Many concrete slabs have just been poured, and soon after, dense, spider like web like cracks appear on the surface, which are often attributed to problems caused by “untimely maintenance”.
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precast-tech
precast-tech
Current situation of steel ultra-high performance concrete composite bridge deck pavement
To solve the problems in the application of orthogonal anisotropic steel plate ultra-high performance concrete composite bridge deck pavement in China, a survey was conducted on the current status of ultra-high performance concrete composite bridge deck pavement technology at home and abroad through literature review, actual bridge investigation, and on-site testing.
Field investigations were also conducted on the service conditions of 9 representative composite bridge deck pavements in China.
The results show that: 1) China’s steel UHPC composite bridge deck has differences in materials and structures compared to the Netherlands and Japan, mainly due to the dense arrangement of shear studs between the UHPC layer and the steel bridge deck; 2) At present, the UHPC composite bridge deck pavement in China mainly suffers from diseases such as mixture segregation, pavement cracking, rutting and displacement, and expansion joint cracking.
Subsequent research should focus on the bonding between UHPC and the wear layer, the anti rutting and anti cracking of asphalt wear layer, and the prevention of mixture segregation.
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Precautions for compounding concrete admixtures
At present, in the process of compounding production, only simple production techniques are mastered or the improvement of concrete properties by admixture products is pursued unilaterally, but the influence of some components and addition amounts in compounding on concrete strength and durability is ignored.
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Comparison and selection of preloading methods for prestressed concrete continuous beam 0 # block
Preloading is used to test the strength, stiffness, and stability of the 0 # block support of prestressed concrete continuous beams.
The preloading of the 0 # block support for prestressed concrete continuous beams is an essential key process and the first step in the safe construction of prestressed concrete continuous beams.
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Prevention and control of common quality problems in the construction of large volume concrete in hydraulic engineering
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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Quality Control of Concrete in Water Conservancy Engineering Construction
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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People’s Court Reports Evaluation of Horizontal Monopoly Agreement Case of “Concrete Enterprise”
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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What are the problems with adding water to concrete without authorization?
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:.
Why does concrete turn white frost?
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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Practical analysis of concrete and reinforced concrete engineering measurement in the preliminary budget of construction projects
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:.