Study on the influence of polycarboxylic acid water-reducing agent on the performance of gypsum-modified mud mortar
DOI:
https://doi.org/10.54355/tbus/27897338.6.2.2026.0103Keywords:
desulphurization gypsum, polycarboxylate water reducing agent, denseness, water-retaining property, compressive strengthAbstract
Masonry mortar, as the primary bonding material in adobe construction, plays a crucial role in the integrity of adobe masonry due to its working properties, compressive strength, and shrinkage rate. Based on the use of industrial by-product gypsum for sustainable material modification, gypsum and polycarboxylate superplasticizer were added to address the defects of the masonry mortar and explore their impact. The effect of gypsum on the compressive strength of the mortar specimens exhibited a trend of initially decreasing, then increasing, and eventually decreasing again within a certain range. The experiment found that a 20% gypsum content led to the greatest improvement in compressive strength, reaching 3.12 MPa, which is 1.49 times that of the plain mortar specimens. However, adding gypsum alone negatively affected the mortar's consistency, water retention, and volume shrinkage. Therefore, a combination of polycarboxylate superplasticizer and gypsum was studied to evaluate the mortar's performance. The experiment showed that polycarboxylate superplasticizer effectively improved the consistency and water retention of the gypsum-modified mortar, enabling it to meet the required consistency for masonry under low water-to-soil ratios. The optimal dosage of the superplasticizer ranged from 0.5% to 1.0%, which significantly improved the consistency and water retention properties, with water retention reaching up to 99%. Polycarboxylate superplasticizer also improved the volume shrinkage of the gypsum-modified mortar. With 1% superplasticizer, the volume shrinkage rate of the mortar specimens was reduced to below 10%, almost half of the shrinkage rate of the unmodified mortar. The compressive strength of the gypsum-modified mortar also showed significant improvement with the addition of the superplasticizer. The compressive strength of the mortar increased with the amount of superplasticizer, and when 20% gypsum and 1.5% superplasticizer were mixed, the compressive strength of the mortar specimens reached 5.96 MPa, which is 2.84 times higher than that of the plain mortar specimens.
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Copyright (c) 2026 Sawulet Bekey, Wumeng Liu, Qing Wang, Wenze Wang, Jingzheng Mi
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Funding data
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National Natural Science Foundation of China
Grant numbers Grant No. 52268045: Experiment Research and Mechanism Analysis on Mechanical Properties of Composite Mesh Reinforced Adobe Masonry Structure
