Design of field trial with stabilized granular mixtures containing recycled aggregate from construction and demolition waste

In recent years, growing attention has been paid to the recovery of construction and demolition waste. Public authorities are encouraging the recycling of this waste by converting it into aggregates. Construction and demolition waste (CDW) aggregates can replace traditional aggregates in many applications, in order to increase the environmental sustainability of the construction industry by reducing the number of new landfills and saving valuable natural resources. In pavement construction, CDW is already used for embankment and subgrade formation. As with natural aggregates, the mechanical properties of CDW can also be improved through stabilization, so that its use in the subbase layer of pavements can also be envisaged. Although the effectiveness of CDW stabilization has already been demonstrated, this practice is not yet common. In addition, applications of stabilized CDW aggregates involve the use of traditional Portland cement, whose production cycle is recognized as being highly impactful from an environmental point of view. The research developed in this master thesis is part of the INTREC project (Innovative technologies for recycled aggregates from construction and demolition waste in road construction), whose aim was to develop sustainable recycled materials for the formation of subgrade layers. In particular, in this study new cements and stabilizing agents have been investigated with the aim of obtaining stabilized granular materials suitable for full-scale applications. The materials of this study include both unbound and stabilized as well as stabilized ones using both traditional and non-traditional binders. The research was developed in two distinct phases, (i) the laboratory study and (ii) the design of field testing. In the first phase, the unbound and stabilized mixtures were optimized by means of the Proctor method. Such optimized mixtures were subjected to mechanical characterization, which included resilient modulus and strength tests. The most promising mixtures were then considered for the second part of the study. The construction of the road test which will be located in La Loggia (South of Torino) will include a subbase layer made up of the materials selected in phase 1, including both granular and cement stabilized mixtures with natural aggregates as experimental references, and mixtures containing the innovative binders. The purpose of the field test is to assess the behaviour of materials in a road segment that will operate under severe traffic conditions. In this study, the field test project includes: (i) the pavement design, (ii) the construction programme, (iii) the scheduling of testing activities (both in the field and in the lab), and (iv) the estimation of material quantities required for construction. In this thesis, some preliminary activities aimed at the implementation of field tests through a light-weight deflectometer (LWD) were also carried out.