Due to the extensive use of industrial by-products and waste materials in the cement production process, the adaptability of admixtures has become increasingly prominent. This requires the development of different types of admixtures for different gelling materials. For example, polycarboxylic acid admixtures, according to market demand, will develop varieties that meet various requirements by changing the branching method, and facilitate engineering use and quality control. Admixtures for the development of high-strength, anti-aging At present, the strength of concrete is continuously increasing, and admixtures play a significant role in improving the performance of concrete. In the future, it is necessary to continuously develop admixtures for high-strength ultra-high-strength concrete.
Concrete admixtures are called admixtures. In the process of disposing and mixing concrete, it is necessary to add some products according to the city design requirements and test results to enhance or change the performance of concrete. This part of the added substances is called admixture, plus The use of the agent should be strictly controlled, and the total amount required should be 5% by weight of the regional cement. Admixture quality, type selection, dosage and ratio have a significant impact on the quality and performance of concrete. In the actual construction process, concrete processing, addition and use of admixtures should be carried out in strict accordance with the relevant standards set by the State.
For all kinds of concrete admixtures, the role of the precipitant is mainly to reduce water consumption, increase the density and elasticity of the concrete, and make the concrete durable. The air entraining agent can improve the solubility of the concrete, and reduce the internal crack of the concrete by improving the internal structure of the concrete, so that the concrete can improve its antifreeze and impermeability. For concrete with higher frost resistance requirements, it is possible to properly perform bleed air or a mixture of precipitation additives. For concrete with higher impermeability requirements, the density of concrete must be increased by high-performance precipitants. At the same time, the air entraining additive is used to reduce the occurrence of water seepage and improve the impermeability of the building structure.
Concrete additive is an admixture added during concrete mixing. It is mainly used to improve the performance of concrete. From the point of addition ratio of admixture, generally not more than 5%.
For all kinds of concrete admixtures, the role of the precipitant is mainly to reduce the water consumption, increase the density and elasticity of the concrete, and make the concrete durable. The air entraining agent can improve the solubility of the concrete, and reduce the internal crack of the concrete by improving the internal structure of the concrete, so that the concrete can improve its antifreeze and impermeability. For concrete with high frost resistance requirements, it is possible to properly perform bleed air or a mixture of precipitation additives.
Concrete admixtures shall be selected carefully as per the specifications and shall be used as recommended by the manufacturer or by lab testing report. The quantity of admixtures to be used for specific application of admixtures are recommended by the manufacturers.
For use in large construction projects, the quantity of the admixture to be used shall be obtained from tests reports for concrete mixed with admixtures at various percentage admixtures use. These tests are conducted to understand the behaviour of admixtures on the desired quality and strength of concrete at different quantity of admixtures used. Thus, the optimum quantity of admixtures can be selected for specific application based on results.
Set retarding concrete admixtures are used to delay the chemical reaction that takes place when the concrete starts the setting process. These types of concrete admixtures are commonly used to reduce the effect of high temperatures that could produce a faster initial setting of concrete. Set retarding admixtures are used in concrete pavement construction, allowing more time for finishing concrete pavements, reducing additional costs to place a new concrete batch plant on the job site and helps eliminate cold joints in concrete. Retarders can also be used to resist cracking due to form deflection that can occur when horizontal slabs are placed in sections. Most retarders also function as water reducers and may entrain some air in concrete.