Essential Improvements in Gypsum Mortar Characteristics

Document Type : Original Article


1 Department of Civil and Environmental Engineering, Amirkabir University of Technology

2 Department of Civil Engineering, Qom University, Qom, Iran

3 Department of Civil Engineering, Shahrekord University, Shahrekord, Iran


< p>Gypsum mortar is a common building material that can be used especially for plastering the walls. This mortar has three important weaknesses which can limit the gypsum mortar for building and statue construction. First; it has low compressive strength. Second; it has high water absorption, and third; it has low setting time. In the current study, cement, Nano silica, and a superplasticizer with polycarboxylate ether were used for solving the problems. The results showed that using cement with providing C-S-H can improve the mortar strength trend line. The results showed significant growth of 28th day compressive strength (from 9 MPa to 45 MPa). Using Nano silica increases the compressive strength by making C-S-H dense and decreases the water absorption to 1/3 of the control sample.  Consuming polycarboxylate ether causes the uniform dispersion of Nanoparticles through mortar. This even diffusion blocks the pores and reduces their mean dimensions. The ANOVA test was used to find the main effective parameters on the 28th day compressive strength, water absorption, and setting time. In this regard, Nano silica (49.82% contribution), cement content (56.68% contribution), and superplasticizer (73.10% contribution) have the main roles in compressive strength, water absorption, and setting time, respectively. 


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