砂轻混凝土抗压强度指标换算关系试验研究

Experimental Study on the Conversion Relationships of Compressive Strength Indexes of Sand-lightweight Concrete

为了研究砂轻混凝土的受压性能及强度指标换算关系,以页岩陶粒为粗骨料,天然砂取代率为设计参数,制作5组标准立方体和5组标准棱柱体砂轻混凝土试块,进行抗压强度试验。考察了砂轻混凝土受压破坏过程与破坏形态;基于试验数据,探讨了天然砂取代率对砂轻混凝土抗压强度的影响规律,给出了轴心抗压强度与立方体抗压强度比值与天然砂取代率之间的关系式。研究结果表明:随天然砂取代率的增加,砂轻混凝土立方体受压破坏脆性逐渐降低,韧性逐渐显著,轴心受压破坏形态由纵向劈裂破坏转为斜截面剪切破坏;随着天然砂取代率的增加,砂轻混凝土抗压强度逐渐增加;通过回归分析,提出的无量纲化后立方体抗压强度、轴心抗压强度及两者之间的比值与天然砂取代率的关系式简单实用,精度较高。

To study compression performance and the conversion relationships between compression strength indexes of sand-lightweight concrete,5 groups of standard cube specimens and standard prism specimens of sand-lightweight concrete specimens were made with shale ceramsite as coarse aggregate and natural sand replacement rate as design parameters,and then compressive strength tests were carried out.The compression failure process and damage mode of sand-light concrete are investigated.Based on the test data,the effect of replacement rate impact on the compressive strength of sand-lightweight concrete is discussed,and the relationship between the ratio of axial compressive strength to cube compressive strength and the replacement rate of natural sand is given.The results show that the brittle failure of cube specimens reduces gradually as replacement rate of nature sand increases,and the toughness changes significantly.The failure mode of the axial compression is transformed from the longitudinal splitting failure to the oblique section shear failure.The compressive strength of sand-lightweight concrete increases gradually as replacement rate of natural sand increases.Through regression analysis,the relationships of dimensionless parameter of compressive strength,axial compressive strength and their ratio to the replacement rate of natural sand are proposed,which are more applicable and accurate.