矿渣细度对高性能混凝土性能的影响

Influence of slag fineness in high performance concrete

试验选用细度为420、530、610、720 m2/kg的矿渣等量取代水泥20%、40%、60%去配制混凝土,研究其对混凝土工作性,抗压强度和耐久性能的影响。试验结果表明,混凝土的坍落度和抗氯离子渗透性不仅受矿渣掺量的影响,而且还受矿渣细度的影响,矿渣粉的掺量对混凝土抗冻性能的改善相对于细度显著;当矿渣粉的细度小于530m2/kg,混凝土的7 d抗压强度随着矿渣掺量的提高而降低,28、56 d抗压强度随着矿渣掺量的提高而增加,当矿渣粉的细度大于530 m2/kg,矿渣粉的掺量40%,混凝土7 d抗压强度达到最大,28、56d抗压强度随着矿渣掺量的提高而增加。利用功效函数法优化出,当矿渣的细度为720 m2/kg掺量40%时,混凝土综合性能最优。

From the viewpoint of low carbon green concrete, this research focuses on investigating the concrete containing slag with different fineness and dosage.For this purpose, the workability, compressive strength at different ages, chloride ion penetration, and frost resistance were investigated, with slag surface area 420,530,610,720 m2/kg, and replacement percentage 0,20%, 40%, 60%, respectively.It was found that the fineness and dosage of slag improve the concrete workability and chloride-penetration resistance property, and the influ- ence of dosage on frost resistance is higher than fineness.The 7 d compressive strength decreased with slag replacement increasing when the fineness of slag is lower than 530 m2/kg, and 28 d and 56 d compressive strength increased;for the fineness higher than 530 m2/kg, the 7 d compressive strength is higher than that of control concrete, when the slag replacement was 40%, the concrete reached the highest value, and the 28 d and 56 d compressive strength increased with slag incorporation.The concrete expressed better comprehensive properties when the fineness is 720 m2/kg with slag replacement 40~/0 ,based on the efficacy coefficient method.