Development of Concrete Water Absorption Testing for Quality Control

Concrete durability can be evaluated by a number of properties - such as water absorption and chloride diffusion. Each of these properties can be measured using Standardized methods. Water absorption can be linked to porosity and therefore to eventual deterioration. Tests based on absorption have the potential to be simple and rapid tests for placed concrete. However, it is impossible to provide the Standard conditions for in-situ measurements. Water absorption is strongly affected by environmental temperature and concrete moisture content. These different conditions may cause incorrect evaluation of concrete performance. In this thesis, several samples were taken from three different construction projects in the Montréal region. These samples were taken to the laboratory, conditioned in different relative humidity and temperature environments and later water absorption tests were performed on them to investigate the effect of these two factors. In addition, three samples of each concrete mixture were placed outdoors and were tested in different environmental situations. Lastly, in-situ water absorption tests were performed on real concrete elements for one of the projects in actual field conditions. It was found that the concrete water absorption rate increases linearly with increasing temperature and decreasing moisture content. In addition, surface relative humidity was found as an accurate and practical indicator of concrete moisture content. These relationships were verified by additional exposed and in-situ measurements. It is suggested to perform several water absorption tests along with temperature and concrete surface relative humidity measurements to arrive at a Standardized value for quality control purposes