长时间运输高性能泵送混凝土配比优化措施研究  

Experimental study of mixing proportion optimization of high performance pumping concrete under long-time transportation

作　　者：程伟峰[1,2] 何金荣[3] 林星平[1,2] 

机构地区：[1]中国水电顾问集团昆明勘测设计研究院,云南昆明650033 [2]锦屏水电工程东端中心试验室,四川西昌615615 [3]二滩水电开发有限责任公司,四川成都610021

出　　处：《武汉大学学报（工学版）》2014年第1期59-65,共7页Engineering Journal of Wuhan University

基　　金：二滩水电开发有限责任公司锦屏建设管理局专题研究项目(JPQ(2010)46号;JPQ(2010)86号)

摘　　要：锦屏二级水电站东端工程大型地下洞室群二次衬砌用泵送混凝土主要存在单位用水量及胶凝材用量偏高、砂率偏大、未掺粉煤灰及引气剂、人工砂石粉含量超标且波动较大等诸多问题,致使新拌混凝土和易性差,存在泌水、离析及坍落度经时损失较快等现象,不能满足现场长时间运输及泵送施工要求;硬化混凝土超强、抗渗及抗冻性差.为此,采用4种粉煤灰优选、萘系及聚羧酸系共7种减水剂比选、掺入引气剂、粗骨料比例优化组合比选、优选砂率、人工砂不同石粉含量对混凝土性能影响试验、坍落度损失控制研究等系列措施进行了配合比优化试验研究,结果降低了混凝土单位用水量及胶凝材用量,改善了混凝土和易性,强度更趋合理,耐久性能提高,坍落度损失满足长时间运输要求,并取得了较大的经济效益.配合比投入使用后,采取了系列质量控制措施,确保优化成果应用于工程实际.There are some problems about pumping concrete for second lining of large-scale underground tunnel group of Jinping H hydropower station, such as high water and cementing materials usage per unit volume of concrete, high S/A ratio, no fly ash replacement and air entrained agent in concrete, and stone dust content of the artificial sand out of limit with fluctuating product quality, etc. , which result in poor fresh concrete workability with segregation, bleeding and high slump loss, and lead to overstrength problem and worse antiseepage ability and frost resistance of harden concrete. Therefore, in this paper, by means of preferred test for the fly ash and water reducing agent mixed with air-entraining agent, optimization of the sand ratio and the combination of different coarse aggregates, effect study of high powder-content artificial sand on pumping concrete performance, and study of the ability of slump maintenance, mixing proportion of concrete were optimized. These measures efficiently lowere the unit water and cement , improved the workability, durability and the economy and rationalize the strength, and controll the slump loss meeting with the long-time transport requirement. According to the practical application situation of concrete with recommended mixing proportion, a series of effective quality control measures are taken to ensure the application of optimal results to the project.

关 键 词：锦屏二级水电工程 长时间运输 高性能泵送混凝土 配比优化 质量控制 

分 类 号：TU528.041[建筑科学—建筑技术科学]