When the self-leveling mortar is not mixed with redispersible polymer powder, the expansion degree of 20min and 30min is 128mm and 112mm respectively, and the expansion loss is large over time, and the fluidity does not meet the requirements of not less than 130mm specified in JC T985-2005. In it is incorporated 0After 5% of the dispersible polymer powder, the expansion degree of the self-leveling mortar reaches 143mm after 30min, the expansion loss is small, and the fluidity is better: this is because the redispersible polymer powder can gather on the surface of hydrated and unhydrated products, reduce the internal friction of the mortar, and the surfactant contained in it introduces a large number of tiny bubbles into the new mortar to play the role of ball lubrication, thereby improving the fluidity of the mortar.
The redispersible polymer powder can reduce the time loss of the expansion of the mortar and prolong the working time of the mortar: when the content of the redispersible polymer powder exceeds 0After 5%, the fluidity of the self-leveling mortar fluctuates but does not change much. In addition, it was observed that the leveling self-healing property of the freshly mixed mortar became better with the increase of the dosage, and the cohesiveness gradually increased, when the content of latex powder reached 4At 0%, the cohesion of the mortar becomes so great that the workability decreases.
The affinity of redispersible polymer powder, especially to protect colloidal dispersion, to water and the subsequent viscosity improve the cohesion of the mortar, thereby improving the workability and self-healing of the mortar. However, under the condition that the water consumption remains unchanged, when the amount of latex powder is too much, the water absorption and thickening effect of latex powder is strong, which makes the cohesion of the new self-leveling mortar become very large, and the mortar becomes viscous, thereby reducing the workability, so the content of latex powder should not be too high. Hydroxypropyl methylcellulose ether manufacturer