ABSTRACT
Mortar is a material that is plastic when fresh and then stiffens rapidly when in contact with pieces of stone or brick and sets to a hard adherent mass over a period of days, weeks or longer. The primary purpose of mortar is to fill the gaps between blocks of stone, brick or concrete that result from their imperfect size and shape and thus to make possible the construction of masonry which is structurally stable and weatherproof. If the masonry units are accurate to fractions of a millimetre or selected to dovetail together, as in the case of dry stone walling, it is possible to build structurally stable masonry without mortar. In modern slender brickwork cladding and lightly stressed load-bearing brickwork there is also a requirement for a minimum bond to impart a resistance to lateral loading (flexural resistance).
