细矿粉混凝土的制备及耐久性能研究

Study on preparation and durability of fine mineral powder concrete

选择以S95级细矿粉为外掺料,制备了不同细矿粉掺杂量(0%,5%,10%,15%,20%(质量分数))的混凝土,通过XRD、SEM、力学性能、抗冻性能、电通量测试等分析了细矿粉掺杂量对混凝土性能的影响。结果表明,掺入适量的细矿粉后加速了水化反应的进行,促进了水泥熟料的消耗,使混凝土的密实度提高,裂纹和孔隙的数量减少。随着细矿粉掺杂量的增加,混凝土的抗压强度和抗弯强度均先增大后降低,当细矿粉的掺杂量为15%时,混凝土的抗压强度和抗弯强度达到最大值,分别为40.1和5.79 MPa。混凝土受压的峰值应力随细矿粉掺杂量的增加而先增大后降低,掺杂15%细矿粉的混凝土的峰值压力最大。适量细矿粉的添加改善了混凝土的抗冻性能,在冻融循环次数达到100次,当细矿粉的掺杂量为15%时,混凝土的相对动弹性模量最大为82.48%,质量损失率最低为-0.282%,其抗冻性能最佳。混凝土的电通量随着细矿粉掺杂量的增加先降低后轻微增大,掺杂15%细矿粉的混凝土的电通量最低为1914 C,其抗氯离子渗透性能最优。综合分析强度和耐久性可知,细矿粉的最佳掺杂量为15%。

With S95 grade fine mineral powder as the additive,the concrete with different doping amount of fine mineral powder(0,5wt%,10wt%,15wt%,20wt%)was prepared.Through XRD,SEM,mechanical properties,frost resistance and electrical flux test,the influence of fine mineral powder doping on concrete performance was analyzed.The results showed that the addition of proper amount of fine mineral powder accelerated the hydration reaction,promoted the consumption of cement clinker,improved the compactness of concrete,and reduced the number of cracks and pores.With the increased of fine mineral powder,the compressive strength and flexural strength of concrete increased first and then decreased,when the content of fine mineral powder was 15wt%,the compressive strength and flexural strength of concrete reached the maximum,which were 40.1 and 5.79 MPa respectively.The peak compressive stress of concrete increased first and then decreased with the increase of fine mineral powder doping,and the peak compressive stress of concrete doped with 15wt%fine mineral powder was the largest.The frost resistance of concrete was improved by adding appropriate amount of fine mineral powder.When the number of freeze-thaw cycles reached 100,when the amount of fine mineral powder was 15wt%,the maximum relative dynamic modulus of elasticity of concrete was 82.48%,and the minimum mass loss rate was-0.282%,its frost resistance was the best.The electrical flux of concrete decreased first and then increased slightly with the increase of fine mineral powder doping.The lowest electrical flux of concrete doped with 15wt%fine mineral powder was 1914C,and its chloride ion penetration resistance was the best.According to the comprehensive analysis of strength and durability,the best doping amount of fine mineral powder is 15wt%.