Crack resistant mechanism of expansive concrete in early ages

This paper explains the mechanism of nonlinear behavior of expansive concrete under tensile stress. Through uni-axial cyclic loading including unloading process, it is proved that tensile stiffness of expansive concrete during unloading gradually decreases when maximum tensile strain applied increases, and that expansive concrete shows remarkable residual tensile strain after unloading. Based on these experimental facts, a new concept is proposed to rationally explain the nonlinear behaviors peculiar to expansive concrete in tension. It is shown that not only increment of tensile strength of concrete due to prestress but also large deformability before cracking greatly contributes to the cracking resistance of chemically prestressed members.