砂浆塑性收缩开裂本构方程不可量化因素初探

Preliminary Research on Unquantifiable Factors of Constitutive Equation of Plastic Shrinkage Cracking for Cement Mortar

摘要:

采用自行设计的塑性抗拉强度及塑性毛细管收缩应力测试装置,通过方差分析研究了水泥强度等级、高分子纤维品种对于砂浆塑性收缩开裂本构方程影响的显著性；采用“甄别分处”方法分别研究了水泥品种、骨料品种以及高分子纤维品种能否纳入前期已经建立的砂浆塑性收缩开裂本构方程.结果表明:方差分析只能判断出水泥强度等级、高分子纤维品种对于塑性收缩开裂本构方程影响不显著,并不能将上述不可量化因素纳入本构方程中；采用“甄别分处”方法研究不可量化因素是可行的.采用硅酸盐水泥、复合硅酸盐水泥、铝酸盐水泥、硫铝酸盐水泥、机制砂、MPH 1b纤维时,砂浆抗裂指数实测值和理论值的相对误差分别为725%,507%,7609%,67319%，3116%和652%.可认为硅酸盐水泥、复合硅酸盐水泥、MPH 1b纤维可以纳入前期已经建立的本构方程；铝酸盐水泥、硫铝酸盐水泥、机制砂不可以纳入前期已经建立的本构方程,需要另行建立新的本构方程.

Abstract:

The significance of the influence of strength grade of cement and kind of polymer fiber on constitutive equation of plastic shrinkage cracking for cement mortar by variance analysis was studied by using a self designed measuring device. By using the method of “comparison and classification”, serials of experiments were made to make sure whether some unquantifiable factors could be accepted in the constitutive equation of plastic shrinkage cracking by comparing the experimental values and the calculated values with the constitutive equations built before. The results show that by using variance analysis the influence of strength grade of cement and kind of polymer fiber on the constitutive equations isnt remarkable, but strength grade of cement and kind of polymer fiber cant be accepted in the constitutive equation. Preliminary research shows that the method of “comparison and classification” can be used to make sure whether the unquantifiable factors can be accepted in the constitutive equation. T relative errors between the experimental values and the calculated values for Portland cement, composite cement, aluminate cement, sulpho aluminate cement, machine made sand and MPH 1b fiber are 725%,507%,7609%,67319%,3116% and 652% respectively. This indicates that the unquantifiable factors of Portland cement, composite cement and MPH 1b fiber can be accepted in the constitutive equation of plastic shrinkage cracking, whereas aluminate cement, sulpho aluminate cement and machine made sand cant be accepted and its necessary to build a new constitutive equation for them.