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Different ways of using oxygen enrichers have been studied. First, the performances of two different devices were tested: the results were very similar to the constructors' previsions. Second, oxygen concentrations in venturi masks connected to enrichers were measured with a mass spectrometer. The authors suggest to adjust the flow delivered by enrichers at 3 liters/min for any type of venturi mask. Pharyngeal oxygen concentration curves show the reliability of masks connected to enrichers compared to other modes of administration (nasal cannulae, nasal catheter).

The interest in using bio-materials in pavement engineering has grown significantly over the last decades due to environmental concerns about the use of non-recoverable natural resources. In this paper, bio-materials are used together with Reclaimed Asphalt (RA) to restore some of the properties of the aged bitumen present in mixtures with high RA content. For this purpose, two bio-materials are studied and compared to conventional and polymer modified bitumens. Blends of these materials with RA bitumen were produced and studied to simulate a 50% RA mixture. The rejuvenating effect of the two bio-materials on RA has been assessed and compared with the effect of the conventional binders. Apparent Molecular Weight Distribution of the samples (obtained by the ?-method) and different rheological parameters were used for this purpose. Results revealed the power of bio-materials to rejuvenate RA bitumen, showing their capability to be used as fresh binders in high-RA content mixtures., El interés en la utilización de bio-materiales en ingeniería de pavimentos ha crecido significantemente en las últimas décadas debido a la conciencia ambiental sobre el uso de recursos naturales no renovables. En este artículo, se utilizan bio-materiales para recuperar las propiedades iniciales del betún envejecido presente en mezclas con alto contenido de asfalto reciclado (RA). Para ello, se ha estudiado y comparado el comportamiento de dos bio-materiales con betunes convencionales y betunes modificados con polímeros. Con este objetivo, se fabricaron mezclas de bio-materiales y betún reciclado simulando mezclas asfálticas con 50% de contenido de reciclado. El efecto rejuvenecedor de los bio-materiales se ha evaluado y comparado con el efecto rejuvenecedor de ligantes convencionales mediante el cálculo de las distribuciones de peso molecular aparente y diferentes parámetro reológicos. Los resultados muestran el poder rejuvenecedor de los bio-materiales, poniendo de manifiesto su potencial para usarse como ligantes vírgenes en mezclas asfálticas con alto contenido de reciclado.

The current need to move towards more sustainable technologies in the construction sector has promoted the investigation of using alternative materials in asphalt mixtures for pavements. Biomaterials, used as biobinders, have shown their potential as partial replacement of bitumen in asphalt mixtures as solution to decreasing the demand for fossil-fuel-based binders as well as CO2 emissions. However, more research is needed to increase the replacement of bitumen in asphalt mixtures. In this investigation,biobinders are used as full replacement of virgin bitumen and as recycling agent within asphalt mixtures with high Reclaimed Asphalt (RA) content. Blends of biobinders and RA binders, and bio-recycled asphalt mixtures, were produced, subjected to ageing and rheologically characterised. The results show that the rheological properties of binders’ blends seem adequate for their use, while the bio-recycled asphalt mixtures seem to have a faster ageing than conventional ones, hence their full-scale application still remains a concern.

The present paper describes the rutting behavior of innovative mixes incorporating 50% of Reclaimed Asphalt (RA) with bio-materials. They were assessed in the laboratory and in a full-scale accelerated experiment. The innovative mixes studied here contained bio-materials especially designed to help recycling by re-activating the aged binder from RA. Four mixes were evaluated: three of them are manufactured with bio-materials, (two bio-rejuvenators and one bio-binder) and one was a control mix, which was a high modulus asphalt mix (EME2). In this study, the rutting resistance of the four mixes was first evaluated in the laboratory with both European and US methods. The full-scale test was then performed in order to evaluate the rutting resistance of the bio-recycled asphalt mixes under heavy traffic (200,000load cycles loaded at 65kN) and compared with the control one. A simplified analysis leads to the conclusion that, with the Nantes climate, a daily traffic of 150heavy vehicles per day applied over 20years corresponds to approximately 200,000heavy vehicle loads when the surface temperature exceeds 30°C. Therefore, it can be considered that the rutting evaluation made on the carrousel represented almost 20years of traffic during hot-day periods. The results obtained on the test track were consistent with the laboratory rutting tests showing good performance for all the mixes. The materials presenting the best performance on the test track also presented the best performance in the laboratory.

The present paper describes the full-scale accelerated test, carried out on asphalt pavements made up with bio-materials, especially designed to help reusing Reclaimed Asphalt (RA) by re-activating the aged binder. Four pavement sections were evaluated: three pavement sections with innovative bio-materials (bio-recycled asphalt mixtures), and a reference section with a conventional, high modulus asphalt mix (EME2). In this study, fatigue resistance was first evaluated in laboratory, with two-points bending test, and then at full scale under heavy traffic loading, with the IFSTTAR accelerated pavement testing facility. The evolution of bio-materials recycled asphalt mixture characteristics, as well as the pavement distresses, were recorded and analyzed. The structural condition of the pavement sections was monitored periodically through falling weight deflectometer (FWD) measurement as well as with strain gauges and temperature sensors. Although the reference EME2 mix presented the highest fatigue resistance in laboratory, on the full scale test, the three bio-based asphalt mixtures performed similarly or better than the control EME2 mixture.