Comparative performance of limestone calcined clay and limestone calcined laterite blended cement concrete

Abstract

The global availability and abundance of clay soil and limestone have recently driven research for their combined use as supplementary cementitious material (SCMs). In tropical regions, laterite (which has similar chemical signature to clay) naturally abounds in larger quantities and can potentially be used in place of clay soil as SCM. This is the focus of this study which experimentally evaluates the comparative performance of concrete made from limestone calcined clay, limestone calcined laterite and calcined laterite as supplementary cementitious materials by simple test methods. The replacement of the Portland cement with these SCMs was up to 45% to achieve low-carbon cementitious materials. The cementitious materials were characterised and four concrete mixes (100% ordinary Portland cement; 15-30-55% of limestone-calcined clay-Portland cement; 30–70% of calcined laterite-Portland cement; and 15-30-55% of limestone-calcined laterite-Portland cement) were formulated to showcase their performance in terms of workability, strength, and durability. The possibility of a differing influence of varied water-to-binder ratio on the clay and laterite SCMs was also examined. The results show no significant difference between the performance of the laterite-based and clay-based blended cement concrete. It was concluded that laterite can be interchangeably used in place of clay in limestone calcined clay cements (LC3), especially in tropical regions where laterite is in abundance as much as or more than clay. Further investigation is recommended for long term performance evaluation.

Keywords

• Clay
• Laterite
• Blended cement
• Concrete performance
• Surface absorption