The present study aimed at investigating the influence of the concentration of sodium silicate and sodium hexametaphosphate on the dispersion of an aqueous kaolinitic clay slurry regarding further use for the tape casting process. The zeta potential of the kaolinitic clay slurry matched the requirements for tape casting. The addition of magnesite in the kaolinitic slurries tended to increase the zeta potential towards the required limit values. Despite this, the further addition of surfactants allowed improving the zeta potential in agreement with the tape casting conditions. Accordingly, the rheological behavior, under continuous and oscillatory flow conditions, of various mixtures of magnesite and a kaolinitic clay was studied. Regarding the pH and the zeta potential measurements, the E–F attraction prevailed at low pH value, and F–F or E–E attraction was predominant at high pH value. All slurries exhibited a shear thinning behavior, which was well-correlated by the Herschel–Bulkley model. It appeared that the best stability for the kaolinitic clay slurries was obtained while using 0.4 mass% and 1.2 mass% of sodium hexametaphosphate and sodium silicate, respectively. An increase in the magnesite concentration above 6 mass% led to a complex behavior with low cohesion energy due to the occurrence of soluble complexes.

In recent decades, talc and kaolinite have been widely used as raw materials for the ceramic industry. In this study, the final characteristics of kaolinitic clay mixed with 6 mass% of magnesite obtained in our previous work were compared with those obtained with mixtures of kaolin (kaolin BIP) and talc (as the source of magnesium oxide). However, different amounts of talc in the kaolin powder were studied, namely 10, 30, and 50 mass% of added talc (with respect to kaolin + talc). The tape casting process was used during this work in order to manufacture the green tapes in an aqueous system with 0.2 mass% of dispersant. Subsequently, the green tapes were heated to 1000 and 1100 °C with a dwelling time of 12 min. The green and sintering tapes were characterized using the following techniques: DTA/TG, X-ray diffraction, porosity, and flexural strength analyses. The results obtained from our previous work indicate that the specimen with 6 mass% of MgCO₃ sintered at 1200 °C for 3 h exhibited the best performances, with high flexural strength and weak porosity value—117 MPa and 27%—respectively. As results from this study, the optimal mechanical and thermal properties of sintering tapes were obtained for the specimen with 10 mass% of added talc sintered at 1100 °C. Indeed, this specimen exhibited 50 MPa and 43% of stress to rupture and apparent porosity, respectively.

This investigation aims to apply the analytical method of admittance for determining the thermal performance of composite flat roofs in traditional houses located in the southern region of Algeria, characterized by hot and arid climate conditions. The effect of adding insulation to the composition of flat roofs in traditional houses is studied by varying its, type, location and thickness. In this study, nine configurations of composite flat roof systems were manufactured using multiple layers with five types of insulations. Moreover, different dynamical thermal parameters are analyzed in this study, namely time lag (TL), decrement factor (DF), admittance (Y), transmittance (U), and surface factor (SF). The main results revealed that the roof configuration of R8 with insulation based on formaldehyde board presents a high value of TL (9.94 hours) and the lowest value of DF (0.1). In contrast, the configurations without insulation addition (R1, R2, and R3) display the lowest values of TL (4.91, 4.74, and 4.81, respectively) and the highest values of DF (0.59, 063, and 0.62, respectively). This research is useful for clearly understanding the thermal performance of composite flat roofs for the improvement of the energetic efficiency of traditional buildings.

The present study aimed at investigating the influence of the concentration of sodium silicate and sodium hexametaphosphate on the dispersion of an aqueous kaolinitic clay slurry regarding further use for the tape casting process. The zeta potential of the kaolinitic clay slurry matched the requirements for tape casting. The addition of magnesite in the kaolinitic slurries tended to increase the zeta potential towards the required limit values. Despite, the further addition of surfactants allowed improving the zeta potential in agreement with the tape casting conditions. Accordingly, the rheological behavior, under continuous and oscillatory flow conditions, of various mixtures of magnesite and a kaolinitic clay was studied. Regarding the pH and the zeta potential measurements, the E–F attraction prevailed at low pH value, and F–F or E–E attraction was predominant at high pH value. All slurries exhibited a shear thinning behavior, which was well-correlated by Herschel–Bulkley model. It appeared that the best stability for the kaolinitic clay slurries was obtained while using 0.4 mass% and 1.2 mass% of sodium hexametaphosphate and sodium silicate respectively. An increase in the magnesite concentration above 6 mass% led to a complex behavior with low cohesion energy due to the occurrence of soluble complexes.

The main challenge in bioclimatic constructions using compressed and stabilized earth blocks (CSEB) is determining the optimal external wall thickness to ensure good thermal comfort. This study investigates heat transfer through opaque walls made with various CSEB samples commonly used in Algeria, using the cyclic admittance method. Five homogeneous CSEB materials were evaluated based on several dynamic thermal parameters: admittance (Y), transmittance (U), surface factor (F), decrement factor (DF), and time lag (TL). Results showed that walls made with CSEB-2 material at 40 cm thickness had the best thermal performance. Additionally, multiple linear regression (MLR) analysis was applied to predict TL and U values, yielding high coefficients of determination (R² of 0.98 and 0.79, respectively). The study concluded that TL and U values are strongly influenced by wall thickness and the compaction energy of the CSEB samples.