my country's current "Technical Regulations on the Application of Concrete Admixtures" does not include pumping agents, but the application scope of pumping agents is becoming more and more extensive, especially in the commercial concrete industry and many other industries. In large-scale construction projects, pumping agents can be said to be the main admixtures. In 1992, my country promulgated the "Concrete Pumping Agent" industry standard (JC473-92). Nine years ago, the new standard (JC473-2001) has been compiled. This shows that the production and application of pumping agents have been very mature. The following Let’s talk about some opinions on the application technology of pumping agent.
Pumping agent is mainly used for pumping concrete. The main technical characteristics of pumped concrete are three points: good workability; excellent fluidity ( Diffusion); longer plastic retention time. To meet the requirements of these three technical indicators, in addition to the technical factors of mix ratio design, it largely depends on the quality of the pumping agent. That is to say, the main technological index requirement for pumping concrete is to verify the quality of the pumping agent. This means that the requirements for the main process indicators of pumped concrete are the key to verifying the quality indicators of the pumping agent. Concrete has good workability and does not produce slurry, so that the slurry and the stone can be integrated seamlessly. Its antagonist is bleed. Good fluidity enables concrete to be pumped freely, and its opposite factor is a small increase in slump. Only with a long plastic retention time can the concrete have enough transportation time and pouring time. The opposite factor is that the slump retention value is small. Therefore, when we verify or select pumping agents, we must focus on the three indicators of bleeding rate ratio, slump increase value, and slump retention value on the basis that other technical indicators meet the requirements of (JC473-2001) , the higher the indicator quality, the better.
Generally, pumping agents use high-efficiency water-reducing admixture as the main masterbatch, with a small amount of air-entraining agent added to change the workability, and some retarders added. Agent or polymer plastic retaining agent to reduce slump loss value. Judging from the composition and properties of its formula materials, its application technical precautions should refer to the two products of retarding high-efficiency water reducing agent and air-entraining agent. It is particularly important to emphasize that when encountering hot-ground cement or cement containing anhydrite, pumping agents containing sugar or calcium lignin must not be used, otherwise excessive slump loss or even rapid solidification will occur.
In short, due to the wide variety of admixtures and different engineering and technical requirements, admixtures must be used correctly and reasonably; first, we must be familiar with the various admixtures currently available in the country standards; the second is to be familiar with the current national engineering standards. The former is to understand the performance of the product, and the latter is to know your own needs. Both are indispensable. The general principles for applying admixtures are: first, to meet technical needs; second, to achieve economic benefits, and it is best to achieve both. </p
微信扫一扫打赏
