纤维混凝土抗盐冻性能试验研究

Research on the Performance of Salt-freezing Resistance for Fiber Cement Concrete

为提高季冻区路用水泥混凝土的抗盐冻性能,以钢纤维、玄武岩纤维、PVA和聚丙烯纤维混凝土和素混凝土为研究对象,进行盐冻条件下的弯拉强度及冻融循环试验,分析200次冻融循环作用下混凝土的弯拉强度损失、相对动弹模量、质量损失及疲劳寿命。研究结果表明:纤维的掺入可显著提高混凝土的弯拉强度(聚丙烯纤维除外)、抗盐冻性能及疲劳性能;钢纤维、玄武岩纤维、PVA和聚丙烯纤维4种纤维掺入后,混凝土的弯拉强度分别比素混凝土弯拉强度增加14.3%、7.9%、20.6%和-4.8%;抗盐冻性能由高到低为聚丙烯纤维>钢纤维>PVA>玄武岩纤维;200次冻融循环作用下,疲劳寿命由大到小为钢纤维>PVA>聚丙烯纤维>玄武岩纤维>素混凝土路面。4种纤维中,钢纤维混凝土弯拉强度和抗盐冻性能良好,且冻融前后疲劳性能最佳,因而在季节性冰冻地区水泥混凝土路面材料设计时应当优先推荐使用钢纤维。

In order to improve the performance of salt-freezing resistance for road cement concrete in season frozen area,the flexural strength and freeze-thaw cycle tests on steel fiber,basalt fiber,PVA and polypropylene fiber concrete and plain concrete are carried out.Then,the flexural strength losses,relative motion modulus,mass loss and fatigue life of cement concrete are studied under 200 times freeze-thaw cycles.The results show that the flexural strength,frost resistance and fatigue performance of concrete are increased significantly with fibers.After the addition of steel fiber,basalt fiber,PVA fiber and polypropylene fiber,the flexural strength of concrete is increased by 14.3%,7.9%,20.6%and-4.8%respectively compared with that of plain concrete.The performance of concrete salt-freezing resistance from high to low is polypropylene fiber>steel fiber>PVA>basalt fiber.Under the 200 freeze-thaw cycles,the fatigue life from big to small is steel fiber>PVA>polypropylene fiber>basalt fiber> plain concrete pavement.Among the four kinds of fibers,the flexural tensile strength and salt-frost resistance for steel fiber is good,and the fatigue performance before and after freezing and thawing is the best,therefore the steel fiber is preferred for the design of cement concrete pavement in seasonal freezing areas.