砂轻页岩集料混凝土拉压比及其变形性能试验

Experimental Study on Tension-compression Ratio and Deformation Performance for Lightweight Concrete with Shale Aggregate Replaced Partially by Nature Sand

为研究砂轻页岩集料混凝土的基本力学性能,制作了10组立方体标准试块和10组棱柱体标准试块,测试了试块立方体抗压强度、劈裂抗拉强度、弹性模量和泊松比,考察了试块破坏过程与破坏形态,分析了天然砂取代率对砂轻页岩集料混凝土力学性能的影响。试验表明:砂轻页岩集料混凝土的破坏形态与普通混凝土不同;随着天然砂取代率的增加,砂轻页岩集料混凝土的立方体抗压强度、轴心抗压强度、劈裂抗拉强度、拉压比呈总体增加趋势;通过回归分析,提出的砂轻页岩集料混凝土劈裂抗拉强度与天然砂取代率之间的关系式简单实用,精度较高;随天然砂取代率的增加,砂轻页岩集料混凝土的弹性模量逐渐增加,而泊松比则相反;通过引入取代率影响参数,建立了砂轻页岩集料混凝土拉压比-泊松比曲线方程,计算曲线与实测曲线吻合良好。

In order to study the essential mechanical properties of lightweight concrete with shale aggregate replaced partially by nature sand(LCSARPNS), the mechanical property experiments were conducted on ten groups of cubic standard specimens and ten prismatic standard specimens. Cube compressive strength, axial compressive strength, splitting tensile strength, elastic modulus and Poisson’s ratio were measured, the failure processes and failure modes were observed, and influences of replacement rates of nature sand on essential mechanical properties of LCSARPNS were analyzed. Results show that the failure modes of LCSARPNS are different from ordinary concrete. Generally the associated mechanical indexes of LCSARPNS show an increasing trend as replacement rates of natural sand increase, including the cube compressive strength, axial compressive strength, splitting tensile strength, tension-compression ratio. In terms of LCSARPNS, a precise and applicable relationship for splitting tensile strength at various replacement rates of natural sand was established by regression analysis. The elastic modulus of LCSARPNS increases gradually with the increase of replacement rate of natural sand, while the reverse is true for the Poisson’s ratio. Based on the introduced parameter in association with the replacement rate of natural sand, the curve equation between tension-compression ratio and Poisson’s ratio for LCSARPNS was established, and the calculated curves for tension-compression ratio correlate well to the experimentally measured ones.