Construction Precast Development
Precast News From China
precast technology developments
Place the concrete specimen onto the press, press a button, wait for it to crush, and take a reading – this is the complete understanding of strength testing by many people.
If it’s that simple, why can the data of the same specimen differ by several megapascals when pressed by different people?.
As an underground/semi underground municipal and building supporting structure, box culvert has the characteristics of large cross-sectional size, closed (or semi closed) structure, high concrete consumption, and complex exposed surface (inner wall+outer wall+top plate+bottom plate).
The core focus of maintenance is to control temperature difference, continuously moisturize, and balance internal and external synchronous maintenance, to prevent surface cracks and through cracks caused by insufficient humidity and large temperature difference, and to ensure that the concrete strength meets the standard and durability meets the design requirements.
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With the rapid development of commercial concrete, there is an increasing phenomenon of both supply and demand sides arguing over the low strength of structural concrete.
As the commercial concrete industry belongs to the buyer’s market, in order to timely recover payment and continue to cooperate with the demand side, most enterprises have to make concessions and passively bear some economic responsibilities.
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The strength of concrete is increased through the hydration reaction of cement.
Therefore, sufficient curing plays a crucial role in the strength growth of concrete and is also a key process to ensure the quality of concrete construction.
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1 Concrete can be transported on-site using tools such as handcarts, buckets, chutes (foundations), pumps, etc.
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(The following diagram shows the construction sequence of the first level retaining wall.
When the construction of the first level shore top earthwork meets the requirements of the second level retaining wall construction, the construction of the second level retaining wall can be carried out in the same order as shown in the figure below.
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In practical engineering operations, many practitioners are always confused about the concept of concrete strength.
Take C30 concrete, which has the highest frequency of use, for example, you will find many completely different numbers.
The design drawings indicate 30MPa, while the test block obtained 35MPa through pressure testing.
However, the value used for structural calculations was 14MPa, and the strength value obtained from core sampling became 26MPa.
What kind of relationship are all these numbers? It’s really confusing.
I don’t need to use my brain in that line, I just have a handle on it.
This is the boldness and boldness of a true engineer.
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Soil foundation is the fundamental load-bearing matrix of pavement structure, and it is also the core foundation that determines the uniform support effect of pavement.
Even if the surface layer and subgrade layer are perfect, once there are quality defects in the soil foundation (roadbed) itself, the long-term service life and performance of the pavement will lose its core guarantee.
As the second installment of a series of special topics, this issue introduces the engineering classification and core characteristics of roadbed soil, compaction quality control, treatment of special soils such as expansive soil and frost heave soil, and special measures for construction in humid soil conditions.
It provides technical references for interested road users.
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On April 9th, the national cement market experienced a small-scale decline, with Longyan, Nanping, Shenzhen, Chongqing, and Changdu falling by 10-20 yuan/ton.
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In 2026, it is not a low point for the concrete industry, but a life and death elimination race.
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