Durability of hot and warm asphalt mixtures containing high rates of reclaimed asphalt at laboratory scale

Abstract

Within the framework of a sustainable development, manufacturing bituminous mixtures while reducing energy and using less new aggregates and new bitumen may be considered as an important topic, according to the quantities of asphalts mixtures produced for creating and maintaining road networks. This work aims to study the interest and the potential problems when coupling the warm mix asphalt technology (WMA) and the use of high ratio of reclaimed asphalt pavement (RAP) in the mixture. Initially, a study on managing RAP is performed, aiming to show that separating RAP aggregates in several fractions leads to a higher control of RAP in terms of homogeneity. Homogeneity of RAP is a key point for increasing recycling rates. The present study coupling WMA and RAP is based on the French design method for manufacturing asphalt concretes, which includes gyratory compaction tests, French wheel tracking tests, complex modulus tests and fatigue tests. However, the French design method does not take into account the physical and chemical aging of bituminous mixtures with time. As we consider that coupling WMA and RAP may lead to aging problems, it was decided to use an aging process before performing the standard tests. The results show that a WMA containing a high ratio of RAP has good performances according to the standard relative to this material, whatever the test. However, this material tends to be more sensitive to fatigue than hot and warm mixes without RA

Dosagem de mistura asfáltica com CAP 50/70 modificado com borra de petróleo

“…A Figura 2 mostra a distribuição granulométrica dos agregados minerais utilizados na obtenção das misturas asfálticas e a curva teórica da faixa C-DNIT obtida segundo as normas DNIT-ES 031/2006 e DNER-ME 035/95 [21,24]. A definição da composição granulométrica na mistura asfáltica é feita por meio de ajustes quantitativos dos agregados que consiste na escolha da distribuição granulométrica para uma estrutura de agregados adequada ao uso desejado, garantindo maior empacotamento entre as partículas [27,28,29]. Para este estudo, optou-se por uma composição de mistura de agregado com 40% de brita, 30% de pó de pedra, 25% de areia e 5% de cimento Portland como material de enchimento, que comparativamente à curva da faixa C-DNIT [21], Figura 2, apresenta uma graduação granulométrica descontínua, na qual se buscou proporcionar com a grande concentração de finos um esqueleto mineral com poucos vazios e o agregado graúdo contribuindo para resistência à deformação permanente [30].…”

Sustainability Assessment of Green Asphalt Mixtures: A Review

“…Additionally, in the literature, there is an inconsistency about the percentage of actual blending between RAP and virgin binders. For example, although some studies have accepted a complete mixing of aged and virgin binder [76,86,87] others have considered partial mixing between them [80,88,89]. Therefore, it is highly recommended to keep usage of RAP in the recycled mixtures to relatively low values due to inability to accurately characterize combined binder properties of recycled mixtures.…”

Effects of Ageing on Warm Mix Asphalts with High Rates of Reclaimed Asphalt Pavement

“…RAP incorporation was previously prepared by splitting in 4 fractions the material for then being recomposed in order to assure the same granulometry in all mixtures, with and without RAP (Lopes et al 2014).…”