清水及氯盐环境下陶粒混凝土冻融损伤规律试验研究

对掺加1%聚丙烯纤维及未掺纤维的两组陶粒混凝土试件,分别进行了清水冻融和3%NaCl溶液冻融试验,观察了冻融循环后试件的外观变化形态,测试研究了试验过程中试件的相对动弹性模量、质量损失率、剩余抗压强度等损伤量的变化规律。研究结果表明:相同冻融次数时,与清水冻融环境比,氯盐冻融环境下试件的剥蚀和骨料外露现象更明显,相对动弹性模量、质量损失率、剩余抗压强度等指标退化更为严重;掺入聚丙烯纤维可明显改善陶粒混凝土的抗冻性能。分别以相对动弹性模量和剩余抗压强度作为损伤变量,建立了能反映冻融损伤进程的陶粒混凝土冻融损伤模型,参数拟合精度较高。

Experimental Study on the Damage Rule of Ceramsite Concrete under the Environment of Clear Water or Chloride solution

Using two groups of ceramsite concrete specimens with 1%polypropylene fiber and without fiber,freeze-thaw tests in clear water and 3%NaCl solution were carried out respectively to observe the appearance changes of the specimens after freeze-thaw cycles and test the changes of relative dynamic elastic modulus,mass loss rate and residual compressive strength of the specimens during the test process.The results show that the denudation and aggregate exposure are more obvious in chloride salt freeze-thaw environment than in clear water freeze-thaw environment at the same freeze-thaw times,and the degradation of relative dynamic elastic modulus,mass loss rate and residual compressive strength is more serious.The frost resistance of ceramsite concrete can be obviously improved by adding polypropylene fiber.Taking relative dynamic modulus of elasticity and residual compressive strength as damage variables,a freeze-thaw damage model of ceramsite concrete was established,which could reflect the damage process of freeze-thaw,and the parameter fitting accuracy is high.