Why is there a gap in concrete strength?

Release time:2023-07-06

Ready-mixed concrete has developed rapidly in urban and rural areas in China due to its convenient construction and reliable quality. In recent years, engineering quality accidents caused by concrete quality problems are common, such as strength not reaching the design level, abnormal cracking, etc., which have caused great troubles to all parties in the project. The strength of concrete is significantly affected by the water cement ratio, if the concrete water or cement, slag, fly ash a component once the fluctuation, will cause the fluctuation of concrete strength. Since the quality acceptance of concrete is based on its 28-day compressive strength as the standard, the quality feedback of production has a large lag, so the quality control of the production process is particularly important. At present, the mixing station generally obtains the corresponding concrete slump under a certain water-cement ratio by matching and testing. In the production process, the purpose of determining the water-cement ratio is achieved by controlling the slump of the concrete. In fact, through a large number of experimental analysis of the properties of raw materials such as sand, stone and cement, it is found that the slump of concrete sometimes does not really reflect its actual water consumption or water-cement ratio. In daily production, such a phenomenon often occurs. The slump of concrete is well controlled. At the same time, the strength of cement mortar for 28 days is also very stable, while the strength of concrete still fluctuates greatly.

Key words: Why is there a gap in concrete strength?


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