不同细骨料混凝土力学性能及多工况耐久性能

    Different Fine Aggregate Concrete Mechanical Properties and Multi-condition Durability Performance

    • 摘要: 为了了解不同细骨料混凝土力学性能及多工况耐久性能,利用河砂、机制砂和风积沙制备混凝土进行力学性能和不同工况下耐久性能试验研究,并结合微观结构试验,探究不同细骨料对混凝土性能的影响机理。 结果表明:机制砂可提升混凝土的力学性能,风积沙则降低混凝土的力学性能,二者均降低了混凝土的工作性能;在硫酸盐冻融干湿耦合条件下,风积沙混凝土的质量损失率呈指数型增长,大幅度降低了混凝土的耐久性;机制砂增加了水泥基质强度并且强化孔隙结构使闭口孔隙占比相对增多,弱化了混凝土在硫酸盐冻融干湿耦合条件下冻胀力和结晶压力对孔隙结构的破坏作用,提升混凝土的耐久性;通过对损伤数据拟合进行寿命预测得出,机制砂提升了混凝土在不同工况条件下的耐久性,而风积沙只能提升混凝土在硫酸盐冻融工况下的耐久性。

       

      Abstract: The mechanical properties and durability of concrete prepared by river sand, machine-made sand and aeolian sand under different working conditions were studied. Combined with the microstructure test, the influence mechanism of different fine aggregates on the performance of concrete was explored. Results show that manufactured sand can improve the mechanical properties of concrete, while aeolian sand reduces the mechanical properties of concrete. Both of them reduce the working performance of concrete. Under the condition of sulfate freeze-thaw dry-wet coupling, the mass loss rate of aeolian sand concrete increases exponentially, which significantly reduces the durability of concrete. The manufactured sand increases the strength of the cement matrix and strengthens the pore structure to increase the proportion of closed pores, which weakens the damage of frost heaving force and crystallization pressure on the pore structure of concrete under the condition of sulfate freeze-thaw and dry-wet coupling, and improves the durability of concrete. Through the life prediction of damage data fitting, it is concluded that manufactured sand improves the durability of concrete under different working conditions, while aeolian sand can only improve the durability of concrete under sulfate freeze-thaw conditions.

       

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