Ageing evolution of foamed warm mix asphalt combined with reclaimed asphalt pavement

Abstract

ABSTRACT:The combination of high rates of reclaimed asphalt pavement (RAP) and warm mix asphalt (WMA) technologies is still ambiguous in terms of durability. With the aim of clarifying this issue, a study comparing a hot mix asphalt with a WMA prepared using the foaming process technology. Both mixes contain 50% of RAP and are submitted to a laboratory ageing procedure. The long term related performance of the mixtures is compared by means of complex modulus and fatigue testing. Penetration and ring and ball tests are undertaken on the recovered bitumens, as well as the ageing evolution, characterised by the Fourier Transform Infrared analysis. Finally, the Apparent Molecular Weight Distribution (AMWD) of the binders is calculated from rheological measurements using the δ-method. Results show a relation between ageing evolution and mechanical performance. After ageing, the overall tendencies are similar for both processes. RESUMEN: Evolución del envejecimiento en mezclas espumadas semicalientes con áridos reciclados.El comportamiento de mezclas asfálticas semicalientes (WMA) con alto contenido de material reciclado (RAP) es aún incierto a largo plazo. Por este motivo, en este estudio se compara el envejecimiento una mezcla caliente convencional y una mezcla espumada semicaliente con 50% de RAP. Ambas mezclas han sido sometidas a un proceso de envejecimiento en laboratorio. La respuesta a largo plazo se ha comparado a través de los ensayos de módulo de rigidez y de fatiga. En los betunes recuperados se han llevado a cabo los ensayos de penetración y anillo-bola, así como el seguimiento del envejecimiento a través del análisis de infrarrojos. Finalmente, la distribución de peso molecular aparente (AMWD) de los betunes se ha calculado a través de medidas reológicas usando el "δ-method". En los resultados se observa una relación entre la evolución del envejecimiento y su respuesta mecánica, donde la tendencia general es similar para ambas técnicas.

Effects of Short-Term Ageing Temperature on Conventional and High-Temperature Properties of Paving-Grade Bitumen with Anti-Stripping and WMA Additives

“…Due to the aforementioned factors, increasing popularity of warm-mix asphalt techniques is seen, which created scientific interest in the properties and long-term durability of foamed mixtures. These properties of warm-mix asphalt mixtures, among other factors, are highly dependent on the composition, temperature, and aging history of bituminous binders [ 26 , 27 , 28 ]. Studies conducted during the construction of test sections using various warm-mix techniques [ 29 ] have shown that their utilization in many cases severely impacts the high-temperature grade of the asphalt binders extracted from the paved mixtures.…”

Applicability of time-temperature superposition for laboratory-aged neat and SBS-modified bitumens

“…However, these approaches are not easily linked to the effects of aging at the molecular level and a correlation between the microstructure and the physical response lacks a unique definition (2,5,13,(28)(29)(30). Despite this, rheological indicators (e.g., viscosity, linear and non-linear viscoelastic functions) have been used to substantiate results from compositional test methods to provide clear insights on the changes in bitumen microstructure and their effects on performance (3,(31)(32)(33)(34). In the case of PMBs, the rheological analysis becomes even more complicated since the response is affected by non-Newtonian effects, strain dependency, thixotropy, and uncertainties about the applicability of the time-temperature superposition principle (TTSP) (37)(38)(39)(40)(41)(42)(43)(44).…”

Effect of the recycling process and binder type on bituminous mixtures with 100% reclaimed asphalt pavement

“…Specifications regarding these can be found in many countries (Dinis-Almeida et al, 2012). Other processes are newer techniques that produce warm and half-warm recycled mixtures about which much research is being conducted to verify the properties of the resulting mixture (Romier et al, 2006;Gaudefroy et al, 2007;Dinis-Almeida and Lopes, 2015;Lopes et al, 2015;Lu et al, 2016;Mallick et al, 2008;Punith et al, 2012;Van de Ven et al, 2007;Pérez-Martínez et al, 2017).…”