TOP 3 Effects of HPMC on the Performance of Wet-mix Mortar

HPMC significantly enhances the performance of wet-mix mortar. Wet-mix mortar comprises a blend of cement, fine aggregate, mineral admixtures, additives, and water in specific proportions. After being measured and mixed at a mixing station, it is transported to the designated area and utilized within a defined timeframe. The raw materials used in wet-mix mortar don’t require drying, eliminating the need for on-site storage tanks, mixers, and related equipment. It boasts advantages such as cost-effectiveness, centralized mixing, consistent quality, and eco-friendly manufacturing.

In the current construction landscape where manual operations still prevail, the quantity of wet-mix mortar supplied at once must exceed the immediate construction needs. This necessity dictates that wet-mix mortar must maintain good water retention and consistency over an extended period. As a result, the water retention rate and setting time of the wet-mix mortar mixture have become crucial technical indicators governing its widespread adoption and use.

1.HPMC can improve the cohesion and water retention of the wet mortar mixture, but excessive mixing will reduce the consistency of the wet mortar mixture.

Water retention rate is an important performance index of wet-mixed mortar. While some components of mortar and concrete are the same, they function differently. Typically, concrete is poured into concrete and wooden formwork that retains a significant amount of water. Mortar, however, is commonly applied onto surfaces that absorb water, leading to quicker moisture loss or evaporation into the atmosphere. Consequently, maintaining water retention in mortar becomes more critical compared to concrete.

HPMC contributes to the consistency of wet-mix mortar primarily through its water-retaining properties. It enhances mortar cohesion, reduces the rate of mortar bleeding to a certain extent, and within a specific dosage range, improves the fluidity of wet-mix mortar. However, a high concentration of Hydroxypropyl Methylcellulose can excessively increase mortar cohesion, diminishing its fluidity and complicating the construction process.

2. HPMC tends to decrease the compressive strength of wet-mix mortar specimens, and this reduction is notably more pronounced. However, HPMC has the capability to enhance the tensile bonding strength of wet-mixed mortar.

For plastering mortar, bonding strength holds significant importance. In general, plastering mortar demands excellent workability to form a uniform layer on construction surfaces. Strong bonding between the mortar and the base layer ensures long-term durability, preventing cracking and detachment.

Cellulose ether, in conjunction with hydration particles, creates a thin polymer film that acts as a sealant, curbing water loss and ensuring sufficient moisture for cement hydration and strength development. This process improves paste bonding strength. Additionally, Hydroxypropyl Methylcellulose augments the cohesiveness of wet-mix mortar, ensuring good plasticity and flexibility, reducing stress at the interface between the mortar and substrate, thereby enhancing the mortar’s bonding capability.

3. It’s suggested to mix HPMC into the wet-mix mortar as a solution rather than directly incorporating it in powdered form during the preparation process.

Using HPMC in solution form yields superior results in enhancing water retention, cohesion, and mechanical properties of wet-mix mortar. When the concentration of Hydroxypropyl Methylcellulose ranges from 0.01% to 0.04%, the water retention rate of HPMC in solution form surpasses that of powdered HPMC in wet-mix mortar by 1.4% to 3.0%. Hence, employing HPMC in solution form proves more effective in improving the water retention of wet-mix mortar.


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