PE-ECC梁抗冻融性能试验研究与有限元分析

为研究聚乙烯超高韧性水泥基复合材料梁的抗冻融性能，参照西北地区冬季近10年1月份平均最低温度，对15根PE-ECC梁进行了冻融试验。对冻融后的PE-ECC梁的受弯性能进行了分析；采用基于热传导理论的有限元程序USDFLD对PE-ECC梁进行了冻融循环与荷载耦合作用下的分析，同时与PE-ECC梁的冻融试验结果进行了对比与分析。结果表明，冻融200次后的PE-ECC梁的质量损失率为1.12%，相对动弹性模量高达93.4%，且冻融100次后的PE-ECC梁的极限弯矩约是PVA-ECC梁的1.19倍，是同等级抗压强度普通混凝土梁的1.62倍；ABAQUS子程序USDFLD可以较准确地计算PE-ECC梁在冻融循环作用下的破坏应力、承载力等，得到的PE-ECC梁抗冻融性能与试验结果吻合较好。采用USDFLD程序模拟PE-ECC梁的抗冻融循环性能具有可行性，可为研究荷载作用下的ECC构件的抗冻融循环性能提供一定的参考。

Experimental study and finite elementanalysis on freeze-thaw resistance of PE-ECC beams

In order to study the freeze-thaw resistance of polyethylene engineered cementitious composite (PE-ECC) beams,15 PE-ECC beams were tested with reference to the average lowest temperature in January of recent ten years in winter in Northwest China.The bending properties of PE-ECC beams after freezing and thawing were analyzed.At the same time,the finite element program USDFLD based on heat conduction theory was used to analyze the PE-ECC beam under the coupling action of freeze-thaw cycle and load,and the results were compared and analyzed with the freeze-thaw test results of PE-ECC beam.The results show that the mass loss rate of PE-ECC beam after freezing and thawing for 200 times is 1.12%,the relative dynamic elastic modulus is as high as 93.4%,and the ultimate moment of PE-ECC beam after freezing and thawing for 100 times is about 1.19 times that of PVA-ECC beam and 1.62 times that of ordinary concrete beam with the same compressive strength.ABAQUS subroutine USDFLD can accurately calculate the failure stress and bearing capacity of PE-ECC beams under freeze-thaw cycles.The freeze-thaw resistance of PE-ECC beam is in good agreement with the experimental results.It is possible to use the program USDFLD for simulating the freeze-thaw resistance of PE-ECC beams,which provides some reference for the study of the freeze-thaw cycle resistance of ECC members under loads.