The role of HPMC in wet mortar

Hydroxypropyl methylcellulose is used as a water retaining agent and retarder for cement mortar to make the mortar pumpable. In the plaster as a binder,so improve the spreadability and extend the operation time.

The water retention of hydroxypropyl methylcellulose HPMC enables the slurry to not crack too quickly after application, and enhances the strength after hardening.

Part I:

Water retention is an important property of hydroxypropyl methylcellulose HPMC. Factors affecting the water retention effect of the wet mix mortar include the amount of HPMC added, the viscosity of the HPMC, the fineness of the particles, and the temperature of the environment in which it is used.

The important role of hydroxypropyl methylcellulose in wet mortars is threefold:

First, excellent water retention capacity
The second is the effect on the consistency and thixotropy of wet mixed mortar.
The third is the interaction with cement.

The water retention effect of cellulose ether depends on the water absorption 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 condensed material.

The higher the transparency of hydroxypropyl methylcellulose, so the better the water retention. Factors affecting the water retention of wet mixed mortar.

Including cellulose ether viscosity, addition amount, particle fineness and use temperature. The greater the viscosity of the cellulose ether,so the better the water retention performance. Viscosity is an important parameter for HPMC performance.

Part II:

In general, the higher the viscosity, the better the water retention effect. However, the higher the viscosity, the higher the molecular weight of HPMC, and the lower the solubility. This has a negative impact on the strength and construction properties of the mortar.

The higher the viscosity, the more obvious the thickening effect on the mortar, but it is not proportional. The higher the viscosity, the more sticky the wet mortar will be. It is characterized by a sticky blade and high adhesion to the substrate during construction. However, the increase in the structural strength of the wet mortar itself is not helpful.

At the time of construction, the anti-sagging performance was not obvious. In contrast, some low-viscosity, but modified, hydroxypropyl methylcelluloses have excellent performance in improving the structural strength of wet mortars.

Part III:

The greater the amount of cellulose ether HPMC added in the wet mixed mortar,so the better the water retention performance, the higher the viscosity, the better the water retention performance.

In the wet mortar, the amount of cellulose ether HPMC added is very low. However, it can significantly improve the construction performance of wet mixed mortar, which is the main additive that affects the performance of mortar construction. Reasonable selection of the correct hydroxypropyl methylcellulose has a great impact on the performance of wet mixed mortar.