Effect of mixing polypropylene fibre in reinforcing non-conventional bituminous concrete

Abstract

The high demand for natural stone aggregate (NSA) in infrastructure development is having an alarming ecological impact. The study of alternative materials thus holds high research interest in terms of sustainability. The use of crushed kiln brick aggregate in pavements reinforced with polypropylene fibre (PPF) was studied in this work, with a focus on the performance differences between wet-mixed and dry-mixed bituminous concrete. Two different brick aggregates were studied along with seven different PPF contents and comparisons were made with control mixes made using NSA. The wet-mixed specimens showed comparable performance with the NSA mixes whereas the dry-mixed specimens showed performance equal to that of the control specimen. When compared with the wet-mixed non-conventional aggregate samples, the dry-mixed samples showed an increase of 6% in the resilient modulus for crushed overburnt brick aggregate mixes and an increase of 8·3% for the crushed first-class brick aggregate mixes. Fatigue and rutting tests also provided satisfactory results. The wet-mixed samples showed better performance than the dry-mixed samples in resisting permanent deformation. However, in the case of fatigue damage, the mixing method seems to have less influence as both mix types performed similarly against fatigue failure.