聚丙烯酸钙预处理辉绿岩骨料透水混凝土性能研究

Study on properties of pervious diabase aggregate concrete pretreated with calcium polyacrylate

采用不同浓度的聚丙烯酸钙溶液对辉绿岩骨料进行预处理,研究骨料预处理对成型透水混凝土力学性能与透水性能的影响。最优骨料改性方案为:预处理溶液中丙烯酸钙浓度为10%,丙烯酸丁酯、过硫酸钾和三乙醇胺掺量分别为丙烯酸钙质量的15%、2.5%、2.5%。透水混凝土的28 d抗压强度为34.8 MPa,较空白组提高了21.2%;7 d抗压强度较空白组降低了1.8%;透水系数较空白组减小了4.1%。微观分析表明,聚丙烯酸钙参与了水泥水化产物的二次水化进程,预处理提高了骨料-水泥界面过渡区的粘结强度。聚丙烯酸钙在骨料表面与水泥的聚合作用填充了骨料表面的水泥孔隙,使后期胶结层水泥石结构致密,减少透水混凝土破坏薄弱因素,形成了形态不规则的胶凝结构,加速了骨料和水泥界面过渡区后期强度的提高,使得改性骨料透水混凝土后期强度提高。

The influence of aggregate pretreatment on mechanical strength and water permeability of formed pervious concrete was studied by preparing diabase aggregate particles with different concentrations of calcium polyacrylate solution.The optimal aggregate modification scheme was that the concentration of calcium acrylate was 10%,and the dosage of butyl acrylate,potassium persulfate and triethanolamine were 15%,2.5%and 2.5%,respectively.The 28 d compressive strength of the sample pervious concrete was 34.8 MPa,which was 21.2%higher than that of the blank group.The 7 d compressive strength decreased by 1.8%,and the water permeability coefficient decreased by 4.1%compared with the blank group.Micro analysis shows that calcium polyacrylate participates in the secondary hydration process of cement hydration products,and pretreatment improves the bond strength of the diabase-cement interface transition zone.The polymerization of calcium polyacrylate and cement on the aggregate surface fills the cement pores on the aggregate surface,makes the cement stone structure of the later cementation layer dense,reduces the weak factors of the damage of permeable concrete,forms an irregular cementitious structure,accelerates the improvement of the later strength of the transition zone between aggregate and cement,and improves the later strength of the modified pervious aggregate concrete.