An Experimental Investigation on Utilising RAP and PCD Waste in Bituminous Mixes for Developing Sustainable Pavement Construction Practices

Sustainable infrastructure planning and construction methods are crucial measures for achieving an adaptable built environment. Amidst considerations of road construction, a critical yet often overlooked aspect is the availability of natural resources. Consequently, there is a pressing need to adopt proven techniques that minimize investment and reduce the dependency on raw materials. The utilization of recycled aggregates emerges as a pivotal step toward achieving sustainability in the road sector and effectively managing construction waste. The present study was undertaken to investigate the potential utilisation of recycled asphalt pavement (RAP) and processed construction & demolition (PCD) waste in the dense bituminous macadam (DBM) layer of flexible pavements. Two types of bitumen (VG-30 and CRMB-55) and three aggregate types (NA, RAP and PCD) were considered to prepare sustainable bituminous paving mixes comprising of maximum proportion of waste. In the present study, the investigation was divided into three components. The first component focused at evaluation of physical and other engineering properties of bitumen and aggregates utilised in the study. The second component dealt with preparation of bituminous mixes incorporating different proportions of NA, RAP and PCD aggregates on the basis of Marshall method of mix design in order to develop sustainable modified mix, having similar or improved Marshall parameters to that of control bituminous mix (with natural aggregate). And the third component covers the performance evaluation of control and modified bituminous mixes on the basis of indirect tensile strength test and moisture susceptibility tests. Finally, it was concluded that 71% waste (30%RAP and 41%PCD) and 63.5% waste (30%RAP and 33.5%PCD) can be replaced with natural aggregates when developed using VG-30 and CRMB-55 bitumen respectively.