MODELING OF BLEEDING OF CEMENT PASTE AND MORTAR

Existing bleeding models ave unable to explain fully the mechanism of bleeding as the effect of hydration reaction of cement is not consider ed. To understand the effect of hydration on bleeding, compressibility tests were first conducted for cement paste and mortar at different s tages, but all within the first 120 min. Subsequently, bleeding tests were conducted for tall specimens, and, in addition to surface settlem ent, pore pressure and density profiles were also measured. A rheologi cal model is proposed which can account for the effect of hydration on bleeding. This model is implemented in a self-weight consolidation bl eeding model. A number of bleeding tests were conducted and the result s were compared with the predictions. The good agreement shows that th is model is able to explain the bleeding mechanism of cement paste and mortar, including the effect of hydration, better than previous model s.