Autogenous shrinkage of cementitious materials at early ages

In this paper, test data of autogenous shrinkage strain of cementitious materials are presented and a prediction model for concrete with water-cement ratio form 0.2 to 0.6 is proposed. Self-stress of concrete, which was caused by external restraint, was measured under different curing conditions; sealed, dried and wet conditions. Influences of mix proportion and restraining ratio on self-stress generation was studied. It was proved that tensile self-stress generation in high-strength concrete was influenced by autogenous shrinkage even in wet condition. The effect of three types of fiber, steel fiber, vinylon fiber and aramid fiber, on self-stress generation in high-strength mortar was investigated. Self-stress due to autogenous shrinkage of mortar was decreased and tensile strength of mortar was increased by addition of the fibers, especially by steel fiber.