## 7 Conclusions  
The present study has been carried out with the aim of developing a tool for monitoring the environmental impact resulting from pavement maintenance works. The study was based on a certified methodology for measuring environmental impact that ensures the repeatability and quality of the results. As shown in the work, EPD certifications make it possible to take into account all the variables involved, including future benefits obtained from new production technologies, eco-friendly materials, and other future aspects that may affect the environmental impact of pavement maintenance. In general, the EPD certification contains a detailed list of information related to the environmental impact of the production processes used to manufacture a given product. On the other hand, the calculation process illustrated in the work starts from this list of values and leads to the definition of a synthetic index that can be more easily implemented within Pavement management tools. It should be borne in mind that while EPD certification is standardized for any type of product, the process of calculating the EAR index is specific to asphalt mixes and that, therefore, the standardization values, as well as the choice of weights, have been determined on the basis of the specific production process. The developed methodology also allows for the evaluation of environmental performance as a function of mechanical performance: the application of performance multipliers, defined in Section 5.2 is intended to ensure a \"performance parity\" evaluation and thus to assess the impact associated with the effective useful life of the material. The EAR index can be applied at different stages of maintenance:  
* Design stage of maintenance operations: the impact is calculated from the quantities and types of asphalt concrete planned in the project. At this stage, the \(EAR_{\mathrm{c}}\) index considered is the maximum derived from the analysis of the mixture authorized and therefore takes the name \"Potential Impact\". * The \(EAR_{\mathrm{c}}\) index can be used as a reward criterion for awarding scores to the bids of competitors in tenders. The calculation of the index may be made on the basis of EPD certifications submitted by the contractor for each proposed mixture and on the basis of the location of the facilities on the territory, i.e., the average distance of the construction site from the facility. The score for each individual bid may be awarded according to the decrease in the EAR index compared to the potential impact described in the previous point. * In the monitoring phase: the index may be recalculated based on data obtained from the execution of works and material control. Figure 3: Comparison of \(EAR\) and \(EAR_{\mathrm{c}}\) values evaluated for the four reference mixtures. The results derived from the considered EPD certifications show values of the EAR index ranging from a minimum of 31.42 to a maximum of 78.95. For each EAR value, the impact in terms of emissions (Category A), resource consumption (Category B), and reuse potential (Category C) has been quantified. As discussed in Section 5.1, the most decisive contribution is given by Category A. This is also because of the combination of weights adopted among the three categories discussed in Section 5.1. Further considerations concern the impacts due to the different phases of the asphalt production and paving cycle: in all cases examined, the greatest impact is due to the raw material production phase (phase A1) followed, respectively, by the impact of in-plant production (phase A3) and transportation for raw material procurement (phase A2). The lowest impact is due to the transport and paving phase at the site (phases A4 and A5). Finally, the application of performance coefficients ensured the effective differentiation between mixtures. This is of paramount importance in order to be able to guarantee that the quantification of the environmental impact is effectively related to the performance of the mixtures.