Hydroxypropyl methylcellulose HPMC can significantly improve the water retention of mortar. A lower dosage of hydroxypropyl methylcellulose HPMC can significantly improve the water retention rate of mortar. When the dosage is 0.02%, the water retention rate increases from 83 % rose to 88%; when the dosage was 0.2%, the water retention rate reached 97%. At the same time, the low content of HPMC also significantly reduces the degree of delamination and bleeding rate of the mortar, which shows that HPMC can not only improve the water retention of the mortar, but also significantly improve the cohesion of the mortar, which is important for the uniformity of the mortar construction quality. very favorable.
However, hydroxypropyl methylcellulose HPMC has a certain degree of negative impact on the flexural strength and compressive strength of mortar. With the increase of hydroxypropyl methylcellulose HPMC content, the flexural strength and compressive strength of mortar gradually decreased. At the same time, hydroxypropyl methylcellulose HPMC can increase the tensile strength of mortar. When the content of hydroxypropyl methylcellulose HPMC is within 0.1%, the tensile strength of mortar increases continuously with the increase of HPMC content, while When the content exceeds 0.1%, the tensile strength will no longer increase significantly. Hydroxypropyl methylcellulose HPMC can also significantly increase the compressive shear bond strength of mortar. Adding 0.2% HPMC can make the mortar bond strength from 0.72MPa increased to 1.16MPa.
Studies have shown that hydroxypropyl methylcellulose HPMC can significantly prolong the cooling time of mortar and significantly reduce the slippage of mortar, which is very beneficial for tile paste construction. When HPMC is not added, the bond strength of the mortar cooled for 20 minutes decreases from 0.72MPa to 0.54MPa. After adding 0.05% and 0.1% HPMC, the bond strength of the mortar cooled for 20 minutes is 0.8MPa and 0.84MPa, respectively. When HPMC is not added, the slippage of the mortar is 5.5mm. With the increase of HPMC content, the slippage decreases continuously. When the content is 0.2%, the slippage of mortar drops to 2.1mm, and the slippage is greatly reduced. And other thin-layer construction provides technical support.
In addition, hydroxypropyl methylcellulose HPMC can effectively inhibit the formation of plastic cracks in mortar and significantly reduce plastic cracks. When the content of HPMC is low, the crack index decreases significantly with the increase of the content of HPMC. When the content of HPMC is 0.1% and 0.2%, the relative crack index of mortar is 63% and 50%, respectively. After the content of HPMC exceeds 0.2%, The plastic cracks of the mortar are no longer significantly reduced.
Post time: Apr-11-2023