Description
ABSTRACT: Sequestration of carbon is a vital process for the future of the planet to reduce the effects of climate change. One option is to amend soils with basic silicate rock quarry fines or construction and demolition wastes. This promotes carbonate precipitation and sequestration of soil inorganic carbon (SIC), thereby facilitating sequestration of CO2 emissions; and providing an alternative and sustainable route for industrial by-product management.Over an 18-month monitoring period at a major urban redevelopment site, CO2 was quantified at ~85 tonnes of CO₂ per hectare (equivalent to 8.5 kg CO₂ m⁻²) through the formation of pedogenic calcite. The calcite formed due to the rapid weathering of calcium silicate and hydroxide minerals originating from the demolition of concrete structures. Isotopic analyses, including radiocarbon (¹⁴C) and stable carbon and oxygen isotopes, confirmed that the carbon incorporated into the calcite was derived from atmospheric CO₂. Extrapolating these findings suggests that the strategic management of fewer than 12,000 ha of urban land to enhance calcite precipitation could facilitate the removal of approximately one million tonnes of atmospheric CO₂ annually. Work at other sites showed that the occurrence of pedogenic carbonates was widespread in artificially created urban soils containing Ca and Mg silicate minerals.
A three-year controlled pot experiment at Cockle Park Farm, Northumberland, UK, was conducted as part of the SUCCESS Project to evaluate plant performance and carbon sequestration potential on engineered soils derived from construction materials. Twenty-five plant species representing diverse functional groups including grasses, forbs, legumes, woody plants, and energy crops were cultivated in soils composed of either crushed demolition concrete or dolerite, each mixed at a 30:70 ratio with sand and overlaid with a layer of compost. Plants grown in the concrete-based substrate exhibited notably higher survival rates (95%) compared to those grown on dolerite (87%). Moreover, the concrete treatments consistently supported greater above- and below-ground biomass across all plant functional groups. Enhanced carbon capture performance was also observed, with nearly all concrete treatments showing measurable increases in total inorganic carbon (TIC) within the first growing season. Findings demonstrated that demolition-derived concrete can be effectively repurposed as a soil amendment capable of supporting diverse vegetation establishment while actively sequestering atmospheric CO₂ through carbonate mineral formation.
A third study presents data from experimental engineered soil plots composed of basalt–sand and concrete–sand mixtures established in 2015. Soil samples collected in summer 2021 were analyzed to quantify changes in total, organic, and inorganic carbon since the initial establishment. From this, a lysimeter experiment was designed to investigate the geochemical mechanisms driving carbonate precipitation and pedogenic calcite formation within engineered soils over a year-long period.
The findings from this research suggest that using crushed concrete from demolition to build a carbon capture function into soils could facilitate landscaping and reconstruction of soils after a conflict. Such approaches hold significant promise for post-conflict reconstruction and urban restoration contexts, where demolition rubble is abundant and soil/ecological recovery is a critical priority.
| Period | 27 Nov 2025 |
|---|---|
| Held at | Soils Protection Institute of Ukraine, Ukraine |
| Degree of Recognition | International |