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2 Technical measures for controlling concrete cracks in building construction
2.1 Strengthening the design of concrete structures during the design of concrete structures, it is best to choose low- and medium-strength concrete and try to avoid using high-strength concrete. In order to effectively control the surface shrinkage cracks during the construction of large-volume concrete, generally, the amount of reinforcing steel can be appropriately distributed on the surface of the platform. Although this method cannot effectively prevent the generation of cracks, it can effectively reduce the temperature and the width of the cracks, increases the integrity of the structure.
During the construction of large-volume concrete, it is best to set horizontal construction joints and perform block processing according to the requirements of temperature cracks, and also set up the necessary connection methods.
2.2 Reasonable selection and proportion of concrete raw materials
In the concrete preparation process, if the water absorption rate is greater than the amount of aggregate added, the shrinkage of concrete is increased to a certain extent; for aggregates with good gradation and large particle size, it can be appropriately reduced the amount of cement slurry in concrete, so can effectively reduce the shrinkage of concrete.
By adding fly ash to concrete, not only the amount of cement and hydration heat be effectively reduced, but also the water can be reduced, and the volume shrinkage of the concrete itself can be effectively reduced.
In addition, adding high-efficiency water-reducing agent or fly ash to the concrete enables the concrete to have better pumpability, impermeability, workability, and segregation resistance, avoid bleeding, and reduce cracks.
During the design process of concrete mix ratio, designers are required to go deep into the construction site and adjust the operation level, supervise the formwork operation and pouring technology, and section of the components according to the actual situation. It is necessary to set the concrete slump scientifically and reasonably, and adjust the mix ratio according to the quality of the stone and sand materials at the construction site. By improving the aggregate gradation, adding high-efficiency water reducing agent or fly ash can effectively reduce the amount of cement and the heat of hydration.
To be continue…
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