Hydroxypropyl methyl cellulose (HPMC) is a commonly used additive in cement-based mortars to improve their dispersion resistance. When added to the mortar mix, HPMC forms a protective layer around the cement particles, which prevents them from sticking together and forming agglomerates. This results in a more uniform distribution of the cement particles throughout the mortar mix, which in turn improves its overall performance.
The dispersion resistance of cement-based mortars is important because it affects the workability and strength of the final product. When cement particles clump together, they create voids in the mortar mix, which can weaken the structure and reduce its durability. In addition, clumping can make the mortar more difficult to work with, which can lead to issues during construction.
HPMC addresses these issues by improving the flow and workability of the mortar mix. By forming a protective layer around the cement particles, HPMC reduces the amount of water needed to achieve a workable consistency, which in turn reduces the risk of segregation and bleeding. This results in a more homogenous and cohesive mixture, which is easier to apply and finish.
Overall, the addition of HPMC to cement-based mortars can improve their performance by enhancing their dispersion resistance, workability, and durability.