ABSORPTION CHARACTERISTICS OF CONCRETE AS A FUNCTION LOCATION RELATIVE TO CASTING POSITION

Three different concrete mixes were prepared, the control mix in which no cement replacement material was added, and mixes where 22% and 9% by weight of cement was replaced with fly ash and silica fume respectively. Mixes were cast in 100mm cube moulds and cured at 20 degrees C and 45 degrees C using a variety of different curing regimes with respect to relative humidity and curing time to simulate concretes in hot and temperate climates. After curing, sliced samples were taken from various locations (faces) of the cube to determine their absorption. Two methods were used to study the absorption characteristics, the shallow immersion and the capillary rise. A large variation in absorption values existed between the upper surface during casting of the concrete cubes, the base and the sides. The absorption value of the complete unsectioned cube (100 mm) is similar to that of sectioned side face. A near-linear relationship exists between the two absorption methods.