超缓凝混凝土的配制及工程应用

Preparation and engineering application of ultra-retarded concrete

结合工程实际,使用Ⅰ级风选粉煤灰、S75级磨细矿粉、高性能减水剂以及超缓凝外加剂,在低胶凝材料用量情况下配制大流动性、高保坍C30水下超缓凝泵送混凝土。经过原材料选择、工作性能评价、抗压强度测试等方面的研究,确定了C30水下超缓凝泵送混凝土配合比。测试结果表明,混凝土拌合物性能与凝结时间能满足钻孔咬合桩施工工艺要求,硬化混凝土强度满足结构实体技术指标,具备很好的经济价值和推广意义。

Combining with the actual engineering practice,the C30 underwater retarding pumping concrete with large fluidity and high-slump retention performance was prepared by using the first-class air separation fly ash,S75 graded fine powder,highperformance water reducing agent and ultra-retarded concrete admixture,under the condition of low cementitious material dosage.Based on the selection of raw materials,performance evaluation,and compressive strength tests,the C30 underwater ultra-retarded pumping concrete mix ratio was determined. The results show that the performance and setting time of the concrete mixture can meet the construction requirements of bored secant pile,and the strength of the hardened concrete meets the technical indicators of the structural entity. Ultra-retarded concrete technology has good economic value and promotion significance.