寒冷地区负温泵送混凝土与高强混凝土冬季施工技术研究

A TECHNOLOGICAL RESEARCH ON CONCRETE STRENGTH DURING WINTER CONSTRUCTION OF THE NEGATIVE TEMPERATURE PUMPED CONCRETE AND HIGH STRENGTH CONCRETE IN COLD REGION

在实验室配制的掺4 %高效泵送防冻剂和磨细粉煤灰的C30、C40强度等级的混凝土 ,其各龄期强度及坍落度损失等均能满足冬施泵送混凝土施工要求 ,且自然变负温养护对负温混凝土强度发展十分有利。用掺3 %的高效防冻剂和磨细粉煤灰配制强度等级为C50的负温高强混凝土 ,其各龄期强度及抗冻性能均能满足设计要求。同龄期变负温养护的混凝土试件强度较明显高于恒负温养护的混凝土强度。C40负温泵送混凝土及C50负温高强混凝土在实际工程中强度增长率与实验室条件下试验结果基本相近。

The laboratory practice has shown that mixing with 4% highly-effective pumped-concrete freeze-proof agent and finely-ground coal-ash admixture,the C30 and C40 high strength concrete have been produced.Furthermore,their concrete strength and slump fully fulfill the requirements of pumped concrete in winter construction.Besides,it has shown that the varying negative temperature curing methods have been found helpful for promotion of negative temperature concrete strength.While mixing with 3% highly-effective freeze-proof agent and finely-ground coal-ash admixture,the C50 negative temperature high strength concrete has been made;and fulfilled the design's requirements of freeze-proof concrete strength of various curing period.Besides,the strength of varying negative temperature cured concrete is higher than the strength of constant negative temperature cured concrete.In conclusion,it has been noted that the general field practice of C40 negative temperature pumped concrete and C50 negative temperature high strength concrete coincides basically with those of the laboratories.