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近年来,我国引进了一定数量的混凝土输送泵(车),已在北京、上海、深圳等地逐步推广使用,然而在施工中经常发生混凝土堵塞的情况。对混凝土可泵送性的研究不够是一个重要原因。随着混凝土泵送方式的发展,对混凝土的工作性提出了较高的要求。一般说来,为了适宜泵送,混凝土必须满足下列要求。 1.混凝土工作性的一致。泵送混凝土必须严格按设计配方配料,并在进入输送泵之前搅拌均匀。 2.润滑层的存在。在泵送过程中要求混凝土能排出稀浆形成润滑层,并能持续保持,这是连续泵送的先决条件。因此,用输送管泵送混凝土,必须先输送稀浆,在管壁上形成润滑层,然后开始泵送混凝土。混凝
In recent years, China has introduced a certain number of concrete transfer pumps (vehicles), which have been gradually used in Beijing, Shanghai, Shenzhen, etc. However, concrete jams often occur during construction. The lack of research on the pumpability of concrete is an important reason. With the development of concrete pumping methods, higher demands are placed on the workability of concrete. In general, concrete must meet the following requirements for proper pumping. 1. The consistency of concrete workability. The pumped concrete must be formulated according to the design formula and mixed evenly before entering the transfer pump. 2. The presence of a lubricant layer. In the pumping process, the concrete is required to discharge the slurry to form a lubricating layer and can be continuously maintained, which is a prerequisite for continuous pumping. Therefore, to pump concrete with a transfer pipe, it is necessary to transport the slurry first, form a lubricating layer on the pipe wall, and then start pumping the concrete. Coagulation