冻融循环下沙漠砂纤维混凝土损伤模型研究

为研究冻融循环作用下沙漠砂纤维混凝土的损伤模型,对沙漠砂纤维混凝土进行0次、25次、50次、75次、100次、125次及150次的快速冻融试验,分析不同冻融循环次数后沙漠砂纤维混凝土相对动弹性模量、抗压强度及劈裂抗拉强度的衰减规律。结合试验数据,基于指数函数和二次函数建立沙漠砂纤维混凝土的冻融损伤劣化模型。结果表明:与沙漠砂混凝土相比,掺入聚丙烯纤维的沙漠砂混凝土的抗冻融能力有效提高;相对动弹性模量随冻融循环次数的增加而下降;与未冻融相比,150次冻融循环后,沙漠砂纤维混凝土的抗压强度降低了49.5%,劈裂抗拉强度降低了70.13%;建立了两种冻融循环下沙漠砂纤维混凝土损伤模型,其计算值与试验值吻合较好,可为沙漠砂纤维混凝土在严寒地区的应用提供理论参考。

Damage Model of Desert Sand Fiber Reinforced Concrete under Freeze-Thaw Cycles

In order to study the damage model of desert sand fiber reinforced concrete under freeze-thaw cycles, the rapid freeze-thaw tests of 0 times, 25 times, 50 times, 75 times, 100 times, 125 times and 150 times were carried out on desert sand fiber concrete. The attenuation law of relative dynamic elastic modulus, compressive strength and splitting tensile strength of desert sand fiber concrete after different freeze-thaw cycles were analyzed. Combined with test data, the freeze-thaw damage deterioration model of desert sand fiber concrete was established based on exponential function and quadratic function. The results show that compared with desert sand concrete, the freeze-thaw resistance of desert sand concrete with polypropylene fiber is effectively improved. With the increase of freeze-thaw cycles, the relative dynamic elastic modulus decreases continuously. After 150 freeze-thaw cycles, the compressive strength and splitting tensile strength of desert sand fiber concrete decrease by 49.5% and 70.13% respectively compared with 0 times freeze-thaw cycle. Two damage models of desert sand fiber concrete under freeze-thaw environment are established, and the calculated values are in good agreement with experimental values, which can provide a theoretical reference for the application of desert sand fiber concrete in severe cold areas.