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机制砂级配调整及混凝土泵送施工质量控制
作者：郑振尧，李冬，姜立孟
（威海建设集团股份有限公司，山东 威海 264200）
摘要：为提高机制砂混凝土的泵送性能，拓展机制砂在混凝土中的利用率，随机调研了云南地区21个机制砂加工厂，取样筛分得到级配曲线，并与相关国家标准、行业标准及现行地方标准对机制砂级配区的规定进行对比。结果表明：机制砂普遍存在粗颗粒和粉体颗粒多，中间颗粒少的现状；通过控制4.75、2.36 mm筛孔通过率同时减少0.15 mm筛孔以下的粉体含量，可以得到满足不同级配区间上下限要求的机制砂；经过级配改良为Ⅱ区砂的预拌机制砂混凝土的坍落度和扩展度均优于未改良的机制砂混凝土；通过加强棱角包裹性、机制砂棱角整型以及调整机制砂级配的方法，可以改善机制砂混凝土的泵送堵管现象。
关键词：机制砂；级配；混凝土；泵送；施工
中图分类号：TU528.041 文献标识码：A 文章编号：1001-702X（2020）11-0126-04
Grading adjustment of crushed sand and quality control on concrete pumping construction
ZHENG Zhenyao，LI Dong，JIANG Limeng
（Weihai Construction Group Co. Ltd.，Weihai 264200，China）
Abstract：In order to improve the pumping performance of crushed sand concrete and enlarge the using range of crushed sand in concrete，21 crushed sand plants in Yunnan Province have been investigated by random. Samples are obtained to get the grading curves. Comparing the real produced crushed sand to the related national standards，industrial standards and prevailing local standards，the result shows that the content of coarse particles and powder of the crushed sand obtained are abundant. The particles in the middle size are short. By controling the passing rate of 4.75 mm and 2.36 mm particles and reducing the amount of particles whose size is below 0.15 mm，the crushed sand can satisfy the rules of standards. The test result shows that the slump and divergence of concrete with adjustment crushed sand is better than the one without adjustment. By means of enhancing the attached slurry，particle abrasion and grading adjustment，it can improve the pumping pipe blocking phenomenon of crushed sand concrete.
Key words：crushed sand，grading，concrete，pumping，construction