石粉含量对C45凝灰岩机制砂混凝土性能的影响

Effect of Stone Powder Content on Properties of C45 Tuff Manufactured Sand Concrete

采用坍落度、振动凯氏球体试验,以及抗压强度、静压弹性模量、劈裂抗拉、混凝土表观电阻率试验,分析了石粉含量对C45凝灰岩机制砂混凝土(MSC)工作性、力学性能、抗氯离子渗透性能的影响;通过二次项式拟合分析,结合MSC与天然砂混凝土(NSC)的对比研究,给出了C45凝灰岩MSC的推荐石粉含量。结果表明:随着石粉含量的提高,C45凝灰岩MSC的坍落度、振动凯氏系数、抗压强度、静压弹性模量、劈裂抗拉强度、抗氯离子渗透性能均先增大后减小,存在最佳石粉含量;当对混凝土的要求为坍落度>100 mm、静压弹性模量>44 GPa时,C45凝灰岩MSC的推荐石粉含量为2%~5%(质量分数,下同);当对混凝土的要求为坍落度<100 mm、静压弹性模量<44 GPa时,推荐石粉含量为可放宽为5%~8%;合理控制机制砂石粉含量可以使C45凝灰岩MSC的综合性能优于C45 NSC。

The effect of stone powder content on the workability,mechanical properties and chloride ion penetration resistance of C45 tuff manufactured sand concrete(MSC)were assessed by applying the slump test,Vkelly test,compressive strength,elastic modulus,splitting tensile strength and surface resistivity tests.In accordance with the fitting analysis of quadratic formula and the comparative study of MSC and natural sand concrete(NSC),the suggested stone powder content of C45 tuff MSC was established.The results indicate that the slump,Vkelly index compressive strength,elastic modulus,splitting tensile strength and chloride ion penetration resistance of C45 tuff MSC increase first and then start to decrease with the increase of stone powder content in a certain range.In engineering applications,if the specific required slump is greater than 100 mm and elastic modulus is higher than 44 GPa,the suggested stone powder content of C45 tuff MSC is between 2%(mass fraction,the same below)and 5%.Otherwise,the suggested stone powder content between 5%and 8%is accepted.Reasonable control of the stone powder content of manufactured sand can yield a better engineering performance of C45 tuff MSC compared with C45 NSC.