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今年5月9日,正在施工中的上海自行车赛场道路基础工程,约6m~3商品混凝土出现了未硬化现象,涉及面积达15m~2左右,给工程带来了严重的影响。由于商品混凝土由某搅拌站供应,事故发生后,为了查清原因,杜绝类似事故发生,我公司会同搅拌站有关人员,对混凝土配合比、生产工艺、运输等进行了调查,并对可疑样品进行了试验分析。首先,我们榆查了配合比。根据施工单位要求,混凝土设计标号为250号,坍落度为11±1cm,骨料采用5～40mm 碎石、中粗砂,水泥为525号普通硅酸盐水泥,外掺磨细粉煤灰。每立方米混凝土材料用量分别:水泥为290kg、砂778kg、石1055kg、粉煤灰50kg、水195kg。检查结果表明,配合比设计基本正确。因此,我们又检查了称量系统。该搅拌站系采用全套国产化的混凝土搅拌楼,所有
On May 9 of this year, under the construction of the road infrastructure project of the Shanghai Cycling Stadium, about 6m~3 of commodity concrete appeared unhardened, involving an area of about 15m~2, which caused serious impact on the project. Since the commercial concrete was supplied by a mixing plant, after the accident, in order to find out the reasons and prevent similar accidents, our company investigated the concrete mix ratio, production process, transportation, etc., and related suspects. Test analysis. First, we checked the mix ratio. According to the requirements of the construction unit, the concrete design number is 250, the slump is 11±1cm, the aggregate is 5 to 40mm gravel, medium coarse sand, and the cement is No. 525 ordinary portland cement, with finely ground fly ash . The amount of concrete materials per cubic meter was 290kg for cement, 778kg for sand, 1055kg for stone, 50kg for fly ash, and 195kg for water. The inspection results show that the mix design is basically correct. Therefore, we checked the weighing system again. The mixing station uses a full set of domestic concrete mixing towers, all