What is the difference between sand/lime brick and concrete brick?
Sand/lime or calcium silicate bricks are made with sand aggregate and 5% to 10% hydrated lime and are cured in an autoclave. Properties of these units are specified in ASTM C 73. They are available in severe weathering (SW) and moderate weathering (MW) grades. Concrete bricks, on the other hand, are made with sand aggregate and portland cement. Their properties are specified in ASTM C 55. They are available in Grade N and S. Grade N units have high strength and better resistance to water penetration and frost action. Concrete bricks can be moisture-controlled (Type I) or nonmoisture-controlled (Type II).