What is water retention of mortar?

Water retention refers to the ability of mortar to retain water. Water retention of poor mortar, the use of the process of water secretion, slurry, so that the mortar and the substrate bonding is not firm, and due to the loss of water affects the normal bonding of mortar hardening, so that the strength of the mortar is reduced.

The main factors affecting the water retention of mortar are the type and amount of cementitious materials, sand varieties, fineness and water consumption. In the mortar mixed with lime paste, fly ash and other powdery mixed materials, can improve the water retention of mortar.

Extended information:

p>Necessity of water retention: All kinds of grassroots that require mortar for construction have a certain degree of water absorption. After the grass-roots level absorbs the water in the mortar, it will make the construction of the mortar worse, and in serious cases, the cementitious materials in the mortar can not be fully hydrated, resulting in strength, especially the interface between the hardened mortar and the grass-roots level, resulting in cracking and peeling of the mortar.

If the plastering mortar has appropriate water retention properties, it can effectively improve the constructability of the mortar, but also make the water in the mortar is not easy to be absorbed by the grass-roots level, to ensure that the cement is fully hydrated. In addition, the traditional water retention method of the problem:

The traditional solution is to pour water on the grass-roots level, but this is not possible to ensure that the grass-roots level is uniformly and appropriately wet. The ideal hydration goal of cement mortar on the grass-roots level is that the hydration products of cement will penetrate into the grass-roots level along with the process of absorbing water by the grass-roots level, and form an effective "key-link" with the grass-roots level, so as to achieve the required bonding strength.

Pouring water directly to the surface of the grass-roots level will cause the water absorption of the grass-roots level to be seriously dispersed due to the difference in temperature, watering time and watering uniformity. Grass-roots water absorption is small, will continue to absorb water in the mortar, before the cement hydration, water is sucked away, affecting the cement hydration and hydration products to the substrate penetration;

Grass-roots water absorption is large, water in the mortar to the grass-roots level in the slow migration speed, and even in the mortar and the substrate to form a water-rich layer between the same impact on the bonding strength. So with the common grass-roots watering method, not only can not effectively solve the problem of high water absorption of the wall grass-roots level, but also affect the bond strength of mortar and grass-roots level, resulting in hollow drums, dry cracks.

Baidu Encyclopedia-Mortar