Performance evaluation of asphalt mixtures incorporating scallop shell-derived calcium carbonate as an alternative filler to hydrated lime

Rodríguez W.; Rivera J.; Otoya A.; Torres T.; Sevillano M.; Meza F.; Albornoz L.; Pocohuanca I. · Construction and Building Materials (2026) · DOI: 10.1016/j.conbuildmat.2026.147137

Resumen

In response to the need for alternative mineral fillers in asphalt mixtures, this study evaluates calcium carbonate derived from scallop shell waste (SCC) as a replacement for commercial hydrated lime (CHL), whose use in Peru is subject to regulatory restrictions. The filler dosage was defined using the critical concentration method, selecting 1.0% CHL as the reference content and 1.5% SCC as the equivalent dosage. Comparative laboratory tests were conducted to assess volumetric properties, moisture susceptibility, rutting resistance, dynamic modulus, and cracking performance. The results showed that both mixtures satisfied the required volumetric criteria. In the Hamburg wheel tracking test, the SCC mixture exhibited a mean rut depth of 4.20 mm compared to 2.54 mm for CHL. Under moisture conditioning, the CHL mixture reached a mean TSR of 86.7%, while the SCC mixture achieved 75.4%. Therefore, an adhesion-promoting additive was incorporated, allowing the mean TSR to reach 95.4%. In contrast, SCC showed improved cracking performance, with mean values of a CT index of 23 and fracture energy of 6224 J/m², compared with mean values of 14 and 4402 J/m² for CHL. The dynamic modulus results indicated a broadly comparable viscoelastic response for both mixtures under the evaluated temperatures and loading frequencies. These results indicate that the different responses of both mixtures were governed by the nature of the fillers, with CHL providing better resistance to moisture-induced damage and permanent deformation, whereas SCC contributed favourably to cracking resistance while maintaining acceptable volumetric and viscoelastic behaviour. Therefore, SCC can be regarded as a technically promising alternative filler to replace hydrated lime.

Instituciones: Universidad Peruana de Ciencias Aplicadas; Universidad San Ignacio de Loyola