The anionic surfactant contained in construction additives can make the cement particles disperse each other so that the free water encapsulated by the cement aggregate is released, and the agglomerated cement aggregate is fully diffused and thoroughly hydrated to achieve a dense structure and increase the mortar strength, improve impermeability, crack resistance and durability.
The mortar mixed with additives has good workability, high water retention rate, strong adhesion, non-toxic, harmless, safe and environmentally friendly. It is suitable for the production of ordinary masonry, plastering, ground and waterproof mortar in ready-mixed mortar factories, and is used in the construction of concrete clay bricks, ceramsite bricks, hollow bricks, concrete blocks, and non-burning bricks in various industrial and civil buildings. Construction of interior and exterior wall plastering, concrete simple wall plastering, ground, roof leveling, waterproof mortar, etc.
1. Cellulose ether
In ready-mixed mortar, cellulose ether is a main additive that is added at a very low level, but can significantly improve the properties of wet mortar and affect the construction properties of mortar. Reasonable selection of cellulose ethers of different varieties, different viscosities, different particle sizes, different viscosity degrees and addition amounts will have a positive impact on the improvement of the performance of dry mortar.
In the production of building materials, especially dry mortar, cellulose ether plays an irreplaceable role, especially in the production of special mortar (modified mortar), it is an indispensable and important part. Cellulose ether plays the role of water retention, thickening, delaying cement hydration power, and improving construction performance. Good water retention capacity makes cement hydration more complete, which can improve the wet viscosity of wet mortar, improve the bond strength of mortar, and can adjust operation time. The addition of cellulose ethers to mechanical spray mortars can improve the spraying or pumping properties of the mortar, as well as the structural strength. Therefore, cellulose ether is being widely used as an important additive in ready-mixed mortar.
2. Redispersible polymer powder
Redispersible latex powder is a powdery thermoplastic resin obtained by spray drying and subsequent processing of polymer emulsion. It is mainly used in construction, especially dry powder mortar to increase cohesion, cohesion and flexibility.
The role of redispersible latex powder in mortar: after dispersion of redispersible polymer powder, it forms a film and acts as a second adhesive to enhance adhesion; the protective colloid is absorbed by the mortar system and will not be destroyed by water after film formation or second dispersion; the film-forming polymer resin is distributed throughout the mortar system as a reinforcing material, thereby increasing the cohesion of the mortar.
In wet mortar, dispersible polymer powder can improve construction performance, improve flow performance, increase thixotropy and sag resistance, improve cohesion, prolong opening time, and enhance water retention. After the mortar is cured, it can improve tensile strength. Tensile strength, enhanced flexural strength, decreased elastic modulus, increased deformability, increased material density, increased wear resistance, increased cohesive strength, decreased carbonization depth, decreased material water absorption, and made the material extremely property of hydrophobic and so on.
3. Air entraining agent
Air-entraining agent, also known as aerating agentt, refers to the introduction of a large number of evenly distributed tiny air bubbles in the process of mortar mixing, which can reduce the surface tension of the water in the mortar, resulting in better dispersibility and reducing the mortar mixture. Additives for bleeding and segregation. In addition, the introduction of fine and stable air bubbles also improves workability. The amount of air introduced depends on the type of mortar and the mixing equipment used.
Although the amount of air-entraining agent is very small, the air-entraining agent has a great influence on the performance of ready-mixed mortar. It can effectively improve the workability of ready-mixed mortar, improve the impermeability and frost resistance of mortar, and reduce the density of mortar. , save materials and increase the construction area, but the addition of air-entraining agent will reduce the strength of the mortar, especially the pressure-resistant mortar. Therefore, the amount of air-entraining agent should be strictly controlled, and the air content of the mortar, construction performance and The relative strength to determine the optimal amount of addition.
4. Early strength agent
The early strength agent is an additive that can accelerate the development of the early strength of mortar. Most of them are inorganic electrolytes, and a few are organic compounds.
The early strength agent for ready-mixed mortar is required to be powder and dry. Calcium formate is the most widely used in ready-mixed mortar. Calcium formate can improve the early strength of mortar and accelerate the hydration of tricalcium silicate, which has a certain water-reducing effect, and the physical properties of calcium formate are stable at room temperature. It is not easy to agglomerate, and it is more suitable for application in dry powder mortar.
5. Water reducing agent
Water reducing agent refers to an additive that can reduce the amount of mixing water under the condition that the consistency of the mortar is basically the same. Superplasticizers are generally surfactants, which can be divided into: ordinary superplasticizers, superplasticizers, early-strength superplasticizers, retarding superplasticizers, retarding superplasticizers, and superplasticizers according to their functions.
The water reducing agent used for ready-mixed mortar is required to be powdery and dry. Such a water-reducing agent can be uniformly dispersed in the dry powder mortar without reducing the shelf life of the ready-mixed mortar. At present, the application of water reducing agent in ready-mixed mortar is generally in cement self-leveling, gypsum self-leveling, batch scraping mortar, waterproof mortar, putty, etc. The selection of water reducing agent depends on different raw materials and different mortar properties. optional.
Ready-mixed mortar additives also include retarders, accelerators, fibers, thixotropic lubricants, defoaming agents, etc., which are added according to different types of mortars. These additives are used in ready-mixed mortar to bring about improvement in performance which is like the seasoning of cooking food. It is added to the dishes to brighten the color of the dishes, increase the taste, and lock the nutrition, so that different types of ready-mixed mortars can play a better role. A magic weapon for better use in dry mixed mortar projects.
Post time: Aug-11-2023