Evaluation of bond strength in Roller Compacted Concrete under various normal pressures

Abstract

The construction of dams using Roller Compacted Concrete (RCC) is a relatively new technology, which has rapidly developed in recent years. To increase the safety factor in designing the various horizontal construction joints in RCC dams, an experimental research using interlayer cement grout has been carried out to improve the bond strength. A device with the ability of exerting the normal pressure in the direct shear method has been designed and used. 144 tests were carried out to assess the effect of interlayer cement grout along with exerting the normal pressure. The tests include different proportions of water to cement of the interlayer grout (0.5, 0.75, 1) and different values of normal pressure (0, 5, 10, 15 kg/cm2) in the ages of 7, 28 and 90 days. The results indicate that the use of interlayer cement grout in the range of the normal pressure exerted gives higher bond strength compared to the state of no grout. By reducing the ratio of water to cement of the grout, the bond strength increases.