregular gaps between them, and sometimes add decorative colors or patterns in masonry walls.

According to Roman Ghirshman, the first evidence of humans using a form of mortar was at the Mehrgarh of Baluchistan in Pakistan, built of sun-dried bricks in 6500 BCE.

The ancient sites of Harappan civilization of third millennium BCE are built with kiln-fired bricks and a gypsum mortar.

Historically, building with concrete and mortar next appeared in Greece. Pozzolanic mortar is a lime based mortar, but is made with an additive of volcanic ash that allows it to be hardened underwater; thus it is known as hydraulic cement.

The excavation of the underground aqueduct of Megara revealed that a reservoir was coated with a pozzolanic mortar 12 mm thick. The Greeks obtained the volcanic ash from the Greek islands Thira and Nisiros, or from the then Greek colony of Dicaearchia (Pozzuoli) near Naples, Italy.

Polymer cement mortars (PCM) are the materials which are made by partially replacing the cement hydrate binders of conventional cement mortar with polymers.