A sustainable recycling approach for construction: A case of remanufacturing waste rebar into steel nails

Minimizing waste in the construction industry provides economic and environmental benefits. Since steel has high embodied energy and many applications, recycling rebar waste contributes to a circular economy. This study proposes remanufacturing rebar into nails as a valuable by-product. In an experimental case-study to prove the technical feasibility of the process, short pieces of rebar waste were stripped to remove the ribs, welded into a coil, drawn to reduce the diameter, and formed into nails. The costs and technology of four alternative remanufacturing process portfolios were analyzed, giving an average profit of 576 USD/t of waste rebar. A cement consumption database was constructed based on literature data and regression analysis was applied to analyze the consumption of concrete and new rebar. The potential rebar waste was calculated assuming 3 %, 5 %, 8 %, or 10 % of the total new rebar consumption. Cement consumption data at the global and country scales were used to calculate the consumption rates of new and waste rebar to derive profit–remanufacturing potential curves. Regression analysis of these curves was performed to determine the economic sustainability degree of satisfaction (DS es ). A second approach to find DS es applied regression analysis to the remanufacturing profits for the four rates of rebar waste together. The mean DS es values (0.62–0.87) and economic sustainability index (0.33) exceed the literature threshold of 0.6 and 0.26, respectively, indicating that remanufacturing rebar waste into steel nails is an economically sustainable business. The nails can be used in the construction industry to contribute to a circular economy, thereby reducing the environmental impact of steel waste and the production of new steel nails. The overall sustainability was considered by introducing Okun's Law to ensure that profitability is not achieved at the expense of development, and weighting the importance of economic sustainability based on literature averages. Rebar is used as a standard construction material globally, so these findings have broad significance. The proposed remanufacturing process is especially relevant for less-developed economies with higher rebar waste rates to stimulate small businesses and a circular construction industry. • The mean economic sustainability degree of satisfaction (DSes) ranges from 0.62 to 0.87. • Rebar waste remanufacturing into by-product steel satisfies the threshold of 0.6≤DSes≤1. • The satisfactory economic sustainability index is 0.3. • The literature threshold of the satisfactory economic sustainability index is 0.26.