Navigating circular economy in key construction materials – Part 1: general regulations and reuse, recycling, and circular practices for steel and timber

Abstract

Construction and demolition waste represents one of the largest waste streams worldwide and plays a central role in achieving circular economy objectives in the built environment. This study aims to systematize and synthesize recent knowledge on the potential for reuse and recycling of key construction materials - steel, timber, concrete, and bricks and blocks - at the end of their service life. The research is structured in two papers: Part 1 focuses on regulatory frameworks, recycling rates, and reuse and recycling practices for steel and timber, while Part 2 addresses concrete and bricks and blocks. The objective was to identify opportunities for reuse and higher-value recycling as more effective circular solutions. The results indicate that, although the European regulatory framework for C&DW is well developed and aligned with circular economy principles, significant gaps remain, particularly the lack of harmonized end-of-waste criteria and quality standards for most material fractions. Consequently, high reported recovery rates often conceal downcycling practices and limited material circularity. Steel exhibits consistently high recycling rates, driven by strong market demand and established regulatory criteria, while direct reuse remains marginal. In contrast, timber recovery is dominated by energy recovery, with material recycling and reuse constrained by heterogeneous material quality, limited classification systems, and insufficient policy suppor