• cement treated base
• comparison
• infrastructure
• lca
• life cycle assessment
• multi-criteria analysis
• weighting factors
• weighting methodology

The main objective of this study is to increase the capacity of the pavement community to make decisions regarding the construction, maintenance, and rehabilitation of transportation infrastructures that would ultimately enhance the sustainability of transportation systems.
This work is based on the primary data of an Italian construction company: Giuseppe Pesaresi Spa. The company has provided the data related to the recipes of the mixture, the laboratory test of them, the data of the building machines, and the data of the machine in the mixing plant.
The case study investigates the construction of a subbase layer in road contraction: Cement Tread Base (CTB). It consists of a uniform mixture of crushed aggregate, Portland Cement and water placed, compacted, and finished on the prepared surfaces. The purpose is to use the PSB methodology for ranking the different design alternatives and choosing the best environmentally friendly. The different alternatives of CTB are from different ways to produce it and different recipes that use also recycled materials.
The first step is a pavement design. The scope is to calculate the different thickness of the CTB using different recipes, with virgin aggregate and RAP. The analysis is conducted by keeping all input constant except the elastic modulus and the thickness of CTB. The purpose is to find the different thickness of the recipes to achieve the same performances in all pavement designs.
The second step is to estimate the potential environmental impacts related to the production of traditional cement treated base (CTB) mixed with virgin aggregate and cement treated recycled base (CTRB) mixed with different ratios of RAP and virgin aggregate. Furthermore, the study considers two different ways to produce CTB and CTRB: Mixed-in-Place Production (MPP) and Central Plant Production (CPP). The LCA methodology is used to estimate the potential environmental impacts of the road base layer production.
The last step is applying the weighting methodology for ranking the alternatives and choose most environmentally friendly.