含白云石粗骨料超高性能混凝土的性能试验研究

Properties of Ultra-high Performance Concrete Containing Coarse Dolomite Aggregate

为了降低超高性能混凝土(UHPC)中水泥等胶凝材料的用量,掺入白云石粗骨料(CDA),制备了含CDA的UHPC,并探讨了粗骨料含量和钢纤维体积掺量对UHPC抗压强度、弯曲强度、弹性模量、单轴拉伸性能以及耐磨性能的影响。结果表明:随着CDA含量的增加,UHPC弹性模量的显著提升,而抗压强度和弯曲强度则先上升后下降;钢纤维体积掺量的增加,增大了含CDA的UHPC的抗压强度、初裂强度、峰值强度和断裂耗能,降低了试件历经磨损后的质量损失和磨损深度,优化了其单轴拉伸性能和耐磨性能;当CDA含量为200 kg/m^3、钢纤维体积掺量为1.5%时,制备的UHPC各项性能综合最佳。研究成果可供超高性能混凝土研究人员参考。

In order to reduce the amount of cementitious materials in ultra-high performance concrete(UHPC),we prepared UHPC specimens containing coarse dolomite aggregate(CDA)and investigated the effects of CDA content and steel fiber volume on compressive strength,flexural strength,elastic modulus,uniaxial tensile property and abrasion resistance of UHPC.Results revealed that with the increase of CDA dosage,the elastic modulus improved significantly,the compressive and flexural strength of UHPC increased firstly but then decreased.On the one hand,as the volume of steel fiber increased,the uniaxial tensile property of UHPC were enhanced,wherein improving the compressive strength,first cracking strength,post cracking strength and energy absorption capacity of UHPC.On the other hand,the mass loss and depth of abrasion reduced with the increase of steel fiber content which represents the optimization of abrasion resistance of UHPC.When the dosage of CDA was 200 kg/m^3 and the volume of steel fiber was 1.5%,the comprehensive performances of UHPC reached the optimum.