Precast News From China
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Concrete and asphalt are the ground foundation materials for various living, leisure, and sports venues.
The requirements and standards for concrete or asphalt foundations vary greatly depending on the purpose of the venue, which determines the safety, durability, user experience, and cost of the venue.
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Commercial concrete is greatly affected by various factors during delivery and use, especially in unfavorable conditions such as windy and dry conditions in autumn, low humidity, and large temperature differences between day and night.
If effective measures are not taken during construction and maintenance, it may cause quality problems.
Therefore, special attention should be paid to autumn concrete construction.
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✨ Core function: This development tool is the third tool in the practical data manual for construction engineering, used to quickly query data on concrete strength grade, durability, mechanical properties, etc.
, making it convenient for engineering personnel to quickly access and estimate structural loads.
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Reading method: click the above “special treatment for difficult and miscellaneous building problems” to enter the official account, and then click the above attention, all the contents of this official account will be displayed.
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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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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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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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(1) According to Article 9.
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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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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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