中强再生混凝土楼板抗弯性能试验研究

Experimental research on moderate strength recycled aggregate concrete floor slabs

为研究中强再生混凝土板的抗弯性能,进行了2个足尺再生混凝土板和2个普通混凝土板的抗弯性能对比试验。试件再生混凝土粗骨料取代率100%、细骨料用天然砂,混凝土设计强度等级均为C40,加载方式为三分点单向重复加载。试验分析了各试件的开裂荷载、屈服荷载、极限荷载、挠度、裂缝及损伤过程。研究表明:中强再生混凝土楼板与中强普通混凝土楼板相比,受弯破坏过程类似,开裂荷载相近、极限荷载较低,跨中挠度略大;中强再生混凝土楼板承载力和正常使用状态下的挠度和裂缝宽度计算可近似采用混凝土结构设计规范的方法,但应乘以与再生粗骨料取代率有关的折减系数,以考虑其长期工作性能与短期试验结果的差异。

To study the flexural performance of moderate- strength recycled concrete slabs,two full- scale moderate- strength recycled concrete slabs and two moderate- strength ordinary concrete slabs flexural performance comparison tests were carried out. Recycled concrete coarse aggregate replacement rate is 100%,and the fine aggregate is natural sand,designed strength of concrete specimens is C40. The loading method was three points one-directional repeat loading. The cracking strength,yielding strength,ultimate strength,deflection,crack and damage process were studied. Results show: comparing with the common moderate- strength concrete floor slab,the flexural failure process and cracking strength of the moderate-strength recycled concrete floor slab are similar and ultimate strength of the moderate- strength recycled concrete floor slab is lower and deflection at mid-span is larger slightly. The calculation of bearing capacity,deflection and crack width of recycled concrete floor slabs at the normal service condition can adopt the method of code for design of concrete structures but reduction factor should be considered according to recycled coarse aggregate rate,in order to consider the difference of the long term behavior and short term test behavior.