Sustainable Management of Concrete Waste and Byproducts

Concrete production and demolition generate vast volumes of waste and byproducts, including concrete slurry, hydrated cement residues and fly ash. Traditional disposal pathways, notably landfilling and uncontrolled stockpiling, pose environmental burdens via leaching of alkaline effluents, carbon dioxide emissions and resource depletion. Sustainable management focuses on recovery and reintegration of mineral constituents into construction materials, energy-efficient transformation of residues into value-added products and novel processes for carbon sequestration. Approaches under development include mechanical separation and reuse of aggregate fractions, chemical extraction of calcium and silica from hydrated cement, geopolymerisation of slurry waste to form durable binders and gas-phase carbonation technologies. Recent advances deploy microwave and supercritical techniques to reduce processing times and energy demands while enhancing CO₂ fixation. Adoption of circular economy principles underpins these strategies, promoting closed-loop systems that conserve raw materials, lower carbon footprints and deliver high-performance construction products. Implementation at industrial scale requires integrated waste collection, standardisation of processing protocols and harmonisation with building regulations to realise global environmental and economic benefits.

Research from Nature Portfolio

Innovative microwave-selective sintering techniques have been demonstrated to convert fly ash and calcium carbonate mixtures into stable carbon-storage materials while suppressing CO₂ release. By exploiting differences in electromagnetic absorption, unburned carbon phases are targeted for rapid heating, creating localised temperature gradients that facilitate aragonite formation without decomposing bulk CaCO₃. The process operates at lower overall temperatures than conventional kilns, improving energy efficiency and enabling scalable CO₂ fixation within sintered matrices suitable for roadbase and cementitious applications.

Sustainable Management of Concrete Waste and Byproducts publication trend

The graph below shows the total number of articles in sustainable management of concrete waste and byproducts across all publications each year (not limited to Nature Index journals).

Technical terms

Geopolymer: A binding material formed by alkali activation of aluminosilicate sources, offering an alternative to Portland cement with lower CO₂ emissions.

Carbonation curing: A process in which fresh cementitious materials are exposed to CO₂ gas, promoting rapid carbonate formation and strength development while sequestering greenhouse gas.

Fly ash: A silica- and alumina-rich byproduct from coal combustion, widely used as a supplementary cementitious material.

Circular economy: An economic model aimed at minimising waste and maximising resource reuse through closed-loop material cycles.

Hydrated waste cement: Residual cementitious solids generated from washing processes in concrete production, containing calcium silicate hydrate and portlandite.

References

1. Manufacturing carbon storage sintered body using microwave-selective and high-speed heating techniques. Scientific Reports (2023).
2. Sustainable resource recovery from hydrated waste cement for calcium carbonate and silica extraction: Circular economy in construction. Results in Engineering (2024).
3. Mechanical and micro properties of concrete slurry waste geopolymer under various curing conditions. Construction and Building Materials (2024).
4. Study on the properties and eco-sustainability of early-age carbonation cured cement paste with recycled concrete slurry waste substitution. Case Studies in Construction Materials (2024).
5. Effect of the Concrete Slurry Waste Ratio on Supercritical CO2 Sequestration. Materials (2023).