Work

Performance evaluation of recycled aggregate geopolymer concrete for low-carbon breakwater systems

Year: 2025

Type: article

Abstract: Achieving circularity in the construction through the use of geopolymer concrete requires sustainable alternatives to natural virgin aggregates specially in the case of mass concrete application. However, the application of recycled aggregate (RA) in manufacturing concrete breakwaters for aggressive marine environments remains largely unexplored. A significant gap exists in comprehensive data regarding their long-term durability, leaching behavior, and mechanical performance under real-world coastal conditions. This study investigates the leaching behaviour and durability performance of a fly ash–GGBS-based geopolymer incorporating 100 % RA and compared against conventional cement and natural virgin aggregate based concrete, targeting sustainable applications in coastal breakwater structures. Key parameters evaluated include compressive strength, porosity, chloride ion migration, electrical resistivity, and the leachability of metal ions under both freshwater and seawater exposure. Results demonstrate that the cement-free RA-based geopolymer mix not only achieves comparable or superior durability, with up to 82 % improved chloride migration resistance, but also maintains low metal ion leaching well below regulatory limits in saline conditions compared to conventional OPC-based concrete. Despite a reduction in strength relative to the natural aggregate (NA)-based geopolymer, the RA-based mix achieved a 28-day compressive strength of 38.9 MPa, exceeding the 35.6 MPa of conventional OPC concrete, and exhibited significantly greater strength gain over time. The leaching behaviour of geopolymer concrete under simulated marine conditions was also revealed. Reduced porosity and enhanced microstructure further contributed to its durability highlighted the material’s viability as a durable, low-carbon alternative for marine infrastructure, supporting circular economy practices and advancing the decarbonization of coastal construction.

Source: Cleaner Waste Systems

DOI: 10.1016/j.clwas.2025.100455

Authors: K.K.Deeshani Akushla Wijesekara, Monower Sadique, Iacopo Carnacina, Veronica Torres De Sande, Ban Al-Hasani

Institution: Liverpool John Moores University

Language: English

Topic: Concrete and Cement Materials Research

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Responsible consumption and production, Industry, innovation and infrastructure, Climate action

Open Access status: gold

Estimated APC paid: $1,430