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conpd0523
How to deal with the adverse effects of coagulants in sand on concrete
In the context of environmental protection requirements, the widespread use of coagulants in the production of mechanism sand has led to the prominent problem of residual coagulants in sand.
The residue of coagulants in sand is “destructive” to concrete: on the one hand, organic coagulants (such as polyacrylamide) compete with polycarboxylate superplasticizers for cement particle adsorption sites, leading to the “failure” of the superplasticizer; On the other hand, inorganic coagulants such as polyaluminum chloride can introduce chloride ions and sulfate ions, which can damage the durability of concrete.
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Research on Key Factors and Strategies for Quality Control of Pre mixed Concrete
With the acceleration of urbanization and the vigorous development of the construction industry, ready mixed concrete has been widely used in various construction projects due to its high production efficiency and stable quality.
However, the quality of ready mixed concrete is affected by various factors.
If not properly controlled, it may lead to quality problems such as insufficient concrete strength and cracks, seriously affecting the quality and safety of construction projects.
Therefore, studying the key factors and strategies for quality control of ready mixed concrete has important practical significance.
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Experimental study on anti alkali high-performance concrete and suggestions for mix design
Literature research shows that the main alkaline products include salts such as CaCO3, NaSO4, CaSO4, and K2SO4.
At present, the main methods for inhibiting alkali bleeding both domestically and internationally are: firstly, by improving the overall treatment of the internal composition of concrete, that is, by preparing high-performance alkali resistant concrete; The second is the surface treatment method of coating the concrete surface.
The surface coating materials used in literature include cement-based materials, adhesives, mortar, and organic coatings.
Overall, the overall treatment method can better improve the anti alkali properties of concrete by changing its internal composition.
Literature research has shown that using low water cement ratio concrete and adding certain active mineral admixtures can improve the impermeability of concrete to a certain extent, thereby playing a role in anti alkali leaching.
However, there is no clear experimental specification for the component design of this anti alkali admixture both domestically and internationally.
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Definition of Pre mixed Concrete Delivery Inspection and Engineering Entity Inspection
(1) According to Article 9.
1.
1 of “Ready mixed Concrete” GB/T14092-2012, the quality inspection of ready mixed concrete is divided into factory inspection and delivery inspection.
The sampling and testing work for factory inspection shall be borne by the supplier, and the sampling and testing work for delivery inspection shall be borne by the purchaser.
When the demand side does not have the technical qualifications for testing and personnel, both parties can negotiate and entrust a qualified inspection unit to undertake it, and this should be clearly stated in the contract.
Article 9.
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2 stipulates that the delivery inspection results shall be notified to the supplier within 10 days after the end of the test.
Article 9.
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3 stipulates that the quality acceptance of ready mixed concrete shall be based on the delivery inspection results.
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Precautions for Construction of Commercial Concrete
To ensure the uniformity of concrete, the mixer truck should run at high speed for 20-30 seconds before unloading, and then discharge in reverse.
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Ideas and strategies for preventing and controlling concrete cracks
Concrete, as the most widely used building material in modern civil engineering, has always been a concern for its cracking problem.
Extensive engineering practice and research have shown that cracks are an inherent characteristic of concrete materials that cannot be completely eliminated, but can be effectively controlled through scientific means.
According to their causes, concrete cracks can be mainly divided into two categories: structural cracks and non structural cracks, with the latter accounting for more than 80% of engineering cases.
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American Standard Concrete Design, Phase 4- American Standard Wind Load (Part 2)
When working on overseas projects, wind load calculation is often the “first hurdle” for engineers.
This issue will focus on the specific implementation of wind loads on American Standard (ASCE 7) concrete structures in Midas Gen overseas version, and compare it in detail with the national standard (GB 55001-2021) to help you easily cope with overseas project challenges.
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The efficient concrete conveying and pouring system developed by Beijing Construction Machinery Institute has been successfully applied in
Beijing Construction Mechanization Research Institute Co.
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aims to meet the urgent needs of large-scale infrastructure construction such as water conservancy and hydropower, wind power, highways and railways, bridge and tunnel engineering, and has developed a high-efficiency concrete conveying and pouring system.
It has successfully achieved a large number of engineering applications and has been applied in batches to many national key engineering projects such as the Century Engineering Pinglu Canal, and exported to international projects such as the Kekai Hydropower Station in Angola.
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The review meeting for the group standard “Technical Regulations for Integration and Application of Intelligent Management System for
Recently, the review meeting of the group standard “Technical Regulations for Integration and Application of Intelligent Management System for Concrete Construction” (hereinafter referred to as the “Regulations”) managed by the China International Association for the Promotion of Science and Technology was successfully held in a combination of online and offline forms.
Industry experts from universities, research institutes, construction enterprises, and supervision units form a review committee to comprehensively evaluate the standards.
Relevant leaders of the Standardization Working Committee of the Science and Technology Promotion Association attend the meeting.
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