C40低温升抗裂大体积混凝土设计制备及其性能研究

Study on the preparation and properties of C40 mass concrete of low temperature rise and anti-cracking

针对普通C40大体积混凝土胶凝材料用量高、绝热温升大和易收缩开裂等问题,提出采用高掺粉煤灰+矿粉复合矿物掺合料,复配超分散减缩外加剂+水化温升抑制剂等措施,制备出的C40低温升抗裂大体积混凝土7 d绝热温升仅为31.87℃,60 d自收缩和干燥收缩为227×10^(-6)、241×10^(-6),抗裂等级达到L-V。研究成果已成功应用于白洋长江公路大桥主塔承台和锚碇,在取消通冷却水管情况下,混凝土未产生有害温度裂缝和收缩裂缝。

Aimed at solving the problem of cementitious material consumption,the adiabatic temperature rise and larger shrinkage cracking of ordinary C40 large mass concrete,by using high content of fly ash and slag as composite mineral admixtures and mixture of ultra dispersed admixture and temperature rise inhibitor,C40 mass concrete with 7 d adiabatic temperature rise of only 31.87 ℃,autogenous shrinkage of 227×10^-6 and drying shrinkage of 241×10^-6,and anti-cracking grade of L-V is prepared.The result has been successfully applied to in cushion cap and anchorage spread foundation of Bai Yang Yangtze River Highway Bridge.In case of cancellation of cooling water pipes,no harmful temperature cracks and shrinkage cracks are found.