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 ℃.

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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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Small crafts include the “Great Ability” series -18. The joint surface between new and old concrete is chiseled with a flower hammer

The flower hammer chiseling tool consists of a high-strength alloy hammer head and an electric impact device (such as an electric hammer or pickaxe).

It forms a uniform “lychee surface” texture on the concrete surface through high-frequency impact, breaking the smooth surface structure and achieving a chiseling effect with a depth of about 1-5 millimeters.

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Spray type 3D concrete printing system: Overcoming pain points in reinforced components and achieving high-precision automated molding

Shimizu Construction Co.

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, a Japanese construction engineering and design company founded in 1804, has developed a spray type 3D concrete printing system specifically designed for the construction of large-sized curved reinforced components.

Plastic Rebar Chairs

This system integrates a nine degree of freedom gantry robot and a material spraying simulation system, which can pre verify the forming characteristics of sprayed materials.

This technical solution can achieve high-precision automated production of reinforced structural components and large components with complex geometric shapes, which is difficult to achieve with traditional material extrusion 3D printing technology.

The material injection simulation system carried by the system is jointly developed by Shimizu Construction and the Computational Engineering and Robotics Laboratory (CERLAB) led by Professor Kenji Shimada from the Department of Mechanical Engineering at Carnegie Mellon University.

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Literature Sharing 50: Composite Effects of Modified Recycled Concrete Aggregates and Metakaolin on High Strength Concrete Production:

In the current transition of urban construction towards high-altitude and green construction, high-strength concrete (HSC) has become the core material of super high-rise buildings due to its excellent mechanical properties.

However, the resource consumption and carbon emissions problems brought by traditional production modes are becoming increasingly prominent.

PVC Chamfer

How to achieve sustainable development of high-strength concrete through the substitution and performance optimization of recycled materials? The latest research provides an innovative answer that balances performance and environmental protection through the composite application of modified recycled concrete aggregates (MRCA) and metakaolin (MK), combined with machine learning quantitative analysis.

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The influence of antifreeze on the mechanical and durability properties of concrete

The winter temperature in the northwest region of China is relatively low, and winter construction in cold areas can have adverse effects on the various properties of concrete.

Long term exposure to cold environments can increase the porosity and decrease the compactness of concrete, making it loose and brittle, seriously affecting its mechanical and durability properties.

Adding antifreeze can effectively lower the freezing point of liquid phase water in the internal pores of concrete, allowing concrete to undergo hydration reactions well under low temperature conditions, thereby significantly improving the frost resistance of concrete.

Therefore, researching high-performance antifreeze agents to improve the mechanical and durability properties of concrete in cold regions is of great practical significance.

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The influence of six types of inferior fly ash on the performance of concrete

The residual amount of the original coarse ash sieve is relatively large, containing a lot of impurities and a large loss on ignition, so the actual effect cannot be well reflected.

In view of this, the concrete made from it does not have ideal fluidity, and its water retention and cohesion do not meet the requirements, which will have a great impact on the quality of fresh concrete; Due to excessive water demand, the actual water consumption per unit volume of concrete may exceed the expected water consumption, resulting in an increase in water cement ratio, a decrease in compressive strength grade, and a serious weakening of the durability of hardened concrete.

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