压型钢板再生混合混凝土组合楼板受力性能试验研究

通过对15个压型钢板再生混合混凝土组合楼板试件（9个无栓钉试件，6个有栓钉试件）的受力性能试验，研究废旧混凝土块体取代率、剪跨、板厚、栓钉布置方式等参数对试件纵向受剪性能和受弯性能的影响；基于新、旧混凝土的组合强度，确定了试件纵向受剪承载力的计算系数，考察了相关公式预测试件受弯承载力的有效性。研究表明：废旧混凝土块体取代率为21%~36%时，无栓钉压型钢板再生混合混凝土组合楼板的纵向受剪承载力相比全现浇组合楼板偏差-13.1%~11.7%，但未呈现出随取代率的单调变化规律；废旧混凝土块体取代率为11%~31%时，有栓钉压型钢板再生混合混凝土组合楼板的初始刚度与全现浇组合楼板基本相同，同时前者具有不低于后者的受弯承载能力；参照CECS 273-2010《组合楼板设计与施工规范》中相关公式，预测了压型钢板再生混合混凝土组合楼板的受弯承载力，其结果具有不低于全现浇组合楼板的设计安全性。

Mechanical property of composite slabs with profiled steelsheet casted using demolished concrete blocksand fresh concrete

Mechanical properties of fifteen composite slabs with profiled steel sheet casted using demolished concrete blocks (DCBs) and fresh concrete (FC) have been experimentally studied, including nine slabs without studs and six slabs with studs, and the influences of some parameters (i.e., replacement ratio of DCBs, shear span, thickness of slab, and arrangement of studs) on the specimens’ longitudinal shear behavior and flexural behavior have been investigated. Based on the combined strength of fresh concrete and demolished concrete, the values of two coefficients used in the calculation of the specimen’s longitudinal shear capacity have been determined, and the validity of current formulas in predicting the specimen’s flexural capacity has been checked. It is found that: when the replacement ratio of DCBs ranges from 21% to 36%, the difference between the longitudinal shear capacity of the specimen without studs casted using DCBs and FC and that of the specimen without studs casted using FC alone is within a range of -13.1%~11.7%, but this difference does not change monotonically with the increase of the replacement ratio of DCBs; when the replacement ratio of DCBs ranges from 11% to 31%, the initial stiffness of the specimen with studs casted using DCBs and FC is almost the same as that of the specimen with studs casted using FC alone, and the flexural capacity of the former is not lower than that of the latter; and the safety margin of the predicted flexural capacity using CECS 273—2010 for the specimen with studs casted using DCBs and FC is not less than that for the specimen with studs casted using FC alone.