A new low carbon clay based concrete with improved water resistance
A simple, low impact and robust additive solution to simultaneously improve the workability and water resistance of poured earth.
Decarbonizing the construction industry is urgently needed in light of the climate change. With the projected global population growth and urbanization progression, eco-friendly alternative building materials are required. Building with locally available earth materials can answer this need. Poured earth, or self-compacted clay concrete, is the new development in contemporary earthen construction. Thanks to its good workability achieved with the associated superplasticizers, poured earth can be cast directly into a mold, and it then gradually solidifies and sets with the help of coupled superplasticizer inhibitors, making it fast to produce, easier to work with, and more acceptable to/by the current construction sector.
In this project, we developed a new type of poured earth with improved water resistance based on natural tannins. In combination with alkali, the dispersing effect of tannins toward clay particles can be greatly increased, while the simultaneously added iron compound enables the gradual coagulation of dispersed clay. All three combined after drying bring an additional function to the material: protection to water disaggregation. By proposing a simple and robust additive solution to simultaneously improve the workability and water resistance of poured earth, this research delivers inspiration for designing other types of poured earth with additional functionalities.
Related publications
- Du, Y., Brumaud, C., Winnefeld, F., Lai, Y. H., & Habert, G. (2021). Mechanisms for efficient clay dispersing effect with tannins and sodium hydroxide. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 630, 127589.
- Du, Y., Habert, G., & Brumaud, C. (2022). Influence of tannin and iron ions on the water resistance of clay materials. Construction and Building Materials, 323, 126571.
- Du, Y., Habert, G., & Brumaud, C. (2022). Design of Tannin-Based Poured Earth Material via Deflocculation–Coagulation Control: Additive Selection and Tannin Variation. ACS Sustainable Chemistry & Engineering, 10(44), 14495-14502.
- Du, Y., (2023). A new low carbon clay based concrete with improved water resistance. Doctoral thesis, ETH Zurich.
The chair of Sustainable Construction intends to embed sustainability in all aspects of the built environment. For more information, please visit our website.