Exploring the use of recycled coarse aggregates from different sources in Self-Compacting Concrete for sustainable building

Abstract

The construction industry depends heavily on Natural Aggregates (NA), leading to major environmental and economic issues due to extraction costs and resource loss. Recycled coarse aggregates (RCAs) from Non-Harmful Construction and Demolition Waste (NHCDW) are the best alternative for Self-Compacting Concrete (SCC). This study looks at the performance of SCC using different types of recycled gravels from NHCDW, such as concrete, bricks, bitumen, roof tiles, and plastics (PVC). The fresh and hardened states of SCC were analyzed, with measurements taken for workability, porosity, density, and mechanical strength. The findings indicated that the substitution of recycled gravels resulted in adequate performance, except when 85% of recycled brick gravel was replaced with natural gravel. However, a slight decrease in mechanical strength was observed for all mixes. The results indicated that SCC with up to 85% recycled concrete coarse aggregates maintained satisfactory rheological and mechanical properties. However, replacing 85% natural gravels with recycled bricks gravels led to an 18.5% reduction in mechanical properties compared to the reference, failing to meet the requirement. In general, the mechanical strengths, including compressive, and tensile strength decreased by 8.8% to 18.5% and 9.2% to 14.8 % respectively, compared to the reference.

These findings provide valuable insights into the limited values of coarse aggregates from NHCDW materials for concrete purposes. This study is part of the work in the European project 101091679-MOBICCON-PRO (MOBile and Innovative Circularity for Construction Products) framework-Horizon-Cl4-2022-Twin-Transition-01. This research aids sustainable construction by providing guidelines for using RCA in concrete, which lowers environmental impact and supports the circular economy.