LCA di pavimentazioni stradali flessibili in conglomerato bituminoso : strategie di miglioramento delle prestazioni ambientali

In Italy, 28 million tonnes of asphalt has been produced by about 650 plants in 2011, and 11 million of reclaimed asphalt pavement (RAP) has been produced by milling old pavements. However, recycling rate of RAP is only 20%, a low value compared to other European countries (EAPA, 2012). Moreover, total production of asphalt in Italy is made using the traditional hot method, while techniques to reduce temperature production are emerging in Europe. Increasing the amount of RAP and, by the other hand, using WMA techniques is a good way to reduce environmental impacts of asphalt pavements during their lifecycle. This work has been carried out in collaboration with Impresa Bacchi s.r.l., and it’s finalized in finding out how much the environmental benefits are producing asphalt pavements with a major percentage of RAP and using WMA. One virgin pavement (no RAP + HMA) has been taken as a baseline, and two more sustainable pavements are compared with it. All the stages of the lifecycle has been considered, from extraction of virgin materials to end of life. The results show that extraction and production of virgin materials have the higher impacts in the lifecycle, mainly due to the presence of bitumen, a petroleum derivative which has high impacts during its production. Increasing usage of RAP means decreasing use virgin material and bitumen, and this has benefits in terms of CO2eq emitted and other indicators. Combining usage of RAP and WMA has extra benefits: CO2 emissions are reduced by 11,9 % with respect to the virgin pavement during its lifecycle. All the other indicators studied show a reduction of impacts moving from a totally virgin-asphalt pavement to a pavement made with RAP and WMA. Impacts from electricity consumption of the asphalt plant are slightly higher for the pavement with higher content of RAP, due to higher electricity consumption for RAP sieving, but this is significantly smaller than benefit of recycling. A comparison between impacts from lifecycle of pavement and emission of vehicles has been made: results show that for a high traffic volume (>1000 vehicles/hour), impacts from lifecycle are negligible compared to impacts from vehicles.