水泥砂浆塑性收缩开裂预警机制的初步建立

Preliminary Establishment of Early Warning Mechanism for Plastic Shrinkage Cracking of Cement Mortar

关键词:  水泥砂浆  塑性收缩开裂  本构方程  预警机制  聚乙烯醇纤维

Key words:  cement mortar  plastic shrinkage cracking  constitutive equation  early warning mechanism  polyvinyl alcohol(PVA) fiber

摘要:

针对水泥砂浆塑性收缩开裂的问题，基于平板法和八字模法，分别对不同水灰比和灰砂比的水泥砂浆，改变其环境参数与聚乙烯醇（PVA）纤维参数，测试其塑性抗拉强度、塑性毛细管收缩应力及失水蒸发速率，通过在室内建立的水泥砂浆塑性收缩开裂本构方程，对水泥砂浆塑性收缩开裂预警机制的建立进行了探索.结果表明：室内建立的基准水泥砂浆抗裂指数基于失水蒸发速率的一元本构方程及掺纤维水泥砂浆的三元本构方程可有效预测室外环境下水泥砂浆的塑性收缩开裂，由此初步建立了水泥砂浆塑性收缩开裂预警机制.

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.