Analysis of the reasons for the rebound of concrete slump in winter

However, although polycarboxylate based admixtures have solved the requirements for high-rise pumping and durability of ready mixed concrete, they are highly sensitive to fluctuations in concrete raw materials and environmental conditions, leading to various problems during the construction of ready mixed concrete.

Concrete Plate Anchors

If there is a phenomenon of rebound in the slump of ready mixed concrete, especially in winter, this phenomenon is more common, and the ready mixed concrete mixing plant also solves it vaguely every time.

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What are the precautions for winter concrete construction? How to use antifreeze?

According to Chapter 7 of the national standard “Code for Construction and Acceptance of Concrete Structures” (GB50204), based on 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.

At this point, the first day when the temperature remains stable below 5 ℃ for 5 consecutive days is considered the initial day for winter construction.

Similarly, when the temperature rises, the end of winter construction is the day when the temperature remains stable above 5 ℃ for 5 consecutive days.

Swift Lift Foot Anchor

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【 Quick Enjoyment Standard 】 Essential for the Industry! Overview of the latest national and industry series standards for cement concrete

This document specifies the test methods for the volumetric density, water absorption rate, compressive strength, axial compressive strength, static compressive modulus, flexural performance (flexural ratio ultimate strength, flexural ultimate strength, and flexural modulus), tensile strength, impact strength, anchor rod pull-out force, embedded bolt sleeve pull-out force, frost resistance, and shrinkage rate of non load bearing components of ultra-high performance concrete.

Plastic Nail Plate

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The influence of coarse aggregate on the performance of concrete

For a long time, many scholars have conducted in-depth research on other components of concrete, such as cementitious materials and additives.

Even for fine aggregates, due to the increasing scarcity of natural sand in recent years, research has been strengthened, leading to rapid development in the production and use of mechanism sand.

However, coarse aggregates, which are the largest volume component of concrete, have not received sufficient attention.

With the development of concrete technology, the requirements for concrete performance are also increasing, and the impact of coarse aggregates on concrete performance is becoming increasingly prominent.

A comprehensive and in-depth exploration of the characteristics of coarse aggregates on concrete performance has become an urgent issue for concrete workers.

Swift Lift Foot Anchor

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Essential for laboratory managers: Quality control throughout the entire process of concrete production

Transform thinking and shift the focus of work from post pouring testing and inspection to pre pouring mix design and raw material control, and integrate them throughout the entire construction process.

By optimizing technology and refining management, the pouring of high-quality concrete becomes “simpler and more controllable”, thereby naturally reducing the labor intensity of workers.

Concrete Plate Anchors

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Let the construction unit take a look, early maintenance is crucial for the quality of concrete

The earlier the curing period after pouring concrete, the greater the impact on the concrete.

In practice, it has been found that if a standard curing of 7 days can be guaranteed, the compressive strength of concrete at 28 days can basically reach about 90% of the standard curing.

If no curing measures are taken for concrete test blocks, the impact on the strength of low strength grade concrete is greater than that of high strength grade concrete.

The reason is that low strength grade concrete has low early strength, low compactness, and easier internal moisture loss, resulting in a decrease in later hydration degree.

The engineering entity structure is much larger than the test block, and the surface curing is insufficient.

The degree of decrease in internal concrete strength is smaller than that of the test block, but the loose and powdery phenomenon of the surface concrete directly leads to low rebound strength.

Steel Rebar Chairs

Taking C30 as an example, it is common for engineering entities to have a rebound strength lower than the standard curing specimen by more than 5MPa without curing.

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Application of Rebound Method in Quality Inspection of Solid Concrete

At present, it is very important to use the rebound method to detect the construction quality of concrete structures in construction projects.

The principle is mainly based on the hardness and strength of concrete.

Under the action of elasticity, the impact force of the steel hammer is transmitted to the surface of the concrete, and the initial function is redistributed.

Magnetic Thread Disc

In the case of plastic or residual deformation, the concrete absorbs some of its capacity, and other capacities will reach the heavy hammer to ensure the rebound height of the steel hammer.

Combined with the positive correlation between this height and the strength of the concrete, the strength of the concrete material itself can be effectively calculated.

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The concrete giant has a net loss of over 190 million and a debt to asset ratio approaching 70%!

In October 2025, the first three quarters performance announcement disclosed by Western Construction showed that the company achieved a revenue of 13.

881 billion yuan, a year-on-year decrease of 7.

57%, and a net profit attributable to the parent company was a loss of 198 million yuan, a significant year-on-year decrease of 2141.

86%.

The performance of turning from profit to loss reflects multiple pressures on the company’s management.

From the financial data perspective, the deterioration of the profit side is particularly prominent, with a weighted average return on equity as low as -2.

44% in the first three quarters and a gross profit margin of only 6.

57%, further shrinking from 8.

45% in the same period last year and far below the industry average.

Rebar Saddles

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Research progress on 3D printing geopolymer concrete in J. Mater. Sci

With the urgent global demand for sustainable development and intelligent construction, the construction industry is actively seeking low-carbon and efficient innovative solutions.

Swift Lift Void Former

3D printing concrete technology has emerged, which does not require templates and can freely form complex structures, greatly improving construction efficiency and reducing material waste.

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