再生混凝土单排孔砌块力学性能研究

Experimental study on mechanical properties of recycled concrete single-row blocks

考虑再生粗骨料和细骨料的取代率、单位用水量、水灰比四个因素,设计正交试验对再生混凝土单排孔砌块的抗压和抗折强度进行试验研究,根据试验结果得到各因素对砌块力学性能的影响程度及规律,并得到较优配合比,即单位用水量150 kg/m3,水灰比为0.4,再生粗、细骨料取代率均为40%。将再生混凝土视为退化的普通混凝土,从实际水灰比和再生集料压碎指标方面分析了再生混凝土砌块强度变化的内在机理。定义了再生混凝土砌块的再生集料影响系数D,得出D与再生混凝土砌块的强度存在显著的线性相关关系。在较优配合比组合的基础上研究了砂率对再生混凝土砌块抗压强度的影响,配制出了强度等级为MU5.0的再生混凝土单排孔承重砌块。

Considering the effects of four factors, including recycled coarse aggregate replacement ratio, recycled fine aggregate replacement ratio, water consumption and water-cement ratio, an or-thogonal test was conducted to study the compressive and flexural strength of recycled concrete sin-gle-row blocks. According to the experimental results, the influences of four factors on mechanical properties of recycled concrete blocks were summarized, and the optimal mixture ratio was found （water consumption is 150 kg / m3 , water-cement ratio was 0. 4, recycled coarse and fine eggregates ratios were 40% ）. Recycled concrete was regarded as the degradation of normal concrete. The actu-al water-cement ratio and crushing index of recycled aggregate were proposed to analyze the internal mechanism of strength variation of recycled concrete blocks. The impact factor D of recycled aggre-gate for recycled concrete single-row blocks was defined, and the relationship between impact factor D and the strength of blocks was also analyzed. Based on the former optimal mixture ratio, the influ-ence of sand ratio on the compressive strength of recycled concrete single-row blocks was investiga-ted; thereby a type of load-bearing recycled concrete single-row block with strength degree of MU 5. 0 was developed.