The effect of mechanical stress on permeablityof concrete : A review

The presence of aggressive fluids and their transport is by far the most important factor controlling the durability of cement based composites. In structural concrete, the application of mechanical stress leads to cracking, which in turn affects the transport properties adversely, but very little is known of this influence. The paper highlights the vast discrepancy between experimentally determined permeability data, which appear to be largely artifacts of disparate test procedures. In particular, it is not clear if an equilibrium was attained in the fluid flow and further, whether the flow measurements were made in the presence of the applied stress, which together make it very difficult to compare experimental data. Nevertheless it is clear that stress induced cracking leads to a surge in fluid flow and there exists a threshold value for both the applied stress and the resultant crack width associated with fluid permeability in concrete.