Impact crushing of waste concrete for coarse aggregate liberation by water jet

• Published in: Powder technology 2024-03, Vol.436, p.119513, Article 119513
• Main Authors: Wang, Zefeng, Pan, Chao, Jiang, Yutao, Zhong, Jinwen, Tang, Jie
• Format: Article
• Language: English
• Subjects: Aggregate liberation; Particle size distribution; Residual adhered mortar removal; Shape factor; Waste concrete recycling; Water-jet impact
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2024.119513

This study presents an innovative approach for waste concrete recycling using water-jet impact (WJI) method. The liberation behavior of coarse aggregates subjected to WJI is discussed; the properties of the recycled concrete aggregate (RCA) are characterized; and the reuse performance of RCA is evaluated. Results show that high fluidity and high penetrability of jet flow help achieve complete liberation of coarse aggregates. Jet flow penetrates and further erodes interfacial transition zone, resulting in efficient residual adhered mortar (RAM) removal. The obtained RCA is of high quality with an extremely low RAM content and water absorption of approximately 2.50% and 0.52%. A suitable jet pressure is recommended to obtain a complete RCA with more spherical and fewer flaky particles. The concrete mixture made of RCA from WJI exhibits better performance than that made of RCA from mechanical crushing. These findings confirm that WJI is an effective approach for waste concrete recycling. [Display omitted] •High fluidity and high penetrability help achieve complete aggregate liberation.•Jet erosion on ITZ leads to efficient removal of residual adhered mortar.•The obtained RCA owns extremely low mortar content and water absorption.•RCA show excellent reuse performance despite polished surface and spherical shape.•There exists an optimum jet pressure towards high–quality RCA production.