Ⅰ. The necessity of water retention
The water retention of mortar refers to the ability of mortar to retain water. Mortar with poor water retention is easy to bleed and segregate during transportation and storage, that is, water floats on the top, sand and cement sink below, and must be re-stirred before use.
All kinds of bases that require mortar for construction have a certain degree of water absorption. If the water retention of the mortar is poor, the ready-mixed mortar will be absorbed by the water as long as the ready-mixed mortar is in contact with the block or base during the application of the mortar. At the same time, the outer surface of the mortar evaporates water in the atmosphere, resulting in insufficient water in the mortar due to water loss, which affects the further hydration of the cement. At the same time, it affects the normal development of mortar strength, resulting in lower strength, especially the interface strength between the hardened mortar and the base layer, resulting in cracking and falling off of the mortar. For the mortar with good water retention, the cement hydration is relatively sufficient, the strength can be developed normally, and it can be better bonded to the base layer.
Ready-mixed mortar is usually built between water-absorbing blocks or spread on the base, forming a whole together with the base. The impact of poor water retention of mortar on project quality is as follows:
1. Due to the excessive loss of water from the mortar, it will affect the normal coagulation and hardening of the mortar, and reduce the bonding force between the mortar and the surface, which is not only inconvenient for construction operations, but also reduces the strength of the masonry, thereby greatly reducing the quality of the project.
2. If the mortar is not well bonded, the water is easily absorbed by the bricks, making the mortar too dry and thick, and the application is uneven. When the project is implemented, it not only affects the progress, but also makes the wall prone to cracking due to shrinkage. Therefore, increasing the water retention of mortar is not only beneficial to construction, but also increases the strength.