Abstract:
The transition from a linear to a circular
economy is essential for addressing resource depletion,
construction and demolition (C&D) waste generation,
and agricultural biomass disposal in the construction
industry. Sri Lanka faces growing challenges associated
with rapid infrastructure development and the
underutilization of waste resources, particularly recycled
concrete waste and coconut shell residues. Although
recycled aggregate concrete (RAC) and agricultural
waste-derived biochar have been widely investigated as
sustainable construction materials, their integrated
application within a circular economy framework
remains limited.
The review specifically focuses on two selected waste-
resource pathways: the recovery of C&D concrete waste
as recycled aggregate for concrete production and the
valorisation of coconut-shell waste as biochar for
incorporation into recycled aggregate concrete. This
study presents a PRISMA-based systematic literature
review evaluating the circular economy potential of
construction and agricultural waste through the
utilization of recycled aggregate concrete and coconut
shell biochar (CSB). Peer-reviewed journal articles and
conference papers published between 2011 and 2026 were
identified from major scientific databases and
synthesized using thematic analysis following PRISMA
screening and eligibility assessment.
The review indicates that recycled aggregates reduce
dependence on virgin construction materials while
supporting effective C&D waste management. Coconut
shell biochar enhances the mechanical properties,
durability, microstructural performance, and alkali–
silica reaction resistance of recycled aggregate concrete.
The review also highlights Sri Lanka's Construction and
Concrete Waste Recycling Centre as a significant step
towards circular construction.
Based on the synthesized evidence, this study proposes
a Construction–Agriculture Circular Resource Loop
Framework that integrates construction and agricultural
waste into a unified circular economy model for
sustainable infrastructure development in Sri Lanka. The
framework provides practical guidance for policymakers,
researchers, and industry to advance resource circularity
through integrated waste valorisation strategies.
