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A platform for research: civil engineering, architecture and urbanism
High early pozzolanic reactivity of alumina-silica gel: A study of the hydration of composite cements with carbonated recycled concrete paste
Abstract Carbonated recycled concrete paste (cRCP) is a unique supplementary cementitious material with pozzolanic properties stemming from the alumina-silica gel. This study reveals that the high early strength of composite cements with cRCP is attributed to its rapid pozzolanic reactivity. 27Al and 29Si NMR investigations show that the alumina-silica gel is consumed after only 7 days of hydration. The rapid gel reaction results in the formation of a C-(A)-S-H phase with a low Ca/Si ratio. After 7 days, belite and remains of alite react further and increases the Ca/Si ratio of the C-(A)-S-H phase to a level typical for blended cements. As a result, a lower porosity forms already at early age, resulting in high strength. The reactivity of cRCP is influenced by its origin and carbonation conditions. Carbonation in sulfate-rich solutions enhances the gel surface area and accelerates the reaction. Slag remnants in cRCP react aiding to microstructure and strength development.
High early pozzolanic reactivity of alumina-silica gel: A study of the hydration of composite cements with carbonated recycled concrete paste
Abstract Carbonated recycled concrete paste (cRCP) is a unique supplementary cementitious material with pozzolanic properties stemming from the alumina-silica gel. This study reveals that the high early strength of composite cements with cRCP is attributed to its rapid pozzolanic reactivity. 27Al and 29Si NMR investigations show that the alumina-silica gel is consumed after only 7 days of hydration. The rapid gel reaction results in the formation of a C-(A)-S-H phase with a low Ca/Si ratio. After 7 days, belite and remains of alite react further and increases the Ca/Si ratio of the C-(A)-S-H phase to a level typical for blended cements. As a result, a lower porosity forms already at early age, resulting in high strength. The reactivity of cRCP is influenced by its origin and carbonation conditions. Carbonation in sulfate-rich solutions enhances the gel surface area and accelerates the reaction. Slag remnants in cRCP react aiding to microstructure and strength development.
High early pozzolanic reactivity of alumina-silica gel: A study of the hydration of composite cements with carbonated recycled concrete paste
Zajac, Maciej (author) / Song, Jiayi (author) / Ullrich, Patrick (author) / Skocek, Jan (author) / Ben Haha, Mohsen (author) / Skibsted, Jørgen (author)
2023-10-07
Article (Journal)
Electronic Resource
English
Performance and Hydration of Composite Cements with Carbonated, Recycled Concrete Paste
| Springer Verlag | 2023
| Taylor & Francis Verlag | 2024
89-M13 Hydration and Carbonation of Pozzolanic Cements
| Online Contents | 1993