Precast News From China
The structure of various parts of a certain large-scale water conservancy hub project is mostly large in volume.
We mainly focus on the common quality problems and prevention measures of large volume concrete to ensure the high quality of the project.
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Strictly follow the concrete mix proportion sheet provided by the laboratory and approved by the supervisor for batching, and it is strictly prohibited to change the concrete mix proportion without authorization.
The construction unit must use accurate weighing equipment for production and regularly check the weighing equipment according to the instructions of the supervisor.
We insist on weighing each plate of sand and gravel, and do not advocate the volumetric method of marking with small carts.
In addition, regular spot checks should be conducted on mixing time, feeding sequence, concrete slump, and whether the concrete is segregated.
In larger projects, construction units should use computer-measured mixing plants to reduce human factors and ensure the design strength of concrete.
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In March 2017, a certain Fifth Construction Engineering Group Co.
, Ltd.
(referred to as Fifth Construction Company) signed a commercial concrete purchase and sales contract with Jianmou Concrete Co.
, Ltd.
(referred to as Concrete Company), agreeing on the supply price of commercial concrete.
In September 2018, the two parties signed a supplementary agreement, which increased the price of concrete by 90 yuan per cubic meter.
From then until April 2020, the concrete company has supplied more than 5000 cubic meters of concrete to the Fifth Construction Company.
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In summer, cities tend to be hotter, which leads to a problem for construction workers on construction sites.
When doing all lightweight concrete construction, road and bridge repairs, the materials quickly dry up, making construction difficult.
Moreover, the completed parts are prone to cracking.
Therefore, some friends on projects will add water to the materials themselves for the convenience of construction, in order to keep them moist.
But do you think this approach is right? Let’s not rush to say right or wrong for now, read on:.
The appearance quality of concrete is a direct reflection of its quality.
The uniformity and oiliness of the surface color of concrete are increasingly concerned by construction contractors and owners, and their requirements are also increasing.
It has gradually become an important economic factor.
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Concrete and reinforced concrete engineering is one of the sub items with the highest proportion of construction project cost (about 25% -35% of the total civil engineering cost), and the accuracy of its quantity calculation directly affects the accuracy of project cost.
The project content covers:.
In the laboratory of China Railway Ninth Bureau Group Engineering Testing Co.
, Ltd.
, groups of concrete test blocks make a dull sound under the press.
Weng Shuai’s gaze was focused, staring closely at the jumping data on the screen.
In the railway engineering testing and inspection industry, every data measurement and inspection report is related to the stability of steel rails, the safety of tunnels, and the durability of bridges.
“This 40 year old senior technician spoke calmly, with fingertips tracing through the dense inspection reports.
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Many people believe that stone powder in sand is harmful to concrete, so they try their best to remove it.
Little do they know, a moderate amount of stone powder can also have a positive effect.
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The concrete industry has undergone decades of development, and the mix design and production process have become relatively mature.
However, the current quality control of concrete still faces core difficulties – the quality of raw materials is uneven and fluctuates frequently.
If the mix ratio is not adjusted in a timely and accurate manner, it is easy to cause various quality problems.
For example, concrete mixtures are often blocked due to poor aggregate wrapping, segregation, bleeding, or excessive loss of slump over time; Fluctuations in raw materials may also result in substandard strength or large strength dispersion of concrete test blocks, leading to substandard engineering quality.
With the increasing efforts in environmental control, unstable raw material quality has become a norm in the industry.
Therefore, understanding the current status of raw materials, adapting production processes to fluctuations in raw materials, and improving concrete quality are of great practical significance.
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Sodium gluconate is mainly used as an efficient retarder in concrete, which can delay the setting time of concrete, improve workability, and have a small impact on strength development.
It is one of the commonly used chemical additives in concrete engineering.
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