Characterization of Natural Gypsum Materials and Their Composites for Building Applications

Abstract

Building retrofitting plays a key-role in energy saving and a growing interest is focused on insulating materials that allow a reduction in heat loss from envelopes with low thickness, by a process of reducing heating and cooling demand. In this context, a complete characterization of the physical properties of Moroccan natural gypsum materials was carried out. Basic information on the mineralogical, microstructure, thermal, mechanical, and acoustic characteristics of the rocks sampled from two Moroccan regions is provided. It was found that mineralogy, porosity, and water content are the main factors governing the development of the structure and the strength of the samples. The measured values of the porosity were 8.94%, the water content varied between 2.5–3.0% for the two studied typologies, coming from Agadir and Safi, respectively. Gypsum powder was used for fabricating samples, which were investigated in terms of thermal and acoustic performance. Thermal properties were measured by means of a hot disk apparatus and values of conductivity of 0.18 W/mK and 0.13 W/mK were obtained for Agadir and Safi Gypsum, respectively. The acoustic performance was evaluated in terms of absorption coefficient and sound insulation, measured by means of a Kundt’s Tube (ISO 10534-2). The absorption coefficients were slightly higher than the ones of conventional plasters with similar thickness. A good sound insulation performance was confirmed, especially for Safi Gypsum, with a transmission loss-value up to about 50 dB at high frequency.

Characterization of CaCO3 Filled Poly(lactic) Acid and Bio Polyethylene Materials for Building Applications

“…The literature shows multiple methods to evaluate acoustic insulation, of which some are based on impedance tubes [ 35 , 50 ]. Transmission loss (TL) was measured according to the ASTM E2611—19 standard (“Standard Test Method for Normal Incidence Determination of Porous Material Acoustical Properties Based on the Transfer Matrix Method”) using a method developed at the Polytechnic School of Gandia and based on the impedance tubes test.…”

Softening Damage Analysis of Gypsum Rock With Water Immersion Time Based on Laboratory Experiment

“…Yu et al [21] studied the meso-structure evolution of gypsum at different salt concentrations at normal temperature, indicating significant changes in the meso-structure of gypsum crystals in different salt concentrations, affecting the physical and mechanical properties, especially permeability, extreme strength, and deformation characteristics. Bouzit et al [22] studied the conventional triaxial compression properties of anhydrite. Studies have shown that with increasing confining pressure, the deformation characteristics of anhydrite show a gradual transition from brittle to ductile nature, with peak and residual strength and confining pressure.…”

Efficient leaching process of rare earth, alkali and alkaline earth metals from phosphogypsum based on methanesulfonic acid (MSA) as green & eco-friendly lixiviant

“…The formation of CaSO 4 takes place at 180 °C with a mass loss of 3.896%. 23,24 Particle size distribution…”