非连续级配再生粗骨料自密实混凝土基本力学性能试验研究

Experimental study on basic mechanical properties of self-compacting recycled concrete with discontinuous graded recycled coarse aggregate

为了研究非连续级配再生粗骨料自密实混凝土的基本力学性能,设计了C20,C30,C40三种强度等级的试件,通过试验研究了不同再生粗骨料取代率下非连续级配再生粗骨料自密实混凝土的立方体抗压强度、轴心抗压强度、弹性模量和劈裂抗拉强度。研究结果表明:随着再生粗骨料取代率的增加,混凝土立方体抗压强度下降,早期强度增长快;其破坏形式与普通混凝土的破坏形式相似;传统再生混凝土轴心抗压强度与立方体抗压强度计算模型不适用于非连续级配再生粗骨料自密实混凝土,非连续级配再生粗骨料自密实混凝土弹性模量比传统再生混凝土弹性模量要高,与普通混凝土相比略有下降。提出了非连续级配再生粗骨料自密实混凝土的轴心抗压强度与立方体抗压强度计算关系式和弹性模量、劈裂抗拉强度与立方体抗压强度的计算关系式。

Three strength grades of self-compacting recycled concrete,grading of C20,C30,C40,were designed to study the basic mechanical properties of self-compacting recycled concrete(SCRC) with discontinuous graded recycled coarse aggregate.The cubic compressive strength,axial compressive strength,elastic modulus and splitting tensile strength of SCRC with discontinuous graded recycled coarse aggregate under different replacement rates of recycled coarse aggregate were experimentally researched.The results indicate that the cubic compressive strength decreases and the early strength grows quickly with the increasing of replacement rate of recycled coarse aggregate.The failure mode of cubic specimens is similar as normal concrete.The calculation models of axial compressive strength and cubic compressive strength of traditional recycled concrete are not suitable for SCRC with discontinuous graded recycled coarse aggregate.The elastic modulus of SCRC with discontinuous graded recycled coarse aggregate is lower than that of normal concrete,but is higher than that of traditional recycled concrete.The formula of cubic compressive strength and axial compressive strength for SCRC with discontinuous graded recycled coarse aggregate was proposed as well as the formula of elastic modulus,splitting tensile strength and cubic compressive strength for SCRC with discontinuous graded recycled coarse aggregate.