Full-scale validation of bio-recycled asphalt mixtures for road pavements

Abstract

Recycling of asphalt has become a well-established practice in many countries, however the road pavement industry remains a bulk consumer of extracted raw materials. Novel solutions that find root in circular economy concepts and life-cycle approaches are needed in order to enable optimisation of infrastructure resource efficiency, starting from the design stage and spanning the whole value chain in the construction sector. Itis within this framework that the present study presents a full-scale validation of asphalt mixtures specifically designed to ensure durability of flexible road pavements and at the same time enabling the reuse of reclaimed asphalt pavement (RAP) through the incorporation of bio-materials as recycling agent. These bio-recycled asphalt mixtures have been first designed in laboratory and subsequently validated in a real scale experiment conducted at the accelerated pavement testing facilities at IFSTTAR. Four pavement sections were evaluated: three test sections with innovative bio-materials, and a reference section with a conventional, high modulus asphalt mix (EME2). Two tests were realized: a rutting test and a fatigue test and for each of them the evolution of bio-recycled asphalt mixtures properties as well as the pavement deteriorations were recorded and studied. Evolution of the bio-asphalt mixtures was monitored for a 5 months period after paving by a bespoke nondestructive micro-coring, extracting and recovering methodology developed at the Western Research Institute (WRI). The structural health of the pavement sections was monitored through periodic falling weight deflectometer (FWD) as well as with strain gages and temperature sensors. As a result the three tailored bio-asphalt mixtures performed similarly or better than the control mixture, both in terms of property evolutions and durability.

Definition of Optimized Indicators from Sensors Data for Damage Detection of Instrumented Roadways

“…The bituminous layer is 10.2 cm thick and made of a bituminous material with a high modulus asphalt mixture (HMAM, aka. EME2 in the previous study [ 18 ]) with 20% of reclaimed materials. The base layer is 76 cm thick, made of Unbound Granular Material (UGM) on a stone bed (50/120 mm).…”

“…The pavement considered in this paper is the fifth section from the previous study from J. Blanc et al [ 18 ]. It consists of two layers, namely a surface bituminous layer and a base layer.…”

“…During this entire fatigue test, the pavement surface temperature varied between −6 °C and 27 °C, with most values between 7 and 12 °C. The mean surface temperature was 9.3 °C, and the mean temperature in the middle of the bituminous layer was 9.4 °C [ 18 ]. Figure 5 represents the mean temperatures and their respective dates of acquisition as a function of the number of applied loads for informative purposes (the strain gauge signals being shown and discussed further in this paper).…”

“…Some pictures, that show some transversal cracks merging on the surface of the bituminous layer after a given number of loads, were taken at the end of the experimental campaign during the previous study [ 14 , 18 ]. These pictures confirm the progressive degradation of the bituminous layer.…”

Renewable binders from waste biomass for road construction: A review on thermochemical conversion technologies and current developments

“…Nevertheless, limited data on accelerated pavement testing is currently available as most studies are restricted to laboratory evaluations [108][109][110][111][112]. One study that has undertaken a full scale accelerated pavement test was Blanc et al [108], where three mixtures were designed incorporating 50% RA content with three innovative bio-materials and compared with a reference high modulus asphalt mixture. They were tested for one year in order to speed up rutting and fatigue cracking.…”