主塔墩承台C35大体积混凝土配合比设计与性能研究

结合赤壁长江大桥4#主塔墩承台大体积混凝土的温控防裂,测试了大掺量粉煤灰和矿粉复合掺合料与缓凝聚羧酸减水剂对胶凝材料水化热的影响,对比研究了3组大掺量矿物掺合料C35混凝土的工作性、力学性能、绝热温升及耐久性能。结果表明,缓凝型减水剂与大掺量矿物掺合料的复合掺入对胶凝材料水化热的控制具有协同作用;采用32.5%粉煤灰与12.5%~22.5%矿粉复合掺合料与缓凝型聚羧酸减水剂配制的承台C35混凝土具有良好的工作性、较低的水化热温升、较高的后期强度发展和高抗氯离子渗透性等特性。

Mix proportion design and performance study of C35 mass concrete for main tower pier cap

Combined with the thermal cracks control of the mass concrete applied in 4#main tower pier cap of Chibi Yangtze River bridge,the effect of high-volume fly ash and blast furnace slag as compound mineral admixture incorporating retarding polycarboxylate superplasticizer on the hydration heat of cementitious materials were evaluated,and their influences on workability,mechanical properties,adiabatic temperature rise and durability were studied with three C35 mix proportions.The results indicate that an incorporating effect exists retarding polycarboxylate superplasticizer and high-volume mineral admixture on the hydration heat.And the C35 concretes with 32.5%fly ash,12.5%~22.5%blast furnace slag present good workability,low temperature rise caused by hydration heat,high long term strength and good chloride penetration resistance.