Properties of calcined clay blended ASTM Type IL cementitious materials
This study investigates the feasibility of using two locally sourced, low-grade excavated clays, calcined at 800 °C, as supplementary cementitious materials in limestone-containing ASTM Type IL cement systems. The clays include calcined clay from Robertson County (CCR) and calcined clay from Cumberl...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-10-01
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| Series: | Next Materials |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2949822825005714 |
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| Summary: | This study investigates the feasibility of using two locally sourced, low-grade excavated clays, calcined at 800 °C, as supplementary cementitious materials in limestone-containing ASTM Type IL cement systems. The clays include calcined clay from Robertson County (CCR) and calcined clay from Cumberland County (CCC) in Tennessee USA, aimed at producing low-carbon limestone calcined clay cement (LC3). A comprehensive investigation was conducted on the physical and durability performance of hydrated systems in which calcined clay replaced up to 20 % ASTM Type IL cement by mass. The combination of calcined clay accelerated setting times of paste (initial by up to 60 min; final by up to 150 min), due to enhanced nucleation effects. Mortar flowability decreased by 10–20 %, attributed to higher water absorption of the calcined particles. Both clays (CCR and CCC) exhibited comparable compressive strength of mortar to the control up to 90 days, with CCR improving strength by 5–10 % for up to10 % replacement due to increasing pozzolanic activity. Drying shrinkage of mortar was reduced by 10–30 %, along with the potential contribution of internal curing effects, while microstructural observation confirmed increased hydration products. Autogenous shrinkage of paste increased by 20–120 %, driven by self-desiccation and capillary tension. Surface resistivity values of concrete remained comparable to the control, indicating minimal or slightly increased influence on chloride ion penetrability. Based on overall performance, a replacement level of 10–15 % calcined clay is recommended for sustainable LC3 cement production using these local clay sources. |
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| ISSN: | 2949-8228 |