Circular economy, data analytics, and low carbon concreting: A case for managing recycled powder from end-of-life concrete.

• Reuse of the mineral rich recycled concrete powder (RCP) as supplementary cementitious material (SCM) is under exploited. • Meta-analysis reveals that 15% replacement of the binder with non-beneficiated RCP can reduce target strength by up to 40% compared to granulated blast-furnace slag (GGBS). • Reduction in the eCO 2 of concrete containing the CO 2 -injected RCP becomes significant above 30% binder replacement. This can reach 10–25% of that achievable with GGBS. • Treating RCP with waste CO 2 can lead to carbon negative SCM and it presents the most promising route for managing end-of-life concrete in the circular economy. Reuse and recycling are vital practices in the circular economy. Despite progress in recycling aggregates from end-of-life concrete, the potential for reusing recycled concrete powder (RCP) as supplementary cementitious material (SCM) is now attracting research and commercial interest. Herein, a meta-analysis of concrete in which RCP was used as an SCM was conducted, and a multivariate regression model was developed for predicting strength from mix composition. The carbon footprint of alternative beneficiation strategies, including milling only, milling plus thermal treatment and milling plus CO 2 injection, were quantified and used with the regression model to investigate RCP-containing concrete's embodied carbon (eCO 2). The comparison was made with conventional SCMs and end-of-life scenarios of concrete from different cement types. The meta-analysis and regression model showed that 15% cement replacement by the non-beneficiated RCP caused a 40% reduction in 28-day compressive strength, and at 50% replacement, the strength reduction was 70%. Above 30% cement replacement, the RCP beneficiated through CO 2 injection reduced the concrete's eCO 2 per unit strength by 10–25%, while the thermally treated RCP had greater eCO 2 than conventional SCMs. Thus, circularising end-of-life concrete does not guarantee low carbon concrete production. Instead, treating RCP with waste CO 2 leads to a carbon-negative SCM, presenting the most promising route for low-carbon concrete in the circular economy. [Display omitted] [ABSTRACT FROM AUTHOR]