高温后型钢再生混凝土梁受弯试验及承载力计算

为揭示高温后型钢再生混凝土(SRRAC)梁的受弯破坏机理,以高温温度和再生粗骨料取代率为变化参数对12个试件进行不同温度作用后(20,200,400,600℃)的静力单调加载试验,观察并获得不同温度后试件的外观变化以及受力破坏过程和形态,获取了荷载-挠度曲线、截面应变分布和极限荷载等重要信息,然后对各变化参数对试件力学性能的影响进行分析。结果表明:高温后型钢再生混凝土梁的受弯破坏形态与常温下基本相同,表现为弯曲破坏、黏结破坏和斜压破坏三种。高温后型钢再生混凝土梁仍具有较好的后期变形性能,但600℃高温后,梁抗弯承载力下降明显,且全再生混凝土梁承载力下降幅度最大。最后给出了高温后型钢再生混凝土梁剩余抗弯承载力的计算方法。

FLEXURAL BEHAVIOR TEST AND BEARING CAPACITY CALCULATION OF STEEL REINFORCED RECYCLED AGGREGATE CONCRETE BEAMS AFTER HIGH TEMPERATURE

In order to reveal the flexural failure mechanism of steel reinforced recycled aggregate concrete( SRRAC)beams after high temperature,twelve SRRAC specimens were designed for monotonic loading experiment at ambient temperature,200,400 and 600 ℃. The experiment involved high temperature and the replacement rate of recycled coarse aggregate. Appearance changes,the failure processes,and forms of specimens at different temperatures were observed,the load-displacement curves, cross-sectional stress distribution, ultimate load and other important information were obtained. And the effecting law of each changing parameter on the SRRAC beams 'mechanical behavior after high temperature was analyzed. Results showed that the failure mode of SRRAC beams after high temperature was similar to that at ambient temperature. The SRRAC beams after temperature had good deformation performance after ultimate load,but the ultimate bearing capacity of beams after 600 ℃ reduced obviously,the bearing capacity of full recycled aggregate concrete beams decreased most seriously. Finally,the residual flexural bearing capacity calculation methods of SRRAC beams after high temperature were proposed.