超高性能混凝土中石英砂级配设计及最佳掺量研究

Study on Gradation Design and Optimal Mixing Amount of Quartz Sand in Ultra-high Performance Concrete

在胶凝体系相对稳定的基础上,对比分析了经典堆积密度模型(Andreasen模型、Dinger-Funk模型、Fuller曲线)和逐层堆积试验方法对石英砂体系级配最紧密堆积设计的适用性;选取最佳密实配比的石英砂体系,研究其掺量对UHPC工作力学性能的影响。研究结果表明:石英砂体系堆积密度提升效果排序为:逐层堆积试验方法>Andreasen模型>Dinger-Funk模型>Fuller曲线,石英砂体系密实程度最佳达到1802 kg/m^(3);砂胶比在1.0~1.3时,UHPC的综合性能最佳;当石英砂体系堆积密度大于1700 kg/m^(3)时,力学性能的提升效果不再显著,可根据性能需求,选择逐层堆积试验方法或Andreasen模型理论计算方法进行石英砂体系的级配设计。

On the basis of relatively stable cementitious system,the applicability of classical bulk density model(Andreasen model,Dinger-Funk model,Fuller curve)and layer by layer stacking test method to the most compact packing design of quartz sand system gradation was compared and analyzed.The best dense ratio of quartz sand system was selected to study the influence of its content on the mechanical properties of UHPC.The results show that the effect order of packing density improvement of quartz sand system is as follows:layer by layer packing test method>Andreasen model>Dinger-Funk model>Fuller curve.The optimum density of quartz sand system is reaching 1802 kg/m^(3);when the sand binder ratio is between 1.0 and 1.3,the comprehensive performance of UHPC reaches best.What shows differences from the most results is that the packing density of quartz sand is not proportional to the mechanical properties of UHPC when the cementitious system is fixed.When the bulk density of quartz sand system is greater than 1700 kg/m^(3),the improvement effect of mechanical properties is no longer significant.According to the performance requirements,the layer by layer stacking test method or Andreasen model theoretical calculation method can be selected for the grading design of quartz sand system.