Laboratory-scale particle-level evaluation of MSWIFA-RCA granulated artificial aggregates with 2D–3D morphology-assisted screening

Abstract

Recycled concrete aggregate (RCA) and municipal solid waste incineration fly ash (MSWIFA) can be co-processed into granulated artificial aggregates, but conventional batch-averaged assessments cannot adequately reveal particle-to-particle consistency, while existing single-particle methods generally examine strength or morphology as isolated attributes. It also remains unclear whether two-dimensional (2D) descriptors can serve as rapid surrogates for selected three-dimensional (3D) morphological parameters. This study establishes a particle-level evaluation framework for aggregates comprising an RCA core coated with a physically pretreated, MSWIFA-bearing cementitious layer. The effects of water-to-solid ratio (W/S), paste-to-aggregate ratio (P/A), and rotational speed were assessed through particle size distribution, apparent density, 24 h water absorption, single-particle compressive strength, and 2D-3D morphology correlations. Raising W/S from 0.10 to 0.20 lowered water absorption from about 25.0% to 18.3% at P/A = 3 and from 25.5% to 17.0% at P/A = 4, whereas apparent density changed only slightly and non-monotonically. At W/S = 0.15, P/A = 4, and 30 rpm, a representative C2 particle with an equivalent diameter of approximately 10 mm exhibited a 28 d strength of 3.17 MPa. Coefficients of variation of 16.1–20.7% indicate appreciable particle-to-particle strength scatter, showing that mean strength alone cannot characterize batch-level mechanical reliability. For the tested C-series particles, empirical relationships between selected 2D descriptors and their 3D counterparts reached coefficients of determination of 0.876–0.998, although external morphology alone did not reliably predict particle strength. Within the tested material and size ranges, the framework supports laboratory-scale comparison of granulation conditions and morphology-assisted screening, while still relying on physical and mechanical testing for performance assessment.

The authors' abstract, as published at the source. Construction and Building Materials, 2026 · DOI ↗