不同机制砂取代率下混凝土性能研究

Research on concrete performance under different replacement ratios of manufactured-sand

为解决工程建设中天然砂资源日益短缺的难题,研究了相同配合比下,不同机制砂取代率对混凝土的力学特征、静压弹性模量、抗氯离子渗透等性能的影响,并对比分析了最佳机制砂取代率下混凝土和天然砂混凝土的抗冻性、收缩性及孔隙结构。结果表明:随着机制砂取代率的增大,试样的坍落度、氯离子渗透系数呈降低趋势,抗压强度、静压弹性模量呈先上升后降低趋势,并在取代率为40%左右时达到较佳状态;与天然砂混凝土相比,机制砂取代率为40%的混凝土其抗冻性、收缩性能均好于天然砂混凝土,且其内部孔径向着小孔径方向移动,平均孔径及孔隙率均降低,混凝土密实度得以提高。

In order to solve the shortage of natural sand in engineering construction,the influence of different replacement ratios of manufactured- sand on mechanical characteristics,static modulus of elasticity and resistance to chloride ion permeation of concrete were explored. Moreover the frost resistance,shrinkage and pore structure of optimal manufactured- sand concrete and normal concrete were compared. The test results show that with the increasing of manufactured- sand replacement ratio,the slump,chloride ion permeation coefficient shows a decreasing trend,and the compressive strength,static modulus of elasticity increase first and then decrease; the best replacement ratio is 40%. Compared with the natural- sand concrete,the frost resistance and shrinkage of concrete with a manufactured- sand replacement ratio of 40% is better,and the internal- aperture moves toward the small aperture,both the average pore diameter and porosity decrease,and the dense degree of concrete is improved.