Australia: Researchers at RMIT University in Melbourne have used low-grade clay to produce a supplementary cementitious material that can replace up to 20% of cement in concrete. The process mixes equal portions of illite and kaolin clays and heats them at 600°C. The resulting material increases the compressive strength of concrete by 15% and reduces its porosity by 41%, compared to exclusively ordinary Portland cement-based concrete. Writing in the Journal of Engineering, the team reported that the co-calcination of the materials increases disordered material by 18%, enhancing binding ability.
Lead author Roshan Jayathilakage noted the ‘economic and environmental’ scalability of the process.
