The pore structure of concrete and its resistance to moisture ingress have a strong impact on the concrete’s durability. There is extensive use of water absorption tests to determine the amount of water that a concrete specimen is capable of absorbing within a specified time when subjected to water. The tests are especially helpful in the comparison of various concrete mixes, curing regimes, and material qualities. The interpretation of the findings is necessary since increased water absorption may be an indication of a greater porosity, and this may result in low strength and low durability. The right interpretation helps in making better choices of the material selection and quality control.
Principle and Methodology
The principle of the water absorption test is based on the weight gain of a dry specimen of the concrete in the water. First, the specimen is dried in the oven to eliminate free moisture content, and then the specimen is weighed to obtain dry mass. This is then placed in water over a certain time period, i.e., 24 hours, and then surface dried and again weighed. The fact that the percentage change in the mass is positive reflects the value of water absorption. This number represents the amount of available pores in the concrete, and it refers to the ease with which water may enter the material.
