Figure 1 shows the scatter plot of the relationship between gas content and water reduction rate for 46 samples.
From the graph, it can be seen that the water reduction rate of the water reducer is roughly positively correlated with the air content, that is, as the air content increases, the water reduction rate of the water reducer will also increase.
Not only that, introducing air into concrete can also increase the cohesion of concrete and the lubrication effect between materials, improve the segregation and bleeding of concrete, and enhance the workability of fresh concrete [1].
Meanwhile, appropriate air entrainment in concrete can also improve its frost resistance, significantly enhancing its impermeability, resistance to chloride ion penetration, and carbonation resistance [2].
But if the air content is too high, it can also lead to too many holes in the concrete, making it less dense and reducing its strength.
Therefore, the current standard GB8076-2008 “Concrete Admixtures” [3] stipulates that the upper limit of the air content of high-performance water reducing agents is 6%.
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