The torsional failure mode of reinforced concrete components is mainly related to the amount of torsional steel reinforcement.
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The Effect of Grading Efficiency of Cementitious Materials on Concrete Strength
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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The influence of mechanism sand mixed with stone powder on the performance of C50 bridge concrete
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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Laboratory under the “involution” of the concrete industry
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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The Influence and Suggestions of Air Content on Concrete in Water Reducing Agent Testing
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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Is there a total cracking in the concrete floor? Is it the ‘pot’ of materials or the ‘pit’ of construction?
The ground has cracked again! “- This is probably one of the most headache inducing issues for countless homeowners, construction workers, and flooring professionals.
Those irregular turtle cracks not only affect aesthetics, but also pose hidden safety hazards.
At this moment, a classic “throwing the pot” battle will unfold: the material supplier says it’s because the construction was not done well, and the construction party says it’s because the material quality is not good.
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Once explain the concrete standard curing test block and the test block under the same conditions, it is recommended to save it!
During construction, the retention of concrete test blocks is divided into standard curing test blocks and test blocks under the same conditions.
The reason why the testing of concrete test blocks requires both standard curing and the same conditions is that the two represent different meanings and play different roles, and cannot be simply or mutually denied.
Both must be qualified.
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How is the phenomenon of concrete “hard shell” formed?
The phenomenon of concrete hard shell refers to the rapid solidification of the surface to form a “hard shell” after pouring, while the interior is still in a plastic state.
Subsequently, problems such as sanding, cracking, and insufficient strength are prone to occur.
The core cause can be summarized as surface moisture imbalance+uneven hydration reaction.
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How to control the quality of reinforced concrete protective layer, five countermeasures
During the construction process, the deviation of the reinforcement protection layer of reinforced concrete structural components directly affects the mechanical properties and durability of the reinforced concrete components, which is related to the safety and service life of the building.
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