Construction Precast Development
Precast News From China
Ju Rong adheres to the concept of “Ju Xin follows the Tao, Rong Yuan benefits others” and always puts product quality first.
In order to implement quality work, Xinqiao Company has recently carried out job recognition and practical briefing for technicians and mixing plant operators, unifying standards and processes, and solidly doing a good job in every concrete mix.
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The main components of concrete are cement, admixtures, coarse and fine aggregates, water, and additives.
In the mixing of cement and concrete, the main component of cement is CaO.
After hydration, Ca (OH) 2 is generated.
The carbonation of concrete refers to the chemical reaction between Ca (OH) 2 in concrete and CO2 in the air.
CO2 gas in the air penetrates into the concrete and reacts with alkaline substances to produce carbonate and water.
The process of reducing the alkalinity of concrete is called concrete carbonation, also known as neutralization.
Its chemical reaction is: Ca (OH) 2+CO2=CaCO3+H2O, producing neutral carbonate CaCO3.
Unbaked concrete is alkaline, and the minimum (critical) alkalinity for steel bars in concrete to remain passive is a pH value of 11.
5.
Carbonized concrete has a pH value of 8.
5-9.
5, indicating that carbonation reduces the alkalinity of concrete.
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Shocked concrete is a type of concrete, which is also made by mixing sand, stone, cement, water, and admixtures in a certain proportion.
However, shotcrete is a type of concrete that is sprayed at high speed through a pipeline using spraying machinery to solidify and harden on the sprayed surface.
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In order to strengthen the quality control of engineering construction in our city, standardize the production, testing, and delivery management of ready mixed concrete throughout the entire process, the Municipal Commission of Housing and Urban Rural Development has officially released a new version of the local engineering construction standard “Pre mixed Concrete Quality Control Standard” (DBJ50/T-038-2026).
The standard will be officially implemented on October 1, 2026, and the original DBJ50/T-038-2018 will be abolished simultaneously.
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3D concrete printing (3DCP) has become one of the core directions of construction industrialization due to its advantages of template free, complex configuration free molding, and fine material utilization.
However, from prototype display to load-bearing structure application, material anisotropy and high mechanical performance variability have always been the core bottlenecks – there are huge differences in printing equipment, mix proportions, and process parameters around the world, and there is still no unified safety factor for structural design sub items.
If a single conservative value is taken directly in the most unfavorable direction, it will lead to larger component dimensions and an increase in hidden carbon; If control is relaxed, there will be no evidence to support structural risks.
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Industry iteration accelerates, technological innovation continues! In the current context of intensified fluctuations in raw materials, upgraded construction standards, and low-carbon cost reduction, the mix design, which is the core of concrete production, is undergoing a disruptive change.
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The number of certified personnel does not meet the requirements of standardized management, and the laboratory director has not registered with the quality supervision station.
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In the concrete industry, concrete with a strength grade of C60 or higher is generally referred to as high-strength concrete, while concrete with a strength grade of C100 or higher is referred to as ultra high strength concrete; Concrete with a pumping height exceeding 200m is called super high-rise pumped concrete.
Super high-rise pumped concrete with high strength, ultra-high strength, and pumping height greater than 200m, due to its low water cement ratio, requires a large amount of total cementitious material in a single cubic meter of concrete, resulting in high concrete viscosity.
Therefore, the pumping pressure is high and the pumping construction is difficult, bringing a series of technical challenges to the entire construction pouring process.
This article provides some insights and experiences on solving the viscosity of high-strength and ultra high strength concrete for the vast number of concrete professionals, in order to entertain readers.
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My own level is limited.
If there are any unclear expressions or inaccurate descriptions, I hope colleagues and experts can give me more guidance.
In this issue, I will discuss with you the key points of construction quality control from several aspects such as concrete construction, steel processing, interior construction, and exterior construction.
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