The important role of HPMC in wet-mixed mortar

The important role of HPMC in wet-mixed mortar mainly has the following three aspects:

1. HPMC has excellent water retention capacity.

2. The influence of HPMC on the consistency and thixotropy of wet-mixed mortar.

3. The interaction between HPMC and cement.

Water retention is an important performance of HPMC, and it is also a performance that many wet-mix mortar manufacturers pay attention to.

The water retention effect of HPMC depends on the water absorption rate of the base layer, the composition of the mortar, the layer thickness of the mortar, the water demand of the mortar, and the setting time of the setting material.

HPMC – water retention

The higher the gel temperature of HPMC, the better the water retention.

The factors affecting the water retention of wet-mixed mortar are HPMC viscosity, addition amount, particle fineness and use temperature.

Viscosity is an important parameter for HPMC performance. For the same product, the viscosity results measured by different methods vary greatly, and some even double the difference. Therefore, when comparing viscosities, it needs to be done between the same test methods, including temperature, spindle, etc. Generally speaking, the higher the viscosity, the better the water retention effect.

However, the higher the viscosity and the larger the molecular weight of HPMC, the corresponding decrease in its solubility will have a negative impact on the strength and construction performance of the mortar. The higher the viscosity, the more obvious the thickening effect of the mortar, but not proportional. The higher the viscosity, the more viscous the wet mortar is, which shows stickiness to the scraper during construction and high adhesion to the substrate. However, HPMC has little effect on improving the structural strength of the wet mortar itself, indicating that the anti-sagging performance is not obvious. On the contrary, some modified HPMC with medium and low viscosity are excellent in improving the structural strength of wet mortar.

The fineness of HPMC also has a certain influence on its water retention. Generally speaking, for HPMC with the same viscosity but different fineness, the finer the HPMC, the better the water retention effect under the same addition amount.