CA砂浆力学性能的应变率敏感性及本构关系

Strain Rate Sensitivity and Constitutive Relation of Mechanical Properties of CA Mortar

为研究水泥乳化沥青砂浆(CA砂浆)力学性能的应变率敏感性,采用微机控制电子万能试验机进行了CA砂浆在不同应变率下的应力-应变压缩试验.结果表明,CA砂浆的力学性能随着应变率的增大而增大,裂纹扩展速度的限制、侧向变形的惯性作用及沥青网络结构的横向约束导致了CA砂浆力学性能的应变率敏感性.文中还建立了CA砂浆的应变率本构关系,该本构关系能够精确模拟CA砂浆的峰值强度与弹性模量,整个变形过程中的拟合结果与试验结果的复相关系数均大于0.93.通过对应变率本构关系的敏感性分析可知,应变率越高,CA砂浆的韧性和应变率敏感性越低.

In order to investigate the strain rate sensitivity of the mechanical properties of cement and asphalt mortar（ CA mortar）,the stress-strain compressive experiment of CA mortar at different strain rates was performed by means of a microcomputer-controlling electronic universal testing machine. The results show that the mechanical properties of CA mortar increase with the strain rate,and the strain rate sensitivities are attributed to the limit of the crack propagation velocity,the inertial effect of the lateral deformation and the horizontal restraint of the asphalt network structure. Furthermore,a constitutive relation of strain rates is established. The constitutive relation can accurately stimulate the peak strength and elastic modulus of CA mortar,and the multiple correlation coefficients of the fitting and experimental results in the whole deformation process are both greater than 0. 93. It is also found from the analysis of the sensitivity of constitutive relation that,the higher the strain rate is,the lower the toughness and strain rate sensitivity of CA mortar will be.