November 2025 (11.
17-11.
21).
Construction Precast Development
Precast News From China
For the convenience of template production, compression members generally adopt square or rectangular cross-sections.
When using a rectangular section for eccentrically compressed components, the long side of the section is arranged in the direction of the bending moment, and the ratio of the long side to the short side is generally 1.
5 to 2.
5.
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Abstract: This article conducts comparative experiments on various factors that affect the elastic modulus of high-strength concrete, and analyzes the effects of factors such as coarse aggregate, sand ratio, water cement ratio, and slump on the elastic modulus of C100 high-performance concrete.
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The torsional failure mode of reinforced concrete components is mainly related to the amount of torsional steel reinforcement.
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In the past decade, experts and scholars have clearly pointed out that the strength and durability of concrete mainly depend on the characteristics of the cementitious matrix and the bonding properties between the cementitious matrix and aggregates.
The bonding properties between the matrix of the cementitious system and the aggregate depend on the characteristics of the matrix of the cementitious system.
Therefore, this article verifies whether the optimal stacking state of various materials in the cementitious system has a beneficial effect on the formation of concrete structures, and ultimately aims to broaden the design ideas of mix proportions and improve the economic benefits of concrete production enterprises.
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Concrete, as the most widely used building material, occupies a core position in China’s infrastructure field.
In 2021, China’s concrete production reached a peak of 3.
3 billion cubic meters, of which fine aggregates accounted for over one-third.
However, as a traditional fine aggregate, natural river sand is a non renewable resource, and its mining not only incurs high costs, but also faces the problem of increasingly depleted resources.
In this context, mechanism sand has become an ideal alternative material due to its abundant resources, simple preparation process, and economic advantages.
However, its inherent problems such as strong particle angularity, poor gradation continuity, and high stone powder content limit its application in high-grade concrete structures such as bridges.
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Nowadays, the concept of “involution” has evolved into a synonym for vicious competition and internal friction in development, and is showing an increasingly fierce trend in the concrete production industry.
Concrete production enterprises are deeply trapped in the dilemma of internal competition, and the vicious cycle of low price competition is squeezing their profit margins.
Some enterprises even use unqualified raw materials to reduce costs, causing quality hazards.
The concrete industry faces severe homogenization competition, insufficient innovation drive, and is trapped in a closed loop of “low-level repetitive construction – declining profits – reduced technology investment”.
The key to cracking the industry’s internal competition lies in getting rid of low-level competition traps.
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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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