Influence of calcination temperature on hydration behavior, strength, and weathering resistance of traditional gypsum plaster. (27th February 2023)

• Record Type: Journal Article
• Authors: Elert, Kerstin; Bel-Anzué, Pedro; Burgos-Ruiz, Miguel
• Is Part Of: Construction & building materials. Volume 367(2023)
• Publication Date: 2023-02-27
• Subjects: Bassanite -- Anhydrite -- Surface hardness, Compressive strength -- Flexural strength -- Weathering; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2023.130361
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Detailed hydration kinetics study of gypsum calcined between 100 and 800 °C. Acceleration of bassanite due to seeded crystallization. Surface hardness increase due to filler effect of anhydrite II and uncalcined gypsum. Increase in porosity and bimodal pore size distribution in presence of anhydrite II. Abstract: The mineralogical composition, microstructure, and reactivity of traditional gypsum, a multiphase product, is closely connected to its calcination temperature, but systematic studies which relate those features to mechanical properties and weathering resistance of plasters are scarce. Here we examined the hydration behavior of gypsum calcined between 100 and 1000 °C, which contained varying amounts of uncalcined gypsum, bassanite, and/or anhydrite II. Detailed hydration and textural studies allowed the identification of the underlying mechanisms leading to differences in plaster performance related to (i) delayed hydration of anhydrite II along with modifications of the pore system; (ii) a filler effect exerted by anhydrite II and uncalcined gypsum; (iii) disruption of the plaster matrix by uncalcined gypsum; (iv) seeded crystallization in the presence of uncalcined gypsum and anhydrite II. Findings of this study further the understanding of traditional gypsum plaster performance and open opportunities for the development of sustainable building materials by designing optimized gypsum-based mixtures for specific application.