What are the specific requirements for the performance of premixed mortar water retaining agent?
Publish Time: 2024-08-21
The performance requirements of premixed mortar water retaining agent are mainly as follows:
Water retention:
High water retention rate: The water retaining agent should be able to significantly improve the water retention capacity of the mortar, so that the mortar maintains a high moisture content within the specified time. For example, for ordinary masonry mortar, the water retention rate is generally required to be no less than 88%; for plastering mortar, the water retention rate may be required to be higher, usually above 92%, to ensure that the cement has enough time for hydration reaction, to ensure the strength development and bonding performance of the mortar, and to reduce the problems of mortar cracking and hollowing caused by excessive loss of water.
Moisture stability: Under different environmental conditions (such as temperature and humidity changes) and during construction, the water retaining agent can stably maintain the moisture in the mortar, and will not cause a large amount of water loss or water seepage due to external factors, so as to maintain the stability of the workability and construction quality of the mortar.
Adhesion:
Enhance the bonding strength: It can effectively improve the bonding force between the mortar and the base layer and the components inside the mortar, so that the mortar can better adhere to the surface of the base layer and avoid hollowing and falling off. For example, in the tile bonding mortar, adding a suitable water-retaining agent can greatly improve the bonding strength and ensure the firmness of the tile pasting.
Good bonding durability: not only should there be sufficient bonding strength at the beginning of construction, but also good bonding performance can be maintained for a long time after the mortar hardens, ensuring that the bonding between the mortar layer and the base or other structural layers is firm and reliable during the long-term use of the building.
Workability:
Improve fluidity: Make the mortar have appropriate fluidity during mixing, transportation and construction, easy to apply, spread and pour, improve construction efficiency, and ensure that the mortar is evenly filled in various parts to avoid local lack of mortar or looseness.
Reduce segregation and water seepage: Prevent the separation of aggregates and cement slurry and other components in the mortar, and prevent water from precipitating from the mortar to the surface, ensure the overall uniformity and stability of the mortar, and thus obtain a flat and smooth construction surface.
Slow setting:
Appropriate slow setting effect: In some cases (such as high temperature environment or large-scale construction), the water retainer should be able to appropriately extend the setting time of the mortar, give the construction workers enough operating time, ensure that the mortar maintains good plasticity and operability during the construction process, and avoid affecting the construction quality and progress due to premature setting of the mortar. However, the slow setting time should not be too long, so as not to affect the final strength development of the mortar and the delivery time of the project.
Crack resistance:
Inhibit crack generation: By improving the flexibility and deformation resistance of the mortar, reduce the possibility of cracks in the mortar under the action of factors such as drying shrinkage, temperature changes, and base deformation. For example, in some premixed mortars used in some areas prone to cracks (such as wall corners, board joints, etc.), the crack resistance of the water retainer is particularly important.
Enhance impermeability: Good crack resistance helps to improve the impermeability of the mortar, prevent moisture from penetrating into the building through cracks, avoid adverse effects on the structure and durability of the building, and reduce the risk of building leakage.
Compatibility:
Compatibility with other materials: It has good compatibility with other components such as cement, aggregates, admixtures, etc. in premixed mortar, and will not cause chemical reactions or physical effects that will lead to a decrease in mortar performance or abnormal phenomena. For example, the water retainer should have good adaptability to cement, and the interaction between the two should not affect the hydration process of cement or change the basic properties of mortar.
Adaptability to construction technology: It can adapt to different construction processes and equipment requirements, such as manual application, mechanical spraying, etc., and can play its role in water retention and viscosity increase under various construction conditions to ensure the smooth progress of construction and the stability of mortar quality.
Environmental protection:
Non-toxic and harmless: The water retainer itself should be non-toxic, odorless, non-irritating, and will not cause harm to human health and the environment, and meet the relevant national environmental protection standards and requirements.
Degradability: During long-term use, the water retainer should be able to gradually degrade in the natural environment or under specific conditions, and will not cause long-term pollution and damage to soil, water sources, etc.
