凝灰岩石粉对水工泵送混凝土性能的影响

Effect of Stone Powder Content in Tuff Manufactured Sand onProperties of Hydraulic Pumped Concrete

为了确定凝灰岩机制砂中合适的石粉含量,依托厦门抽水蓄能电站,通过配制三种不同石粉含量的机制砂及其混凝土,系统研究了凝灰岩机制砂石粉对水工泵送混凝土流变性能、力学性能、早期抗裂及干燥收缩性能的影响规律。结果表明:当凝灰岩机制砂中石粉含量在8%~18%内变化时,随着石粉含量的增加,水工泵送混凝土单位用水量增加、屈服应力和塑性黏度增大、混凝土干缩变大、早期抗裂性明显变差,抗压强度和劈拉强度的变化幅度相对较小,但石粉含量仅8%时混凝土保水性和黏聚性较差;将凝灰岩机制砂石粉含量控制在13%时,水工泵送混凝土综合性能较好。研究成果可为控制凝灰岩机制砂石粉含量、优化水工泵送混凝土性能提供技术支撑。

To determine the appropriate stone powder content in tuff manufactured sand,we prepared concrete specimens mixed with tuff manufactured sand which contains three levels of stone powder content at Xiamen pumped storage power station,and investigated the effects of stone powder content on the rheological properties,mechanical properties,early cracking resistance,and drying shrinkage of hydraulic pumped concrete.Results showed that an increase in tuff stone powder content from 8%to 18%caused an increase in unit water consumption,yield stress,and plastic viscosity of hydraulic pump concrete,as well as a decrease in early-age cracking resistance and an increased dry shrinkage,while the compressive strength and splitting tensile strength were only slightly affected.When the content of tuff stone powder was reduced to 8%,the hydraulic pumped concrete exhibited inferior cohesion and water retention.The optimal tuff stone powder content was found to be around 13%to improve the overall properties of the hydraulic pumped concrete.