水泥砂浆塑性收缩开裂多元本构方程的研究

摘要

Based on the cracking plate method and eight modelmethod,the effects of composition parameters and the external enviroment,on plastic shrinkage and cracking of cement mortar,were studied systematically.The multi-constitutive equation of cement mortar cracking-resistance index for water-cement ratio,aggregate-cement ratio,fly ash content,superplasticizer content and water evaporation rate was established.The experimental results show that multi-constitutive equation of cement mortar cracking-resistance index of K=0.208 × 35.3Wc × 3.80Sc× 1.00FA × 9.62P × 0.00608Vwas credible and crack criterion was established credibly.Water evaporation rate had most influence on plastic shrinkage cracking of cement mortar,and fly ash had no obvious effect.In addition,the verification experiment showed that slag can be suitable with the fly ash constitutive relation that had been established by the screening treatment to the non-quantifiable factors of the types of gelling auxiliary materials.%基于平板法和八字模法,系统研究了组成参数和外部环境两因素对水泥砂浆塑性收缩开裂的影响并建立了抗裂指数K关于水灰比Wc、集灰比Sc、粉煤灰掺量FA、减水剂掺量P和失水蒸发速率V的多元本构方程.试验结果表明:建立起水泥砂浆收缩开裂的本构方程K=0.208×35.3Wc×3.80Sc×1.00FA×9.62P×0.00608V,经验证方程可信度高并且建立了可靠的开裂判据;失水蒸发速率对水泥砂浆塑性收缩开裂影响最大,而粉煤灰掺量对其无明显影响;此外,对辅助性胶凝材料种类的不可以量化因素“甄别分处”,得到矿粉可适用已建立的关于粉煤灰的五元方程.