Dry-mix mortar (DMM) is a powdered building material formed by drying and crushing cement, gypsum, lime, etc. as the main base materials, after precise proportioning, adding a variety of functional additives and fillers. It has the advantages of simple mixing, convenient construction, and stable quality, and is widely used in construction engineering, decoration engineering and other fields. The main components of dry-mix mortar include base materials, fillers, admixtures and additives. Among them, cellulose ether, as an important additive, plays a key role in regulating rheology and improving construction performance.
1. Base material
The base material is the main component of dry-mix mortar, usually including cement, gypsum, lime, etc. The quality of the base material directly affects the strength, adhesion, durability and other properties of dry-mix mortar.
Cement: It is one of the most common base materials in dry-mix mortar, usually ordinary silicate cement or modified cement. The quality of cement determines the strength of the mortar. Common standard strength grades are 32.5, 42.5, etc.
Gypsum: commonly used in the production of plaster mortar and some special building mortar. It can produce better coagulation and hardening properties during the hydration process and improve the operability of the mortar.
Lime: generally used to prepare some special mortars, such as lime mortar. The use of lime can enhance the water retention of mortar and improve its frost resistance.
2. Filler
Filler refers to inorganic powder used to adjust the physical properties of mortar, usually including fine sand, quartz powder, expanded perlite, expanded ceramsite, etc. These fillers are usually obtained through a specific screening process with uniform particle size to ensure the construction performance of the mortar. The function of the filler is to provide the volume of the mortar and control its fluidity and adhesion.
Fine sand: commonly used in ordinary dry mortar, with a small particle size, usually below 0.5mm.
Quartz powder: high fineness, suitable for mortars that require higher strength and durability.
Expanded perlite/expanded ceramsite: commonly used in lightweight mortars, with good sound insulation and heat insulation properties.
3. Admixtures
Admixtures are chemical substances that improve the performance of dry-mix mortar, mainly including water-retaining agents, retarders, accelerators, antifreeze agents, etc. Admixtures can adjust the setting time, fluidity, water retention, etc. of mortar, and further improve the construction performance and application effect of mortar.
Water-retaining agent: used to improve the water retention of mortar and prevent water from volatilizing too quickly, thereby extending the construction time of mortar, which is of great significance, especially in high temperature or dry environment. Common water-retaining agents include polymers.
Retarders: can delay the setting time of mortar, suitable for high temperature construction environment to prevent mortar from hardening prematurely during construction.
Accelerators: accelerate the hardening process of mortar, especially in low temperature environment, often used to accelerate the hydration reaction of cement and improve the strength of mortar.
Antifreeze: used in low temperature environment to prevent mortar from losing strength due to freezing.
4. Additives
Additives refer to chemical or natural substances used to improve certain specific properties of dry-mix mortar, usually including cellulose ether, thickener, dispersant, etc. Cellulose ether, as a commonly used functional additive, plays a vital role in dry-mix mortar.
The role of cellulose ether
Cellulose ether is a class of polymer compounds made from cellulose through chemical modification, which are widely used in construction, coatings, daily chemicals and other fields. In dry-mix mortar, the role of cellulose ether is mainly reflected in the following aspects:
Improve the water retention of mortar
Cellulose ether can effectively increase the water retention of mortar and reduce the rapid evaporation of water. Its molecular structure contains hydrophilic groups, which can form a strong binding force with water molecules, thereby keeping the mortar moist and avoiding cracks or construction difficulties caused by rapid water loss.
Improve the rheology of mortar
Cellulose ether can adjust the fluidity and adhesion of mortar, making the mortar more uniform and easy to operate during construction. It increases the viscosity of mortar through thickening, increases its anti-segregation, prevents mortar from stratifying during use, and ensures the construction quality of mortar.
Enhance the adhesion of mortar
The film formed by cellulose ether in mortar has good adhesion, which helps to improve the bonding strength between mortar and substrate, especially in the construction process of coating and tiling, it can effectively improve the bonding performance and prevent falling off.
Improve crack resistance
The use of cellulose ether helps to improve the crack resistance of mortar, especially in the drying process, cellulose ether can reduce cracks caused by shrinkage by increasing the toughness and tensile strength of mortar.
Improve the construction performance of mortar
Cellulose ether can effectively adjust the construction time of mortar, prolong the open time, and enable it to maintain good construction performance in high temperature or dry environment. In addition, it can also improve the flatness and operability of mortar and improve the construction quality.
As an efficient and environmentally friendly building material, the rationality of its composition and proportion determines the quality of its performance. As an important additive, cellulose ether can improve the key properties of dry-mix mortar, such as water retention, rheology, and adhesion, and plays a vital role in improving the construction performance and quality of mortar. As the construction industry continues to increase its requirements for material performance, the application of cellulose ether and other functional additives in dry-mix mortar will become more and more extensive, providing greater space for the industry’s technological progress.
Post time: Apr-05-2025