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Why You Should Add Hydroxypropyl Methylcellulose to The Mortar?

HPMC is an additive widely used in construction mixes to ensure superior quality and structural integrity. The addition of HPMC makes any mortar smoother and more uniform, which makes the construction process quicker and easier. In this blog, we will examine why HPMC is important as a construction additive and the diversity of its applications.

Understanding HPMC Composition

HPMC (Hydroxypropyl methylcellulose) is classified as a non-ionic cellulose ether. Its physical appearance is like a white powder. It has no odor or taste and is not toxic. It is not very reactive and does not react with heavy metals. HPMC for mortar is available in different types that differ from each other based on methoxyl content, hydroxyl content, and viscosity.

Why HPMC is Added to Mortar?

1.   Enhanced Water Retention

The specialty of HPMC is that it absorbs water. Adding this to any kind of mortar, whether it is masonry mortar, plaster, or ground-leveling mortar, improves the workability of the mortar. The mortar becomes softer and smoother so it can be spread evenly.

2.   Thickens the Consistency

Once HPMC is added, the consistency of the mortar thickens, making it easier to mold and achieve a specific appearance. Moreover, it also boosts the volume and makes the mortar look solid.

3.   Has a Retarding Effect

Adding HPMC delays the setting time of the mix. This gives the mason more time to place the mortar correctly or mold it as the design plan requires. HPMC makes the mortar flexible.

4.   Makes Mortar Crack-Resistant

Once HPMC is mixed with the mortar, it expands and contracts without cracking. This allows the mortar to withstand temperature fluctuations in the environment and makes it crack-proof.

5.   Increases Durability

HPMC also makes the mortar or plaster water—and corrosion-resistant, which makes the mortar last longer and reduces the need for renovation. When mixed, HPMC also produces air bubbles, which enhance the mortar's frost resistance.

Applications of HPMC in Dry Mix Mortars

1.   Plastering Mortar

Including HPMC in plastering mortar boosts water retention, which hydrates the cement. The hydrated cement forms a stronger bond and has a higher tensile strength.

2.   Wall Putty

HPMC is another useful additive in wall putty. It makes the putty crack-proof and prevents it from getting dehydrated, which makes it more robust and makes the putty stick better to the surface. It also eliminates the problem of sagging in construction.

3.   Gypsum Plaster

In gypsum-based plasters, HPMC is vital for increasing lubrication and water retention, which delays the setting time. This allows for better workability, leading to a more stable and durable final result.

4.   Tile Adhesive

In tile adhesive, HPMC prevents moisture absorption by the substrate and tiles. This traps moisture for a prolonged period, improving adhesiveness. It also makes the adhesive more viscous, enabling better placement of adhesive on tiles and improving adhesion.

5.   Grouts

Regarding grouting, the HPMC ingredient reduces abrasion, which protects the base material against infiltration.

6.   Self-Leveling Compounds

Adding HPMC to self-leveling compounds makes them thinner and more fluid and increases water retention. This results in a faster curing time that reduces the risk of cracking and the material shrinking and collapsing.

Conclusion

The quantity of HPMC added to dry mortar is not a lot. Still, its impact on the performance of wet mortar is quite obvious, which makes it a key additive that influences mortar performance during construction. HPMC mainly contributes to water retention, thickening, and enhancing the performance of dry mix mortars. The performance of dry mortar can be enhanced significantly by choosing the appropriate grades and proportions of HPMC.

Although HPMC is a high-tech material, its performance depends on temperature variations. This limits workability and crack resistance even under increased dosage (such as for summer formulas). Some companies have addressed this problem by increasing the level of etherification in HPMC, which allows it to retain more water at higher temperatures.

Hence, the choice and use of an appropriate grade determine the effectiveness of HPMC. Due to some unscrupulous businessmen, HPMC is adulterated, resulting in bad quality. The onus lies with corporate laboratory employees in choosing an appropriate HPMC grade. The experiments to be conducted in the laboratory ascertain the stability of mortar products to ensure quality.

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