氯盐环境下聚丙烯纤维陶粒混凝土冻融损伤模型试验研究

Experimental research on freeze-thaw damage model of polypropylene fibre ceramsite concrete in chloride environment

研究了聚丙烯纤维掺量为0、0.8、1.0、1.2 kg/m^3的陶粒混凝土冻融后的抗冻性能及力学性能。结果表明:随着冻融循环次数增加,纤维陶粒混凝土的相对动弹性模量、抗压强度、劈裂抗拉强度均逐渐降低,掺加聚丙烯纤维可有效提高陶粒混凝土的抗冻性能;从相对动弹性模量、抗压强度指标分析,纤维掺量为1.0 kg/m^3时陶粒混凝土的抗冻性能较好;从劈裂抗拉强度指标分析,纤维掺量为0.8 kg/m^3时陶粒混凝土具有较好的延性;根据抗冻性能衰减规律建立了纤维陶粒混凝土的指数型冻融损伤模型,利用实验数据拟合得到了不同纤维掺量的冻融损伤方程。

The frost resistance and mechanical properties of ceramsite concrete with polypropylene fiber content of 0,0.8 kg/m^3,1.0 kg/m^3 and 1.2 kg/m^3 after freeze-thaw were tested,and the following conclusions were drawn:With the increase of freeze-thaw cycles,the relative dynamic elastic modulus,compressive strength and splitting tensile strength of fiber-reinforced ceramsite concrete gradually degenerate,and the addition of polypropylene fiber can effectively improve the frost resistance of ceramsite concrete. Ac-cording to the analysis of the index of dynamic elastic modulus and compressive strength,the frost resistance of ceramsite concrete is optimum when the content of fiber is 1.0 kg/m^3,and the splitting tensile strength index shows that the ceramsite concrete has better ductility content when the fiber content is 0.8 kg/m^3. An exponential freeze-thaw damage model of fiber ceramsite concrete is established according to the attenuation law of freeze-thaw resistance. The freeze-thaw damage equation of different fiber content is obtained by fitting the experimental data.