【摘要】 对聚丙烯纤维混凝土(PFRC)、钢纤维混凝土(SFRC)、普通混凝土(PC)进行冻融循环试验,经过冻融循环后,得到PFRC、SFRC、PC的相对动弹性模量、轴心抗压强度、劈裂抗拉强度,分析冻融循环过程中PFRC、SFRC、PC的冻融损伤率、强度衰减率的演化规律和冻融损伤机理,提出基于Weibull分布的纤维混凝土冻融损伤演化模型,并与推导出的力学性能衰减模型联立得到PFRC、SFRC、PC的相对抗压强度、相对抗拉强度与冻融损伤度的演化模型。结果表明,纤维的掺入能有效减小混凝土的强度衰减和冻融损伤,基于Weibull分布建立的两种冻融损伤模型,可以分别通过冻融循环次数、相对强度预测PFRC、SFRC、PC的冻融损伤度。更多还原

【Abstract】 Freezing-thawing cycle test was carried out on polypropylene fiber reinforced concrete(PFRC), steel fiber reinforced concrete(SFRC), and ordinary concrete(PC). After freeze-thaw cycles, the relative dynamic modulus of elasticity, compressive strength, and tensile strength of PFRC, SFRC, and PC were obtained. The evolution and mechanism of intensity attenuation of PFRC, SFRC and PC in the process of freezing-thawing cycle were analyzed. Based on the Weibull distribution, the fiber concrete freeze-thaw damage evolution model was proposed. The evolution model of relative compressive strength, relative tensile strength freeze-thaw damage degree, and relative dynamic modulus of elasticity of PFRC, SFRC and PC were obtained by combining the deduced attenuation model of mechanical properties. The results show that the strength attenuation and freeze-thaw damage of concrete can be effectively reduced by the addition of fibers. Two freeze-thaw damage models based on the Weibull distribution can be used to predict the freeze-thaw damage degree of PFRC, SFRC, and PC by freeze-thaw cycles and relative strength respectively.更多还原