In the realm of construction and demolition waste (CDW), a groundbreaking study led by M.L. Peixoto from the Brazilian Institute for Material Joining and Coating Technologies (INTM) at the Federal University of Pernambuco has shed new light on the potential of recycled concrete aggregates in cement-based mortars. Published in ‘Next Materials’ (Proximos Materiais), the research delves into the chemical, microstructural, and mechanical behavior of these sustainable materials, offering insights that could revolutionize the construction industry and significantly reduce environmental impacts.
Peixoto and his team embarked on a comprehensive experimental program to evaluate the workability, compressive strength, and microstructural characteristics of mortars produced with CDW. The findings reveal that the maximum characteristic dimension of the grains corresponds to 2.36 mm, similar to fine sand. However, the water absorption of the recycled aggregate was notably higher at 20.1%, compared to 12.5% for fine sand. This discrepancy highlights the need for careful consideration of water content in mixtures containing recycled aggregates.
The study found that a 1:4 ratio with 30% replacement content showed better workability and compressive strength of 44.92 MPa. “This result indicates that even with high levels of CDW, the mechanical properties of the mortar can be maintained or even enhanced under specific conditions,” said Peixoto. This discovery opens up new possibilities for the construction sector, particularly in areas where access to natural aggregates is limited or costly.
Furthermore, the X-ray diffraction (XRD) results revealed diffraction peaks associated with Quartz, Portlandite, and Ettringite phases, corroborating the technical feasibility of using CDW. These findings suggest that high partial replacements of fine natural aggregate by fine recycled concrete aggregate are not only technically feasible but also sustainable. “The potential to reduce construction costs and environmental impact is immense,” Peixoto noted, emphasizing the contribution of this research to the circular economy.
The implications for the construction industry are profound. As the demand for sustainable building materials grows, the ability to incorporate CDW into cement-based mortars could lead to significant cost savings and environmental benefits. This research paves the way for future developments in the field, encouraging further exploration into the optimal use of recycled aggregates in various construction applications.
The study’s findings, published in ‘Next Materials’, underscore the importance of sustainable practices in the construction sector. By demonstrating the feasibility of using high levels of CDW in cement-based mortars, Peixoto and his team have provided a roadmap for reducing the environmental footprint of the construction industry. As the world seeks to transition towards a more sustainable future, this research offers a promising pathway for integrating recycled materials into mainstream construction practices.