How does HPMC affect mortar at different temperatures?

Hydroxypropyl methylcellulose (HPMC) has a multifaceted impact on mortar performance at different temperatures, primarily improving key processing properties and durability.

Under high temperatures, HPMC's excellent water-retention capacity slows water evaporation, ensuring full cement hydration, helping maintain mortar strength development and reducing plastic cracking. Its thixotropic properties contribute to excellent workability, ensuring the mortar exhibits optimal viscosity and fluidity under both high and low shear conditions, improving smoothing efficiency and preventing sagging.

HPMC forms a flexible network within the mortar, alleviating internal stresses caused by temperature and humidity fluctuations, significantly reducing drying shrinkage and the risk of cracking. This polymer also enhances the bonding properties of the mortar matrix, improving flexural strength and overall toughness.

Furthermore, HPMC has a moderate air-entraining capacity, introducing small, stable bubbles, thereby enhancing the mortar's thermal insulation and freeze-thaw resistance. However, it should be noted that excessive air incorporation may negatively impact mechanical strength and should be controlled through optimized mix ratios.

Temperature also affects the solubility and solution behavior of HPMC, thereby altering its water retention and thickening efficiency. Adjusting the HPMC dosage under different climatic conditions can better suit construction needs and durability requirements.

In summary, HPMC effectively improves the overall performance of mortars in various temperature environments through mechanisms such as water retention, thickening, air entrainment, and enhanced adhesion. It is a key additive with strong adaptability and diverse functions.