Effect of water loading on strength of concrete

The effect of water on concrete compressive strength subjected to triaxial stress was experimentally studied. The cylindrical specimens were 200mm high with diameter 100mm, and the test was carried out by using a static triaxial test machine. The effects of the way of water loading, the confining pressure and the moisture of concrete were taken into account. Two ways of water loading were adopted. In the first way, the confining pressure of water was exerted on specimens mechanically and specimens were sealed to prevent from the penetrating of water. In the second way, specimens were really subjected to water loading and exposed to high water pressure directly. The confining pressure was in the range from 0 to 4 MPa. The tests were carried out both for dry and saturated specimens. The results indicate that under the condition of specimens being sealed, the compressive strength of both dry and saturated concrete under triaxial stress increases obviously with the increase of the mechanical confining pressure, especially for dry concrete. Whereas, under the condition of unsealed the strength of dry concrete decrease remarkably, and the strength of saturated concrete is approximately equal to its uniaxial compressive strength. Furthermore, the mechanism of the interaction between pore pressure of concrete and external loading are demonstrated.