水泥砂浆封闭孔隙冻胀破坏问题的力学分析  

Mechanical Analysis of Frost Heawing Damage of Closed Pore in Cement Mortar

作　　者：李盛[1] 李建新[1] 王起才[1] 马莉[2] 董朝阳[3] 

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070 [2]兰州工业学院土木工程学院,甘肃兰州730050 [3]兰州铁路局兰州枢纽工程建设指挥部,甘肃兰州730070

出　　处：《公路交通科技》2015年第4期83-89,共7页Journal of Highway and Transportation Research and Development

基　　金：教育部长江学者和创新团队发展计划项目(IRT1139);国家自然科学基金项目(51268032);铁道部科技研究开发计划项目(2010G019-A)

摘　　要：基于热力学平衡原理,利用弹性力学理论,对水饱和状态下中封闭孔隙在结冰压力作用下的孔壁应力进行了力学计算分析。把水泥砂浆中的孔隙形状近似看成是球形或圆柱形,分别建立了细观力学计算模型,并推导了不同孔隙在结冰压力作用下的孔壁内外表面拉应力,并对某一水泥砂浆构件在受冻温度为-20℃时,球形和圆柱形孔隙的孔壁应力进行了计算,结果表明,在相同结冰压作用下,由于球形孔隙较圆柱形受力更为均匀,其孔壁拉应力明显小于圆柱形孔隙,有利于抗冻。最后,依据此理论计算方法,对孔隙形状、半径、孔壁厚度、冻结温度等对孔壁应力的主要影响因素进行了参数分析,以期能够从砂浆入手对混凝土受冻破坏机理做些有益尝试。Based on the thermodynamic equilibrium principle and the elastic mechanics theory, in terms of the cement mortar closed pore under water saturation condition, the mechanical calculation of pore wall stress under the freezing pressure effect is carried out. Regarding the pore configuration in cement mortar as sphere or cylinder approximately, the meso-mechanics calculation models are established respectively. The tensile stress of inside and outside surfaces of pore wall with different pore under the freezing pressure effect is derived, and the pore wall stresses of sphere and cylinder of a cement mortar component at the freezing temperature of -20℃ are calculated. The result shows that due to the stress of the sphere pore is more uniform than that of the cylindrical pore under the same freezing pressure effect, the hole wall tensile stress is much smaller than that of the cylindrical one, it is advantageous to the frost resistant. Finally, according to the theoretic calculation method, parameter analysis are performed to study the main influencing factors on pore wall stress such as pore configuration, radius, borehole thickness and freezing temperature for analysing the cold failure mechanism of concrete from cement mortar.

关 键 词：桥梁工程 水泥砂浆 弹性理论 冻融破坏机理 孔壁应力 孔隙形状 

分 类 号：U445.75[建筑科学—桥梁与隧道工程]