Flexural behaviour of SFRRAC two-way composite slab with different shapes

不同构造形式钢纤维增强再生混凝土双向叠合板受弯性能

To promote the application of green renewable materials in concrete composite slabs(CCSs)and study the flexural behavior of CCSs with different shapes,the bending performances of three CCSs with a SFRRAC base plate,one cast-in-site concrete slab of ordinary concrete and one CCS of ordinary concrete by steel bar truss(as recommended in the technical specification for precast concrete structures in Chinese)were compared through experiments.The carrying capacity,flexural behaviour and bi-directional mechanical properties of the specimens were systematically analyzed from the failure modes,load-deflection curves,load-bar strain curves,load-slip curves and crack distributions.Results show that the bending failure process of CCSs with a SFRRAC base plate is similar to that of the cast-in-site concrete slab of ordinary concrete and CCS of ordinary concrete by steel bar truss,as all of them went through the plastic phase,elastic plastic phase and failure phase with fully developed cracks and deflection.No sudden breakage or horizontal cracking of the connecting interface between the base plate and concrete topping was observed.The shape of the base plate has a major impact on the bearing capacity of the CCS with the SFRRAC base plate.When calculating the ultimate bearing capacity with the plastic yield line theory,the influence of the base plate shape on the plastic yield line position should be taken into account.

为推动绿色再生类材料在叠合楼板中的应用,研究不同构造形式所组成的混凝土叠合板受弯性能异同,开展了3块钢纤维增强再生混凝土双向叠合板、1块普通现浇混凝土双向板及1块《装配式混凝土结构技术规程》推荐的普通混凝土桁架钢筋双向叠合板的抗弯性能静载对比试验.分别从破坏形态、荷载-挠度曲线、荷载-钢筋应变曲线、荷载-滑移曲线、裂缝分布规律对试件的承载能力、受弯性能及双向受力性能等方面进行了系统分析.研究结果表明:钢纤维增强钢纤维再生混凝土叠合板与普通混凝土叠合板及普通现浇混凝土板的弯曲破坏过程相似,均经历了弹塑性阶段、塑性阶段和破坏阶段,裂缝、挠度发展均较充分,且未有突然断裂或沿叠合面出现水平裂缝等破坏现象;同时,不同的预制底板构造形式对钢纤维增强再生混凝土叠合楼板的受弯性能有较大影响,在用塑性屈服线理论计算极限承载力时,应考虑不同预制底板形式对塑性屈服线位置的影响.