Nationwide recycled steel slag pavements can stimulate sustainable urban transportation

Urban road expansion supports economic growth but also locks in emissions and resource demand. A bottom-up, high-resolution framework was developed to assess national-scale climate, health and economic impacts of recycled steel slag pavements. Taking China as a representative case, the framework integrates pavement degradation with nationwide data on traffic demand, road networks, and steel slag availability to evaluate renovation and cross-regional allocation strategies. Here we show that durable recycled pavements extend service life, reduce use-phase emissions, and generate system-level benefits. Across assessment horizons accounting for phased deployment and two subsequent 15-year service cycles, replacing 25–100% of urban pavements is estimated to reduce greenhouse gas emissions by 19% (431–1741 million tonnes), cut fine particulate matter emissions by 13% (303–1229 million kilograms), avert approximately 31,802–128,980 premature deaths, and generate net economic benefits of 3.48–15.01 trillion Chinese Yuan. These findings identify recycled pavements as a strategy for sustainable urban transport and climate resilience. Recycled steel slag pavements could cut emissions by 19%, reduce fine particle pollution by 13%, prevent up to 128,980 premature deaths and deliver major economic gains, according to a national high-resolution model of roads, traffic, pavement degradation and steel slag supply.