碳纤维再生混凝土循环受压性能及本构关系研究

Cyclic Compression Performance and Constitutive Relationship of Carbon Fiber Recycled Aggregate Concrete

为了研究循环荷载下碳纤维再生混凝土(CFRAC)的受压性能,以再生粗骨料取代率、碳纤维体积掺量和加载速率作为变化参数,设计并制作了40个圆柱体试件进行循环受压加载试验。试验观察了试件的破坏形态,获取了应力-应变曲线,分析了不同变化参数对峰值应力、峰值应变、塑性应变、刚度退化和应力退化等性能的影响规律。结果表明:碳纤维再生混凝土试件在循环荷载作用下主要发生脆性破坏;碳纤维改善了再生混凝土的循环受压性能,与未掺碳纤维混凝土相比,当碳纤维体积掺量为0.3%时,峰值应力和峰值应变分别提高了11.33%和12.22%;刚度退化与应力退化程度得到降低;当再生粗骨料取代率为100%时,峰值应力和峰值应变分别提高了10.16%和14.29%;最后,提出了碳纤维再生混凝土在循环受压下应力-应变本构方程。

In order to study the compressive behavior of carbon fiber recycled aggregate concrete(CFRAC)under cyclic loading,40 cylindrical specimens were designed and fabricated for cyclic loading test with recycled coarse aggregate replacement rate,carbon fiber volume content and loading rate as variation parameters.The test observed the failure mode of the specimen,obtained the stress-strain curve,and analyzed the influences of different variation parameters on the mechanical behaviors such as peak stress,peak strain,plastic strain,stiffness degradation and stress degradation.The results show that the carbon fiber recycled aggregate concrete specimens mainly undergo oblique splitting failure under cyclic loading.The incorporation of carbon fiber improves the cyclic compression performance of recycled aggregate concrete.Compared with unmixed carbon fiber concrete,when the volume content of carbon fiber is 0.3%,the peak stress and peak strain increase by 11.33%and 12.22%,respectively.The degree of stiffness degradation and stress degradation is reduced.When the replacement rate of recycled coarse aggregate is 100%,the peak stress and peak strain increase by 10.16%and 14.29%,respectively.Finally,the stress-strain constitutive equation of carbon fiber recycled aggregate concrete under cyclic compression is proposed.