materials Article Characterization of Three Amu-Darya Basin Clays in Ceramic Brick Industry and Their Applications with Brick Waste Serdar Korpayev 1,2, * , Meretdurdy Bayramov 1 , Serdar Durdyev 3, * and Hemra Hamrayev 4   Citation: Korpayev, S.; Bayramov, M.; Durdyev, S.; Hamrayev, H. Characterization of Three Amu-Darya Basin Clays in Ceramic Brick Industry and Their Applications with Brick Waste. Materials 2021, 14, 7471. https:// doi.org/10.3390/ma14237471 Academic Editor: Irina Hussainova Received: 28 October 2021 Accepted: 3 December 2021 Published: 6 December 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Economic Society “Dowletli-Dowran”, Halach District, Lebap Velayat, Khalach 746632, Turkmenistan; meretdurdyb@gmail.com 2 Department of Chemistry, Hacettepe University, Beytepe, Ankara 06800, Turkey 3 Department of Engineering and Architectural Studies, Ara Institute of Canterbury, 130 Madras Street, Christchurch 8011, New Zealand 4 Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, Kuala Lumpur 54100, Malaysia; hhamrayev@gmail.com * Correspondence: serdarkorpe@gmail.com (S.K.); Serdar.Durdyev@ara.ac.nz (S.D.) Abstract: 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. Keywords: clays; Amu-Darya basin; ceramic brick; characterization; building industry 1. Introduction The building industry has an important role in the economic development of develop- ing countries as it is directly related to many industries, such as cement, concrete, steel and other metals, glass, tile, and bricks [1]. One of the most important of these sectors is the brick industry, which has a global production of approximately 1.391 trillion pieces in 2014 annually [2]. Clays are among the most frequently used and versatile materials in industrial fields, such as the petroleum industry; they are also used in the composition of foundry molds, paint, paper coatings and fillings, pharmaceuticals, and water treatments (catalysis, ad- sorbents, ion exchangers) [3–6]. Clays are also essential components of ceramic products and building materials [7]. It is important to understand the features of clays for diverse Materials 2021, 14, 7471. https://doi.org/10.3390/ma14237471 https://www.mdpi.com/journal/materials