Strength Enhancement of Aluminosilicate Aggregate Through Modified Thermal Treatment

Abstract

Commercial aluminosilicate aggregates derived from kaolinite and bauxite were evaluated for various physical and mechanical properties. Suites of thermal treatments based on known phase relationships were performed, resulting in significant modification of microstructural and crystalline phase evolution. These structural changes were evaluated and rationalized via scanning electron microscopy and X‐ray diffraction, respectively. Subsequent measurement of mechanical strengths by diametral compression and density by gas pycnometry indicated increases in overall strengths (up to 24%) at a comparable densities (approximately 2.8 g/cm3) in kaolinite‐derived aggregates. Results of this study are being used to drive processing modifications to achieve higher specific strength in aluminosilicate‐derived aggregates.