The Influence of Metakaolin to Vaterite Ratio on the Properties of Vaterite Calcined Clay Cement: Microstructure, and Mechanical Performance
The decarbonization of cement is gaining increasing attention due to its substantial environmental impact. One promising strategy to reduce concrete’s carbon footprint is the development of low-carbon binders. Vaterite, a metastable polymorph of calcium carbonate, has recently become economically vi...
| Autores: | , , , , |
|---|---|
| Tipo de recurso: | capítulo de libro |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universidad de Navarra |
| Repositorio: | Dadun. Depósito Académico Digital de la Universidad de Navarra |
| Idioma: | inglés |
| OAI Identifier: | oai:dadun.unav.edu:10171/123743 |
| Acceso en línea: | https://hdl.handle.net/10171/123743 |
| Access Level: | acceso abierto |
| Palabra clave: | Calcined Clay Cements Vaterite Metakaolin Compressive Strength Workability |
| Sumario: | The decarbonization of cement is gaining increasing attention due to its substantial environmental impact. One promising strategy to reduce concrete’s carbon footprint is the development of low-carbon binders. Vaterite, a metastable polymorph of calcium carbonate, has recently become economically viable for large-scale production and offers significant CO2 reduction potential in cement manufacturing. This study explores Vaterite Calcined Clay Cement (VC3) as a low-carbon alternative to conventional cement, with particular emphasis on how the Metakaolin-to-Vaterite (MK/V) ratio affects the fresh and hardened properties of the composite. A comparative assessment was also conducted with Limestone Calcined Clay Cement (LC3), a widely studied sustainable binder, and Ordinary Portland Cement (OPC) as a reference. Results indicate that both VC3 and LC3 mortars exhibited reduced workability compared to OPC, primarily due to lower clinker content. However, VC3 mortars demonstrated improved workability over LC3, attributed to the spherical morphology and larger particle size of vaterite, in contrast to the finer and more irregular particles of metakaolin and limestone. Although increasing the vaterite content enhanced the workability of the VC3 mixtures, the mechanical performance of the mortars exhibited a non-linear relationship with the MK/V ratio. As the ratio increased from 1 to 3, the compressive strength (CS) at 91 days initially improved, reaching an optimal range between MK/V ratios of 2 and 2.5, beyond which it declines. Mortars within this optimal range achieved 99% to 106% of the compressive strength of OPC at 91 days, surpassing the long-term performance of LC3. The study incorporates an efficient laboratory-scale synthesis method for vaterite and employs a range of analytical techniques, including Scanning Electron Microscopy (SEM), to characterize both raw materials and hardened mortars. Results demonstrate that VC3 not only delivers superior long-term compressive strength but also offers enhanced workability, addressing a major limitation of LC3. These combined properties position VC3 as a promising low-carbon binder for future construction applications. |
|---|