Concrete mixer pump has brought construction industry great convenience, but improper use of concrete pumps probably causes construction cracks. Next, Daswell machinery experts will help you analyze the reasons for pump concrete cracks.Henan Daswell Machinery Co., Ltd,is a professional manufacturer and trader specializing in the research, development and production of construction machinery for nearly 30 years. Our main products are as follows:concrete mixing plant, concrete batching plants,concrete mixer,blocking making machine,concrete pump,etc.
First: temperature crack
Cement produces a lot of heat in hydration process, thus increasing the internal temperature of concrete. In accordance with relevant provisions of our country construction acceptance specifications, concrete pouring temperature is 28 ?, which will make the concrete internal temperature reach about 65 ?. If we do not take any measures to reduce the hydration heat of cement, concrete internal temperature sometimes even higher. Cement hydration heat can emit heat by 50% in 1~3 days. With the heat accumulation, the concrete maximum temperature will appear approximately in 3~5 days.
Since diffrent heat sinking conditions of the concrete surface and inside, it will form different temperature and cause temperature stress. When this stress exceeds concrete internal and external binding force (including concrete tensile strength), it will cause cracks. It is generally believed that when the temperature difference between inside and outside of concrete more than 25 ?, it easily causes cracks. The crack always appears in 3~5 days after the concrete pouring. The crack looks very thin in the early time, and then it may expand with time, even throughout.
Second: concrete material & concrete production
There are many cases causing cracks, such as poor water retention, big shrinkage, unreasonable aggregate grading; unreasonable concrete mixture ratio, too large water-cement ratio, improper control of concrete slum and so on.
Third: reinforcement ratio
If reinforcement ratio is higher, when stone size is too large, concrete is often difficult to perfuse, which makes its homogeneity poor and easily cause cracking due to uneven shrinkage.
The above suggestions are offered by Daswell Machinery experts. We hope the advice can give you great help. If you are interested in any of our products, such asportable concrete mixer mobile block machine, diesel concrete mixers, electric portable concrete mixer, etc. Please feel free to contact us.
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