(1) Cement: Helin P · O42.
5 cement, with a 28 day cement strength of 49.
3MPa;.
conpd0523
Research on the technical path of optimizing the proportion of admixtures in early crack control of concrete
As a commonly used material in construction engineering, concrete is one of them.
Early crack problems always pose challenges to construction quality and structural safety.
The formation of cracks is often closely related to factors such as hydration heat and shrinkage.
The introduction of admixtures has opened up an effective technical path for concrete crack control.
By reasonably screening and optimizing the types and ratios of admixtures, the crack resistance and durability of concrete can be significantly improved.
This article will study the role of admixtures in early crack control and their optimization schemes, analyze the effects of different types of admixtures on concrete performance, and then propose corresponding technical means.
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The Influence of Concrete Raw Materials on Concrete Quality
The quality of concrete construction will lead to quality defects or cracks in concrete engineering.
Analysis suggests that this is because the deformation of concrete raw materials (including cement stone and coarse and fine aggregates) is constrained, resulting in internal stresses greater than the tensile strength of the materials.
The quality of freshly mixed concrete mainly includes its setting time and workability.
When analyzing the impact of concrete raw materials on concrete quality, several aspects can be explored, including aggregates, cementitious materials, additives, and mixing water.
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Common problems in the factory inspection and application of concrete antifreeze agents
The composite antifreeze pumping agent currently used by concrete companies is generally composed of antifreeze, early strength, water reducing, and air entraining components.
Among them: (1) Antifreeze mainly lowers the freezing point of liquid phase in concrete; (2) The dosage of early strength agent increases the early strength of concrete, enabling it to reach or exceed the critical frost resistance strength of concrete as soon as possible.
(3) Water reducing agents can reduce the water consumption of concrete and minimize concrete frost damage.
(4) Air entraining agents can alleviate the stress damage caused by ice frost heave and improve the early frost damage resistance of concrete.
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Calculation rules for concrete and reinforced concrete (6)
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The compounding effect of concrete admixtures
It means that two or more types of concrete admixtures produced by different brands and manufacturers are mixed together in different proportions, and their concrete workability and durability cannot be achieved by any single admixture.
This is the compounding effect of admixtures.
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How does the curing temperature affect the interlayer bonding strength of 3D printed concrete?
With the increasing aging population and the pressure of global climate change, it is inevitable for the construction industry to develop towards automation and energy conservation.
3D concrete printing technology can automatically and accurately lay materials to the required locations, saving labor and materials, and is a new way for the industry to upgrade.
But it has a key issue – the bonding strength between the printing layers is not sufficient, which can result in inconsistent strength and durability of the concrete, and also shorten the service life of the building, which has always constrained the practical application of this technology.
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The inconspicuous amount of stones used is actually a “magic mirror” for the quality of concrete
Complete set of automatic calculation tables by 2025 (including concrete, rebound, geotechnical, steel reinforcement, aggregate, cement, fly ash, mix proportion, etc.
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How to identify and handle concrete frost damage
According to the local temperature data for many years, when the daily average outdoor temperature remains below 5 ℃ for 5 consecutive days, concrete construction should enter the winter season.
Therefore, the winter construction period for concrete can be determined based on historical meteorological data.
In the autumn and winter seasons, the specific date for winter construction of concrete is from the initial day when the temperature remains below 5 ℃ for 5 consecutive days to the final day when the temperature remains above 5 ℃ for 5 consecutive days in the spring of the following year.
However, it should be noted that in early winter or early spring, sometimes a sudden cold wave strikes and the temperature drops below 0 ℃.
After the cold wave, the temperature rises again.
This situation often goes unnoticed by construction personnel, and insulation and windproof measures are poor, resulting in more severe concrete freezing damage.
Concrete frost damage can be divided into the following three types.
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Must see for winter construction! Concrete antifreeze knowledge, fully mastered from principle to practical operation
The sudden drop in winter temperature makes concrete construction the most afraid of “freezing”.
Once frozen, it not only leads to a significant decrease in strength, but also may cause problems such as cracks and sanding, seriously affecting the quality of the project.
Previously, we mentioned the key points of antifreeze in winter maintenance.
Today, we will specifically break down the core knowledge of “concrete antifreeze”, from “why it freezes” to “how to prevent it at different low temperatures”, and then to “how to use antifreeze”, to help everyone get the antifreeze details in place.
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