The water holding capacity of cement mortar is affected by cellulose ether

Shandong chuangyao Biotechnology Co., Ltd. specializes in the production of hydroxypropyl methyl cellulose and redispersible latex powder products. In the construction, the role and performance of cement mortar is relatively strong, and its water retention capacity is affected by cellulose ether. The following is a brief analysis by Shandong chuangyao Biological Technology Co., Ltd

The base course of mortar construction has a certain degree of water absorption. After the base absorbs the water in the mortar, the workability of the mortar will become worse. In serious cases, the cementitious materials in the mortar can not be fully hydrated, resulting in the strength, especially the interface strength between the hardened mortar and the base, which will cause mortar cracking and falling off. The traditional way to solve these problems is to water the base, but it is impossible to ensure that the base is evenly and moderately moist.

The ideal hydration target of cement mortar on the base course is that the hydration products of cement infiltrate into the base course along with the water absorption process of the base course, forming an effective "key connection" with the base, so as to achieve the required bond strength. Direct watering to the surface of the base course will cause serious dispersion of water absorption due to different temperature, watering time and watering uniformity. If the water absorption of the base is small, it will continue to absorb the water in the mortar. Before the cement hydration, the water will be absorbed, which will affect the cement hydration and hydration products' penetration into the matrix; if the water absorption capacity of the base course is large, the water content in the mortar will migrate slowly to the base course, and even form a rich layer between the mortar and the matrix, which will also affect the bond strength. Therefore, the common base watering method can not effectively solve the problem of high water absorption of wall base, but will affect the bond strength between mortar and base, resulting in hollowing and dry cracking.

The influence of HPMC on the compressive and shear strength of cement mortar.

With the addition of hydroxypropyl methyl cellulose ether, the compressive strength and shear strength decreased, because the cellulose ether absorbed water and increased the porosity.

The bond performance and bond strength depend on whether the interface between mortar and substrate can realize "key connection" stably and effectively for a long time.

The influence of bond strength mainly includes three aspects

First: the water retention capacity, permeability and structural strength of mortar.

Second, the water absorption characteristics and roughness of the substrate interface.

Third: construction tools, construction methods, construction environment.

Therefore, when determining the target bond strength index and batching technology between mortar and substrate, the above factors should be fully considered to select cementing materials, aggregates, aggregates, water retaining agent, binder, construction performance regulator, etc. For example, gypsum based mortar has better bonding performance than cement-based mortar in dry state, but its binder performance decreases rapidly under the condition of moisture absorption and water absorption. The target bond strength of plastering mortar should be reduced layer by layer, that is, the bond strength between base layer and interface treatment agent is greater than that between bottom layer mortar and interface treatment agent, that is, the bonding strength between bottom layer mortar and surface layer mortar is greater than that between surface mortar and putty material.

For technical issues related to cellulose and other products, please visit the company's official website: www.cyhuagong.com