What effect does defoaming agent have on the performance of gypsum self-leveling mortar?
Defoaming agents are generally only used in model gypsum, precision casting gypsum, self-leveling gypsum mortar, etc. to reduce pores on the surface of gypsum products. Commonly used defoaming agents include n-butanol, polyethylene glycol, tributyl phosphate and other organic substances.
During construction, when dry powder is mixed with water, bubbles are often generated, which affects the aesthetics of the product. Adding an appropriate amount of dry powder defoamer can effectively eliminate bubbles and pinholes in dry powder mortar products, and eliminate pores and cavities produced during scraping and spraying. It can also improve the anti-permeability performance and increase the strength of the product.
The general dosage of dry powder defoamer is between 0.2% and 0.5%.
The mortar contains an appropriate amount of closed and stable small bubbles evenly distributed, which will greatly improve the freeze-thaw resistance, abrasion resistance, durability and drying shrinkage resistance of the mortar. However, uneven or unstable bubbles will not only cause self-leveling The rough surface of the mortar will also greatly affect its strength and other properties. Selecting an appropriate defoaming agent can accelerate the collapse and elimination of unstable large bubbles, make the bubbles uniform, and improve the performance of the mortar. This is because the defoaming agent is also a surfactant. It can not only eliminate bubbles in the mortar, but also act as a foam stabilizer to stabilize the bubbles. The dosage of this kind of defoaming agent is 0.5%.
Adding a defoaming agent to the gypsum-based self-leveling mortar system can increase the fluidity of the self-leveling mortar, improve the apparent state of the mortar after hardening, and increase the wet density of the mortar, thereby improving the pressure resistance and strength of the self-leveling mortar after hardening. The flexural strength has been significantly improved.
The powder defoamer currently used in mortar products is mainly imported compound defoamer. The suitability of different brands of defoamer in the same mortar product is different, resulting in differences in the performance of the mortar product. Choosing a suitable defoamer for mortar products that require defoaming will greatly help improve the overall performance of the mortar.
