冻融循环后水泥基复合材料力学性能的试验研究

EXPERIMENTAL STUDY OF THE MECHANICAL BEHAVIORS OF ECC AFTER FREEZE-THAW CYCLES

为研究工程用水泥基复合材料(ECC)在冻融循环作用后的力学性能,采用快冻快融法对掺入不同类型纤维、不同纤维掺量的试件进行冻融循环试验,研究其在冻融循环作用下质量损失率、纵向相对动弹性模量、立方体抗压强度、抗折强度等力学性能。研究表明:随冻融循环次数增加,试件破坏越严重,质量损失率随冻融循环次数增加而增大,立方体抗压强度和抗折强度随冻融循环次数增加而下降。掺入纤维试件经过冻融循环作用后各方面性能均优于未掺纤维的水泥砂浆试件。体积掺量为2%的日本RECS15×12型PVA纤维的试件性能最好,质量损失率小于2%,纵向相对动弹性模量下降不到30%,且能保持较好的延性,抗冻等级高于F200,能够满足寒冷地区工程需要。

In order to study the performance of ECC after freeze-thaw cycles,rapid freeze-thaw method was used to test specimens with different kind fiber and different admixture amount of fiber. The mass loss ratios,longitudinal relative dynamic elastic modulus,cube compressive strength and flexural strength etc were tested. The results showed that damage to the specimens was more serious with the increasing of freeze-thaw cycle. Mass loss ratio increased with the increasing of freeze-thaw cycle. Cube compressive strength and flexural strength decreased with the increasing of freeze-thaw cycle. The behaviors of specimens with fiber were better than specimens without fiber. Specimens with admixture amount of 2% Japanese RECS15 × 12 PVA fiber had the best behaviors,whose mass loss ratios were less than 2% and longitudinal relative dynamic elastic modulus decreased by less than 30%,and good ductility could be held. So,the frost resistance grade was higher than F200,which could meet the engineering requirements in cold area.