Utilizing non-kaolinitic clays for low-cost ecological mixed cement

abstract

English

For decades, research has focused on clays and calcined clays, predominantly kaolinite and calcined kaolinite. However, recent economic fluctuations have increased the cost of these materials. Consequently, this study investigated the potential of non-kaolinitic clays as supplementary cementitious materials (SCMs). Natural clay samples, originally deemed as waste, from local sources were selected. The recently authorized EN 197-5 standard permits up to 50% cement substitution, exceeding the previous 35% limit.1 Therefore, cement-clay mixtures with up to 60% clay substitution were prepared and evaluated for workability, CO2 emissions and compressive strength over time. This study demonstrates the viability of non-kaolinitic calcined clays as effective SCMs, offering a sustainable and abundant resource. While high cement replacement levels may lead to a 10-30% reduction in flexural and compressive strength, the reduced material cost compensates for this trade-off. On the other hand, lower cement replacement leads to usually 10% higher compressive strength compared to reference sample of pure Portland cement. The utilization of these cost-effective cement-clay mixtures has the potential to enhance both economic and ecological sustainability by reducing Portland cement consumption and associated carbon dioxide emissions

calcined clay, non-kaolinitic clay, cement

FLORIAN, V.; ŠILER, P.; KUNOVSKÝ, O.

9. 4. 2025

University of Split

Split

https://zorh.ktf-split.hr/wp-content/uploads/2025/04/Program_ZORH.pdf