A study on the moisture damage and rutting resistance of polypropylene modified bituminous mixes with crushed brick aggregate wastes

Abstract

In places where natural stone aggregates are not available, it is prudent to use locally available materials and waste product to replace the same. This study focuses on studying the rutting resistance and moisture susceptibility of bituminous concrete with crushed brick waste as aggregate when reinforced with polypropylene fibre. Seven different mixes were tested for examining the quality of crushed brick waste in bituminous concrete with two different fibre mixing methodology (wet mixing and dry mixing). Indirect tensile strength tests, resilient modulus test, and wheel tracking tests were carried out in the study in dry and wet environments. Moisture susceptibility index (MSI) and stripping inflection point (SIP) was used along with the results of wheel tracking tests at two different temperatures (25 °C and 50 °C) to characterise the moisture damage resistance and thermal resistance of bituminous concrete using crushed brick aggregate. Polypropylene modified bituminous concrete samples with crushed overburnt brick waste showed comparable rutting resistance and moisture susceptibility when compared with the control samples of natural stone aggregate. It was seen that all the mixes, other than the unreinforced brick aggregate mixes, gave satisfying rutting resistance and moisture susceptibility at 25 °C. However, at 50 °C temperature, only overburnt brick aggregate mix with 1% dry mixed polypropylene fibre gave satisfying performances in rut resistances and moisture susceptibility. Furthermore, MSI was found more reliable in understanding the moisture susceptibility of the bituminous concrete mixes than SIP. A detailed statistical analysis was also performed to study the effect of Marshall quotient and binder content on rutting rate and moisture susceptibility index.