Analysis of the Relationship between Density and Mechanical Strength of Lightened Gypsums: Proposal for a Coefficient of Lightening

Abstract

This article develops a relationship between the reduction of density in lightened gypsum and the addition of expanded and/or extruded polystyrene waste from the construction sector and their mechanical behavior. The equations determined in this study allow us to know the flexural and compressive strengths of a lightened gypsum/plaster compound once its density is known. The results show that there is an exponential relationship between the density of the compound and its strength. The methodology followed included a compilation of the results obtained in previous research works on lightweight gypsums, analyzing the relationship between density and mechanical strength and comparing them with the equations developed in this research. The results obtained by previous researchers have a good adjustment with the proposed models, and only perlite compounds present greater deviations in the compressive strength analysis. Also, a dimensionless lightening coefficient is defined which can help to determine the best application for a lightweight gypsum compound, comparing it with an ideal lightweight gypsum.

Lightweight recycled gypsum with residues of expanded polystyrene and cellulose fiber to improve thermal properties of gypsum

“…The graph also shows the linear equation of the relationship between the density of the material and the flexural strength (Equation [3]). y = 0,0031 * density − 0,4465 [3] The results of this relationship between the two properties are compatible with those found by Santa Cruz Astorqui et al (28), where the authors concluded that there is an exponential relationship between the reduction of the composite density with the addition of EPS and its strength.…”

Analysis of Additives in Gypsum Coatings Based on Melamine, Polycarbonate Salts, Polycarboxylate, and Polycarboxylic Acids

“…In [23], a relationship was developed between the density reduction in clarified plaster and the addition of expanded polystyrene or extruded polystyrene residues from the construction sector, as well as the mechanical behavior of the additive (achieving compressive strength of 5.59 MPa). The purpose of this study was to investigate recycling, in addition to the fact that the production of calcium sulfate uses much less energy than the production of cements (70-90% less).…”

Characterization of a New Lightweight Plaster Material with Superabsorbent Polymers and Perlite for Building Applications

“…Considering the amount of potassium polyacrylate present in the mixture, Figure 4 shows how the increase in the amount of this addition has an inverse effect on the improvement of the flexural and compressive strength of the material [19]. It should be noted that the incorporation of expanded perlite in the quantities used in this research has a positive effect on the improvement of the flexural strength of the new plaster material developed [12]. However, in general terms and because of the lower density of the plasters produced, the mechanical compressive strength is reduced with the incorporation of these lightening additions [23].…”

“…Extensive research has been conducted on the incorporation of additions in gypsum composite materials to improve some of their properties. Many studies focus on a reduction in the material's own weight [11] or the improvement of its thermal properties [12,13]. For instance, W. Luan et al successfully decreased the density of gypsum composites by incorporating pregelatinized starch, phosphates, dispersant compounds and synthetic fibers for the design of prefabricated panels [11].…”