摘要
针对深隧工程高性能混凝土服役环境下耐久性提升需求,研究了复合掺合料对预制混凝土坍落度、力学性能和抗氯离子渗透性能的影响规律以及纤维对预制混凝土蒸养强度和早期强度的影响规律。试验结果表明,与普通掺合料相比,相同掺量下采用含硅灰的复合掺合料,C60预制混凝土的早期强度提高约5 MPa,电通量和抗氯离子渗透系数明显下降50%;在30%~45%复合掺合料掺量范围内,复合掺合料中掺加纤维后混凝土的蒸养强度下降19.5%~38.6%,1 d抗压强度下降45.6%~49.7%。深隧工程预制混凝土复合掺合料应采用不加纤维的矿粉、粉煤灰和硅灰三掺复合体系,且其最佳比例分别为50%、30%、20%。
In view of the need to improve the durability of HPC in service condition of deep tunnel engineering,the influence of composite admixtures on the slump,mechanical properties and chloride ion penetration resistance of precast concrete and the influence of fiber on steam curing strength and early strength of precast concrete are studied.The test results show that compared with ordinary admixtures,the early strength of C60 precast concrete is increased by about 5 MPa,and the electric flux and chloride ion permeability resistance coefficient are significantly reduced by 50%.In the range of 30%~45%,the steam curing strength and 1 d compressive strength of concrete decreased by 19.5%~38.6%and 45.6%~49.7%respectively.To sum up,the composite admixture of precast concrete for deep tunnel engineering shall adopt the three admixture composite system of mineral powder,fly ash and silica fume without fiber,and the optimal proportion is 50%,30%,20%,respectively.
作者
孙丹丹
於林锋
SUN Dandan;YU Linfeng(Shanghai Research Institute of Building Science Co.Ltd.,Shanghai 200032,China)
出处
《新型建筑材料》
2021年第11期125-128,共4页
New Building Materials
基金
上海市建委科研项目(住建管2019-001-001)。
关键词
深隧工程
预制混凝土
复合掺合料
deep tunnel engineering
precast concrete
compound admixtures
