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LCA and cost comparative analysis of half-warm mix asphalts with varying degrees of RAP
Published in John Harvey, Imad L. Al-Qadi, Hasan Ozer, Gerardo Flintsch, Pavement, Roadway, and Bridge Life Cycle Assessment 2020, 2020
T. Mattinzioli, F. Moreno, M. Rubio, G. Martínez
With the mixtures designed, the HMA was produced in a fuel oil conventional discontinuous plant (batch asphalt plant), where the aggregates are weighted and measured, as specified, and heated to 180°C. The aggregates were then mixed with the bitumen and the filler at roughly 160°C in the pugmill. The production process for the HWMA was very similar to the manufacture of HMA in a conventional plant, but mixed at a lower production temperature (60-100°C) (Rubio et al., 2012); aggregate weighted and heated to 100°C, and mixed with the filler and bituminous emulsion at 60-70°C (Rubio et al., 2013). Because of the water in the HWMA bituminous emulsion, compactors require more passes to achieve optimal density (Rubio et al., 2013), therefore the compactors for the HWMA were assumed to pass 50% more than for the HMA mixture (HMA: 2-3 passes, HWMA: 5-6).
Influence of asphalt composition upon the thermodynamics performance of a mixing plant
Published in Road Materials and Pavement Design, 2018
F. Huchet, L. Le Guen, P. Richard, M. Piton, B. Cazacliu, P. Semelle, J. Matheus, H. Riche, P. Tamagny
For a decade, RAP has attracted strong environmental interest (Jullien, Monéron, Quanranta, & Gaillard, 2006), since 100% RAP mixture (Zaumanis, Mallick, & Franck, 2014) needs to be reached in the near future. Although pollutant emissions and economic assessment have been extensively studied, the energy/materials interaction in asphalt production has not been considered much. The realisation and the design of road pavement are complex. In its first stage, materials are manufactured in an asphalt plant involving the mixing of aggregates (i.e. sand, gravels and eventually RAP) and an organic binder of bituminous type. To achieve the mixture and, thus, obtain the workability required to spread the bituminous concrete, a high temperature is necessary to decrease the viscosity of the granular media (90°C < Tasphalt concrete < 160°C). Currently, a burner located within the inclined rotary drum supplies a combustion flame that releases the energy flux required for aggregates’ heating (see Figure 2). Thus, according to the kiln type, aggregates flow at co- or counter-flow with respect to the exhaust gases. The rotary kiln equipment is generally used for a thermal granular process and the building materials and their by-products contributes by a large amount to the global energy consumption (clinker: Utlu, Sogut, Hepbasli, & Oktay, 2006 – marble and asphalt materials: Chen, Yang, Tang, & Wang, 2007; Peinado, Vega de, Garcia-Hernando, & Marugan-Cruz, 2011). The evolution towards a circular economy is far from being completely accomplished and it depends on industrial renewal, especially the optimisation of recycling processes. In that context, the improvement and the advanced design of traditional materials and facilities are the key to reach a circular economy. For pavement materials, an optimum saving of resources, including energy resources (e.g. fuel and bitumen) during asphalt production is required to achieve that goal, and also to abide by new regulations. Few asphalt materials have already emerged such as Warm-mix Asphalt, made at TWMA ∼120°C (i.e. modified or not, by natural or polymeric additives to reach convenient handling) (Cazacliu et al., 2008) or bio-oil-based asphalt requiring also a low temperature treatment because of its sensitivity (Aziz, Rahman, Hainin, & Bakar, 2015). Fair sustainability depends also on their ability to be recycled.