Characterization of Three Amu-Darya Basin Clays in Ceramic Brick Industry and Their Applications with Brick Waste.

This study examined the chemical, mineralogical, physical, thermal, and technological characteristics of the Dostluk (DM), Halach (HM), and Sakar (HM) clay deposits located in the Amu-Darya basin of Turkmenistan. The potential suitability of these deposits was evaluated for the local ceramic brick industry. The chemical and mineralogical features were identified by X-ray fluorescence (XRF), ion chromatography (IC), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) techniques. The physical properties were characterized by granulometric analysis by sieving, particle size distribution, scanning electron microscopy/optic analysis, specific surface area, Pfefferkon's plasticity index, reabsorption, shrinkage, water absorption, mechanical (compression and bending), and freeze-thaw durability tests. The thermal methods were performed using dilatometry and thermogravimetric/differential thermal analyzer (TG/DTA). The test samples for the different clay deposits were extruded, dried, and fired at three different temperatures of 850 °C, 950 °C, and 1050 °C. While the Dostluk and Sakar clays have high plasticity, Halach clay has been found to have low plasticity. The mechanical and freeze-thaw durability tests demonstrated that the outcomes of the clays of different origins were sufficient, achieving compressive strengths of over 10 MPa and mass loss less than 3%, which are acceptable by industry standards. Semi-industrial processed hollow bricks demonstrated promising characteristics. While the Dostluk and Sakar clay-based brick specimens were visibly free of cracks, the Halach specimens showed some cracks. The physical and mechanical improvements of these clays were performed with three mixtures, which are M1 (80 mass% DM + 20 mass% brick waste), M2 (85 mass% SM + 15 mass% brick waste), and M3 (70 mass% HM + 25 mass% SM and 5 mass% brick waste) for the brick industry.