What is the water-retaining and thickening material?
The water-retaining and thickening material refers to a type of non-lime materials used in mortar to improve the operability of mortar and to enhance the ability of mortar to retain moisture. The water-retaining and thickening material should have the ability to retain moisture first. Another role is to improve the operability of mortar, which is related to but different from improving water retention. The thickening effect is mainly to improve the stickiness, lubricity, spreadability, thixotropy and etc., of mortar so that mortar has the ability to be easily deformed under external force and to maintain no deformation after the external force disappears. Mortar requires a certain adhesion for the substrate, but the adhesion should not be very high.
Whether it is cement-based or gypsum-based mortar, its inorganic cementitious materials both require a certain amount of water, in order to ensure that cementitious materials get hydrated to form hydration products. If the water in the mortar cannot fully guarantee the hydration of inorganic cementitious materials, then both the bond strength and compressive strength of mortar will be reduced, so the adhesive force of masonry mortar and block materials gets poor, and plastering mortar is easy for shelling and cracking.