1. Cellulose ether has a certain retarding effect on mortar. As the dosage of cellulose ether increases, the setting time of the mortar is extended. The retarding effect of cellulose ether on cement slurry mainly depends on the degree of substitution of the alkyl group. The smaller the degree of substitution of the alkyl group and the greater the hydroxyl content, the more obvious the retarding effect. In addition, the higher the cellulose ether content, the more obvious the effect of the complex film on delaying the early hydration of the cementitious material, and therefore the more obvious the retardation effect, which affects the final strength of the mortar.

2. After the addition of hydroxypropyl methyl cellulose ether, the flexural strength of the mortar first increases and then decreases with the increase of the dosage, and the compressive strength gradually decreases.

3. Cellulose ether has a significant effect on the bonding properties of mortar. Cellulose ether forms a polymer film with a sealing effect between the cement hydration particles in the liquid phase system, which promotes the complete hydration of the cement because there is more water in the polymer film outside the cement particles. This improves the bond strength after the slurry hardens. At the same time, the right amount of cellulose ether enhances the plasticity and flexibility of the mortar, which reduces the rigidity of the interface transition zone between the mortar and the substrate and reduces the slip resistance between the interfaces. To a certain extent, it enhances the bonding effect between the mortar and the substrate. In addition, due to the presence of cellulose ether in the cement slurry, a special interface transition zone and interface layer are formed between the mortar particles and the hydration products. This interface layer makes the interface transition zone more flexible and less rigid, thus giving the mortar a stronger bond strength.