Hydroxypropyl methylcellulose (HPMC), as a water-soluble polymer compound, is widely used in the improvement of cement-based materials. As an important additive, it can significantly improve the physical and chemical properties of cement-based materials, especially in terms of operability, fluidity, adhesion and durability of reinforcing materials.

1. Improve the fluidity of cement-based materials
Cement paste needs good fluidity during construction so that it can be smoothly poured into the mold and fill complex shapes. After adding hydroxypropyl methylcellulose, the cement paste can maintain good fluidity due to its excellent thickening effect. During use, HPMC can improve the fluidity by changing the viscosity of the paste, so that the paste has a longer working time and is not prone to segregation, which is convenient for construction personnel to operate the material.

2. Improve the adhesion of cement-based materials
The adhesion of cement-based materials is crucial to its durability and strength improvement. HPMC is a water-soluble polymer compound with a large number of hydrophilic groups in its molecular structure, which enables it to interact strongly with cement particles and other fillers to form a stable network structure. This effect can not only improve the bonding performance between cement and substrate, but also enhance the crack resistance and peeling resistance of cement-based materials and improve their durability. Studies have shown that cement-based materials with the addition of HPMC can effectively reduce cracking, peeling and debonding, thereby increasing the service life of the material.

3. Improve the impermeability of cement-based materials
The impermeability of cement-based materials is one of the important indicators affecting their durability. The introduction of HPMC can improve the microstructure of cement-based materials, forming a dense network structure, thereby reducing the porosity in the cement paste. The reduction in porosity directly improves the impermeability of cement-based materials. Studies have shown that adding an appropriate amount of HPMC can effectively prevent cement-based materials from being eroded by water during long-term use, reduce their water permeability, and thus improve the waterproof performance of buildings.

4. Delaying the hydration process of cement
The hydration process of cement is a complex chemical reaction process. In the production and construction of cement-based materials, the rate of hydration reaction has a direct impact on the final performance. The addition of HPMC can delay the hydration process of cement by changing the viscosity of cement paste. HPMC can effectively extend the working time and prevent the cement paste from solidifying too quickly. This feature is particularly suitable for cement-based materials that require long-term operation, which can improve the flexibility of construction and the operability of materials.

5. Improving the freeze-thaw resistance of cement-based materials
In cold areas, cement-based materials are often exposed to freeze-thaw cycles, which can lead to a decrease in the strength of the materials and structural damage. The addition of HPMC to cement-based materials helps to improve their freeze-thaw resistance. By reducing the porosity in cement-based materials, HPMC can effectively reduce the expansion pressure of water when it freezes in cement-based materials, thereby improving the freeze-thaw resistance of the materials. Studies have shown that when the amount of HPMC added is appropriate, the freeze-thaw resistance of cement-based materials is significantly improved, especially in buildings in humid and cold areas.

6. Enhance the high temperature resistance of cement-based materials
When cement-based materials are used in high temperature environments, they often face problems such as thermal expansion and contraction, and decreased physical properties. The addition of HPMC can improve the high temperature resistance of cement-based materials. Since HPMC has good thermal stability, it can maintain its chemical structure and physical properties at high temperatures, thereby enhancing the strength and durability of cement-based materials in high temperature environments.

7. Improve construction performance
Construction performance is one of the important criteria for measuring the quality of cement-based materials. HPMC can significantly improve the operability of cement-based materials and prevent problems such as segregation and water seepage during construction. When applying, plastering or pouring cement-based materials, the introduction of HPMC makes the material have better plasticity and longer open time, so that construction workers can adjust and trim more conveniently, reducing problems caused by uneven distribution of materials during construction.

As an important additive for cement-based materials, hydroxypropyl methylcellulose can significantly improve the various properties of materials. HPMC shows excellent performance in the application of cement-based materials by improving fluidity, adhesion, impermeability, freeze-thaw resistance and delaying cement hydration process, especially in improving construction performance and durability. Therefore, in modern construction projects, the use of hydroxypropyl methylcellulose has broad prospects and plays a positive role in improving the comprehensive performance of building materials.