| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Revitalization of Materials through Upcycling: The 2025 Student-Led Symposium
|
| Presentation Title |
Enhancement of recycled concrete aggregate through slag-coated carbonation |
| Author(s) |
Hammad Ahmed Shah, Weina Meng |
| On-Site Speaker (Planned) |
Hammad Ahmed Shah |
| Abstract Scope |
This study aims to enhance recycled concrete aggregate (RCA) utilization in structural concrete through a novel carbonation treatment method. Carbonation of RCA is a commonly used to densify the microstructure of old adhered mortar, but it exhibits limitations due to low available calcium content in RCA for reacting with CO2. To address this, RCA is coated with blast furnace slag before carbonation. This approach offers two benefits: (1) introducing external calcium for microstructure densification through higher production of calcium carbonate, and (2) providing silica to facilitate a pozzolanic reaction, enhancing bonding with new concrete. Pressurized and wet carbonation techniques were employed and compared. The slag-coated RCA showed significant improvements, with up to 40% reduced water absorption and 65% increased bond strength after carbonation. Pressurized carbonation enhanced CO2 penetration and calcium carbonate production, forming needle-like aragonite that improved the RCA-concrete bond. These findings were validated using TGA, XRD, and SEM-EDS analyses. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Surface Modification and Coatings, Recycling and Secondary Recovery, |