Abstract:According to the problem of plastic shrinkage cracking of cement mortar, based on the flat plate method and the eight word model method, the cement mortar of different water cement ratio and lime soil ratio was changed, and the environmental parameters and polyvinyl alcohol (PVA) fiber parameters were changed to test the plastic tensile strength. Plastic capillary shrinkage stress and water loss evaporation rate were explored by the plastic shrinkage cracking constitutive equation of cement mortar established in the laboratory. The results show that the anti crack index of built up standard mortar is based on the unitary constitutive equation of water loss evaporation rate and the ternary constitutive equation of fiber blending, which can effectively predict the plastic shrinkage cracking of cement mortar in outdoor environment, thus preliminarily establishing early warning mechanism for plastic shrinkage cracking of cement mortar.