Application of HPMC in Self-compacting Concrete
November 27th 2024
Talking about the application of hydroxypropyl methylcellulose in putty powder
Today, we will lead you to understand the role of hydroxypropyl methylcellulose in putty powder. Generally speaking, it has three functions: thickening, water retention and construction.
Thickening: Cellulose can be thickened to suspend, keep the solution uniform and consistent, and resist sagging.
Water retention: Make the putty powder dry slowly, and assist the reaction of ash calcium under the action of water.
Construction: Cellulose has a lubricating effect, which can make the putty powder have good workability.
Hydroxypropyl methylcellulose HPMC does not participate in any chemical reaction and only plays an auxiliary role. Adding water to the putty powder and putting it on the wall is a chemical reaction. Because of the formation of new substances, take the putty powder on the wall off the wall, grind it into powder, and use it again. It will not work, because new substances (calcium carbonate) have been formed. ) up. The main components of ash calcium powder are: a mixture of Ca(OH)2, CaO and a small amount of CaCO3, CaO+H2O=Ca(OH)2—Ca(OH)2+CO2=CaCO3↓+H2O Ash calcium in water and air Under the action of CO2, calcium carbonate is generated, while HPMC only retains water and assists the better reaction of ash calcium, and does not participate in any reaction itself.
Putty powder is generally 100,000, and the mortar is more demanding, and it is easy to use at 150,000. Moreover, the most important role of hydroxypropyl methylcellulose HPMC is to retain water, followed by thickening. In putty powder, as long as the water retention is good and the viscosity is lower (70,000-80,000), it is also possible. Of course, the viscosity is higher, and the relative water retention is better. When the viscosity exceeds 100,000, the effect of viscosity on water retention is Not much.
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