Lightweight Gypsum Materials with Potential Use for Thermal Insulations

Abstract

This article presents the influence of three additions i.e., hydroxyethyl methyl cellulose (HEMC), sodium bicarbonate and flue gas desulfurization (FGD) gypsum on the porosity of gypsum-based materials. The specific microstructure for a material with good thermal insulation properties i.e., numerous closed pores distributed in the binding matrix, was achieved using HEMC (0.3 wt.%) and sodium bicarbonate (0.5–2 wt.%). The addition of HEMC to the gypsum binder determines, as expected, an increase of the porosity due to its ability to stabilize entrained air. In the case of a sodium bicarbonate addition, the pores are formed in the binding matrix due to the entrapment of the gas (CO2) generated by its reaction. Sodium bicarbonate addition delays the setting of gypsum binder therefore in this study FGD gypsum (waste produced in the desulfurization process of combustion gases generated in power plants) was also added to the mixture to mitigate this negative effect. The decrease of geometrical density (up to 13%, in correlation with the additive nature and dosage) correlated with the increase of the porosity, determines, as expected, the decrease of flexural and compressive strengths (33–75%), but improves the thermal properties i.e., decreases the thermal conductivity (9–18%).

Characterization of a New Lightened Gypsum-Based Material Reinforced with Fibers

“…Evans et al [12] developed a new method for the preparation of semi-dry plaster mortars, which incorporated expanded perlite with glass fibers. The fact that these lightened plaster materials are easily applicable on site and have good thermal resistance leads to their incorporation as rehabilitation materials, even improving the results obtained with porous materials made with Portland cement [13]. Finally, we find authors who have focused their research on reducing the weight of plaster materials based on circular economy criteria and the incorporation of waste, such as the addition of polyamide powder waste or plastic cable waste [14,15].…”

Application of the Industrial Byproduct Gypsum in Building Materials: A Review

“…Lightweight porous materials were prepared using DG, NaHCO 3 , and hydroxyethyl methyl cellulose [71]. It was found that by adding hydroxyethyl methyl cellulose, the void fraction of the material was significantly increased.…”

“…Mainly, the increase in e ringite in the system and the mesh architecture of C-S-H made the architecture more dense, which had a significant effect on the strength enhancement. Lightweight porous materials were prepared using DG, NaHCO3, and hydroxyethyl methyl cellulose [71]. It was found that by adding hydroxyethyl methyl cellulose, the void fraction of the material was significantly increased.…”

Synthesis and Characterisation of Hemihydrate Gypsum–Polyacrylamide Composite: A Novel Inorganic/Organic Cementitious Material

“…To tailor the initial setting time and bolster the mechanical strength of gypsum materials, significant research has focused on their modification, such as the incorporation of organic polymers and inorganic additives into gypsum systems [8][9][10][11][12][13]. Yu et al notably enhanced the toughness and strength of composites by integrating organic and inorganic units at a molecular scale into an inorganic base [14].…”