三峡三期工程大坝混凝土生产质量控制

Quality Control of Dam Concrete Production for the Third Phase in the Three Gorges Project

大坝混凝土质量问题许多是在混凝土生产环节引起的.混凝土生产包括原材料准备及拌和两个方面,任何一方面降低质量要求都将导致混凝土的强度等级及其他力学指标降低,容易造成工程质量缺陷,甚至引发工程事故.然而三峡三期工程质量优良,且创造了混凝土大坝无裂缝的奇迹.从混凝土原材料质量控制和混凝土拌和生产质量控制两方面总结了三峡三期工程大坝混凝土生产质量控制的方法、措施及技术创新.在混凝土原材料质量控制方面,阐述了水泥和粉煤灰、外加剂、砂石骨料的质量控制.在混凝土拌和生产质量控制方面,论述了混凝土配合比优化设计,称量设备的定期检测,冷风机冲霜,二次砸石测温,混凝土拌和工艺,混凝土的出机口温度、坍落度、含气量控制,骨料温度检测手段的改进,混凝土生产过程检测系统,混凝土生产与输运车辆控制系统等.

Many quality problems of dam concrete construction appear in the production process. Concrete production consists of two steps,namely raw materials preparation and mixing production. If quality requirements in any step is dropped,the strength grade and mechanical indexes of concrete will also drop,which will easily cause quality defects,and will even cause engineering accident. However,high-quality dam of the third phase engineering in the Three Gorges Project was constructed,and the miracle of no crack dam was created. In the paper,the methods,measures and technology innovation of quality control in dam concrete production were elaborated from the aspects of concrete raw materials and concrete mixing production in the third phase of the Three Gorges Project. The quality control methods of cement,fly ash,admixtures and aggregates were elaborated at the aspect of concrete raw materials. At the aspect of quality control in concrete mixing and production,these measures of quality control were discussed,such as optimal design of concrete mix proportion,regular testing of weighing equipment,water defrosting for air cooler,secondary smashing stone for temperature measurement,concrete mixing processes,concrete machine-outlet temperature,slump,air content control,the improvement of aggregate temperature detection means,concrete production process testing system and concrete production-transport vehicle control system.