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Cement substitution with calcined kaolinite–montmorillonite clay blends as an effective way to suppress alkali-silica reaction in cement composites containing reactive aggregates is investigated. Expansion, cracking behavior, mechanical properties and microstructure of the cement composites were investigated. Hydration of the ternary cement blends was also characterized. The results indicate that cement modification with a combination of calcined kaolinite–montmorillonite clays can effectively mitigate alkali-silica reaction-induced deteriorations. By incorporating 30% clays, the volume expansion of the cement composites was decreased from deleterious to innocuous level. Amount of cracks was decreased with increasing clay incorporations. In the presence of combined calcined clays, the strength gain of the cement composites is more significant the strength loss caused by alkali-silica reaction indicating the effective mitigation of this virulent reaction in concrete.
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Hydration and mixture design of calcined clay blended cements: review by the RILEM TC 282-CCL
Abstract The RILEM technical committee 282-CCL: Calcined Clays as Supplementary Cementitious Materials, investigates all the aspects related to calcined clays, from clay exploration and characterization to calcination process, hydration reactions and concrete properties. This white paper focuses on the hydration mechanisms of calcined clay-blended Portland cements, covering both 1:1 and 2:1 calcined clays. The pozzolanic reaction of calcined clay is detailed, and the main reaction products are described. The differences observed depending on the clay type are also discussed, as well as the potential influence of the secondary phases present in calcined clay. The factors controlling and limiting the reaction of calcined clay are investigated, evidencing the role of porosity saturation and refinement of the microstructure. The complete characterisation of the hydration of calcined clay cements is made possible by the determination of the reaction degree of calcined clay. Several methods are compared to estimate the extent of calcined clay reaction. The influence of clinker and limestone mineralogy are also discussed. Finally, guidelines for optimising the mixture design of calcined clay blended cements are provided, with special attention to sulphate adjustment and clinker factor.
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- Award ID(s):
- 1903457
- PAR ID:
- 10470105
- Publisher / Repository:
- RILEM
- Date Published:
- Journal Name:
- Materials and Structures
- Volume:
- 55
- Issue:
- 9
- ISSN:
- 1359-5997
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1617/s11527-022-02060-1
