Construction Precast Development
Precast News From China
precast technology developments
As an experienced engineer who has been working on bridge construction sites for decades, I am well aware that the appearance quality of precast T-beams is not only a facade project, but also a direct reflection of their internal quality.
A T-shaped beam with a smooth appearance and uniform color often means that its internal quality can withstand the test.
The beams with honeycomb and pockmarks on the surface and staggered cracks may also have hidden quality hazards.
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[Example 1] The high temperature of cement causes rapid loss of concrete slump.
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Ultra high performance concrete (UHPC) is a new type of cement-based composite material with ultra-high strength, ultra-high toughness, and ultra-high durability.
In the national standard “Ultra high Performance Concrete” (GB/T 31387-2025), it is officially defined as fiber-reinforced ultra-high strength concrete produced by using cement and mineral admixtures as cementitious materials, combined with aggregates, additives, high-strength micro steel fibers and/or non-metallic fibers, water, etc.
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I believe many friends have doubts about the retention of concrete test blocks for cast-in-place piles.
Here, I have consulted relevant specifications and excerpted the following:.
Concrete enterprises are mainly engaged in the production of commercial concrete and commercial mortar.
They must have certain hardware facilities (production line equipment, green environmental protection facilities, etc.
) and qualified technical personnel, and obtain the “Construction Enterprise Qualification Certificate” issued by the local government construction commission department before they can carry out product production and sales.
It plays a positive role in optimizing the comprehensive utilization of building materials resources, improving the quality of concrete products, and strengthening environmental protection in the basic construction of national roads and bridges and real estate development and construction.
There are many different grades of concrete products according to different formulas, such as C30, C40, C50, C60 and other series of products.
The sales price is mainly determined by the production cost, so its cost accounting and control determine the operating results and development momentum of the enterprise.
Abstract: The performance of concrete is influenced by various factors, especially the addition of active silica fume, which can effectively improve its performance and extend its service life, thus improving the quality of engineering.
This article reviews the effects of silica fume and its mixed additives on the durability and mechanical properties of concrete, and looks forward to the research prospects of silica fume on improving concrete performance.
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In today’s development of concrete technology towards high-strength, high-performance, and high fluidity pumping construction, it is necessary to explore the regularity of the relationship between the various elements in the concrete mix proportion and the workability, strength, and long-term performance of concrete.
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The generation and existence of bubbles on the surface of concrete not only affect the aesthetics of the project, but more importantly, it reflects that the quality of the project has not yet reached the standard specifications.
How to eliminate surface bubbles in concrete is a common and difficult problem encountered by many technicians and supervisors.
Therefore, engineering and technical personnel should pay sufficient attention to it.
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During the long-term use of building structures, concrete is susceptible to environmental erosion, load fatigue, and construction defects, which can lead to quality hazards such as reduced strength and crack propagation, threatening structural safety and shortening service life.
Although traditional concrete strength testing methods have high accuracy, they suffer from problems such as structural damage, time-consuming and labor-intensive testing, and high costs, making it difficult to meet the demands of modern engineering for efficient and non-destructive testing.
Rebound method, as a non-destructive, easy to operate, and cost-effective on-site testing technique, has become an important means of evaluating the quality of concrete structures.
The rebound method indirectly estimates the compressive strength of concrete by measuring the correlation between its surface hardness and rebound value.
It has the advantages of rapid detection, no damage, and repeatable operation, and is particularly suitable for large-scale surveys and construction process quality control.
However, this method still has certain limitations and requires further exploration of its application points in order to improve the level of engineering quality control.
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In engineering, different buildings have different requirements for concrete strength.
Generally, concrete strength is required to be higher in locations with higher loads, such as building skeletons, bridges, tunnels, etc.
, which play the main supporting role.
For the selection of concrete strength, it is necessary to consider the principle of meeting both the demand and the economy, in order to achieve maximum efficiency.
For buildings with specific requirements, it is necessary to fully consider a certain characteristic indicator of the concrete mix ratio.
A good mix ratio can fully utilize the performance of concrete, and mix design is the most basic task of concrete.
Although mix proportion design has made great progress, it has limitations for local use.
Different raw materials, climate conditions, transportation distances, and construction methods all have varying degrees of impact on mix proportion.
In mix proportion design, it is necessary to use specifications as the standard and adjust the calculated mix proportion based on factors such as construction site conditions, transportation distances, and climate conditions to obtain the optimal mix proportion.
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