The importance of HPMC in retaining water from mortar

First, the necessity of water retention

Water retention of mortar

It refers to the ability of mortar to retain moisture and water retention. It is easy to be separated from water during transportation and storage. That is, water floats on top, sand and cement sink below, and must be stirred again before use.

All kinds of base layers that require mortar construction have a certain water absorption.

If the mortar has poor water retention, during the application of the mortar, as long as the ready-mixed mortar is in contact with the block or the base layer, the ready-mixed mortar is suck away.

At the same time, the outer surface of the mortar evaporates water into the atmosphere, causing the water to be dehydrat due to water loss, which affects the further hydration of the cement.

At the same time, it affects the normal development of the mortar strength, resulting in the strength, especially the interface strength between the hardened body of the mortar and the base layer becomes low, causing the mortar to crack and fall off.

The mortar with good water retention has sufficient hydration of the cement. The strength can be normalize and the base layer can be well bond.

The ready-mixed mortar is usually laid between the water-absorbing blocks or apply to the base layer to form a whole with the base. The poor water retention capacity of the mortar has an impact on the quality of the project:

1.

Because the mortar loses too much water, it affects the normal coagulation and hardening of the mortar, and reduces the adhesion between the mortar and the surface.

Not only is it inconvenient for the construction operation, but also the strength of the masonry is lower, so that the quality of the project is greatly reduce.

2.

If the mortar is poorly bond, the water is easily suck by the bricks, making the mortar too thick and smeared.

When the project was implement, it not only affect the progress. But also cause the wall surface to be crack due to shrinkage.

Therefore, increasing the water retention of the mortar is not only advantageous for construction, but also increases the strength.

Second, the traditional water retention method

The traditional solution is to water the base layer.But this does not guarantee that the base layer will be evenly moistened.

The ideal hydration target of cement mortar on the base layer is that the cement hydration product penetrates into the base layer along with the process of absorbing water from the base layer to form an effective “key joint” with the base layer to achieve the required bond strength.

Watering directly to the surface of the base layer will cause the water absorption of the base layer to be seriously disperse due to differences in temperature, watering time, and watering uniformity.

The base layer absorbs less water and will continue to absorb the moisture in the mortar. The water is suck away before the cement hydrates.

It affects the penetration of cement hydration and hydration products into the matrix; the water absorption of the base layer is large. And the migration of water in the mortar to the base layer is slow.

Even a water-rich layer is form between the mortar and the matrix, which also affects the bond strength.

Therefore, the common base watering method can not effectively solve the problem of high water absorption of the base layer of the wall. But will affect the bonding strength between the mortar and the base layer, resulting in empty drums and dry cracks.

Third, the role of efficient water retention

HPMC’s water retention performance has several advantages:

1.HPMC’s excellent water retention performance makes the mortar open longer. And has the advantages of large-area construction, long-term use in the barrel, batch mixing and batch use.

2.The water retention of HPMC can make the cement in the mortar hydrated sufficiently. And effectively improve the bonding performance of the mortar.

3.HPMC’s excellent water retention can make the mortar less prone to segregation and bleeding. So that the workability and workability of the mortar are improve.