This study first prepared two glass-ceramic lightweight aggregates (labeled BD and BW) using glass and sludge from two different resources. Their matrix composition and microstructure were then compared with those of conventional aggregates, including shale and fly ash aggregates. The results show that the formation of diopside phase significantly enhances aggregate strength. BD exhibits a single-particle strength of 20.7 MPa and an apparent density of 1.75 g/cm³. However, because of the high flux content, the increased Fe₂O₃ content in the BW group resulted in a coarser, uneven pore structure, which limited its strength development (11.01 MPa at 1.53 g/cm³) compared with the BD group. Pore structure and distribution are critical determinants of aggregate performance. The fly ash aggregate shows a loose internal and external structure, resulting in high water absorption (16.89 %) and low strength (9.82 MPa). The shale aggregate has uneven pore distribution (multimodal distribution), limiting strength improvement (9.61 MPa). A dense glaze layer formed on the surface of the glass-ceramic aggregate effectively reduces water absorption but weakens the bond with the cement matrix. However, the internal glass phase still maintains high pozzolanic activity, and the Al leaching amount of the crushed BD group increases by 63 %.