Abstract
Growing awareness about preservation of the environment has led asphalt technicians to assess and correct resulting impacts from the manufacture and application of bituminous mixtures. The concept of sustainability has come to the field of bituminous mixtures with two main components: reducing emissions and consumption of raw materials and preserving resources for the future. Conservation and rehabilitation activities of road pavements generate an increasing amount of waste from the milling of layers of damaged asphalt mixtures. This material, having great costs and exceptional properties, should be reused in manufacturing new mixtures of the same type and function. This paper presents efforts carried out to develop a technology allowing manufacturing and applying half-warm mix asphalt in surface layers of low-speed roads at low temperatures by using high percentages of reclaimed asphalt pavement. Continuously graded mixtures were manufactured at 100°C and compacted at 80°C with different percentages of RAP, from 50% to 100%. Results obtained from testing laboratory specimens indicated that their mechanical properties, cracking resistance and fatigue resistance, were close to those expected from regular hot-mix asphalt mixtures. Additionally, a field study was carried out in which this technology was put to use. First field cores were extracted and tested from old pavement and then the RAP coming from this pavement was employed to manufacture laboratory specimens with different gradations, RAPs, and emulsion contents. Results showed that use of this technology provided the new mixture with improved fracture properties and ductility with respect to the old pavement mixture.
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