Carbon dioxide removal by enhanced concrete weathering in soil

[Geoengineering News]

https://www.sciencedirect.com/science/article/pii/S2950631X26000055

Authors: Brittany Multer Hopkins, Rattan Lal

17 January 2026

https://doi.org/10.1016/j.teengi.2026.100068

Abstract

Carbon dioxide (CO2) removal from the atmosphere is necessary to reduce negative impacts from climate change, and one method could be using waste concrete for enhanced concrete weathering (ECW) a subset of enhanced weathering. When cement paste and aggregates in concrete weather in soil, CO2 can be captured and stored as bicarbonate or precipitated as carbonates. There may be environmental ramifications from the addition of concrete to soil, both beneficial and detrimental, like increased pH, increased calcium concentrations, and possible leaching of pollutants. Despite possible negative effects like the introduction of contaminants, proper screening and application of concrete could mitigate ecological harm and ensure the environmental safety ECW. ECW studies are limited; much more research is needed on carbon movement and balance in soil systems. Future longitudinal studies are needed that encompass a variety of direct and indirect measurements in varying climactic conditions that are able to fully capture C stability and permanence from ECW. A robust and consistent testing regimen is needed to evaluate the safety of concrete for ECW and to establish concrete standard contaminant thresholds. Lastly, analysis is needed to determine the choice way to scale up ECW through material supply chains and logistics as well as creating guidelines for ECW application such as particle size and application rate recommendations.

Source: ScienceDirect