ABSTRACT
In the present global health emergency, face masks, gowns, caps, gloves play a key role in limiting the diffusion of the COVID-19 pandemic, by acting as physical barriers to avoid droplets and filtrate exhalations coming from infected subjects. Since the most widespread devices are disposable products made of plastic or rubber materials, this means that relevant quantities of fossil resources are consumed, and huge amounts of wastes are generated. Currently the end of life of personal protective equipment (PPE) represents a problem in environmental, economic, and social terms. The market considers two possible disposal scenarios: incineration with energy recovery or landfill. In both cases, significant impacts are achieved both on the environment and on human health. This study aims to propose and validate a new scenario for PPE based on material reuse for bituminous conglomerates. The Life Cycle Assessment methodology and the experimental tests has been used to assess the environmental impacts in terms of both ReCiPe midpoints and endpoints and for demonstrate the technical feasibility of this new scenario. From an environmental point of view, relevant benefits were observed in comparison with the standard incineration for energy recovery or disposal in landfill.
ABSTRACT
Due to the COVID-19 pandemic, global personal protective equipment (PPE) volume production and demand increased by 300-400% between 2019 and 2021. In this scenario, the present study aims to propose and validate an innovative circular economy scenario for end of life (EoL) PPEs, reusing them to produce reinforced bituminous mixtures. Despite that several studies confirmed the possibility of reusing plastic in the asphalt mixtures, none of them investigated the potential of PPEs, highlighting the innovativeness in the scientific panorama. Five different alternatives of EoL PPE mixtures (different products, materials, dosages, etc.) were tested at laboratory scale to verify the technical feasibility of the proposed scenario. The most promising solution resulted to be the mix of gloves and face masks composed by polypropylene, polyethylene, nitrile and lattice at a dosage of 0,5% weight/weight that allowed to produce bituminous mixtures with acceptable performances in terms of relevant mechanical parameters while recycling waste PPEs. This leads to environmental benefits, since more than 3kg of EoL PPEs per square meter of road pavement can be reused instead of disposed (about 1,5 million tons/year considering the bituminous mixtures produced at European level), as well as economic benefits for public administrations and the collectivity, due to the reduced landfilling of solid wastes.
ABSTRACT
In recent years, both dry and wet processes to include waste rubber (WR) in bituminous mixtures have had little success in Italy due to technical and economic reasons. However, the necessity to recycle this waste material and the increasing interest in low-noise emitting pavement is encouraging researchers and stakeholders to explore new solutions. In this context, a hot-mix asphalt (HMA) manufactured with polymer-modified bitumen and fine WR added through a dry method has been recently developed. This paper deals with the rheological characterization and modeling of this innovative HMA, in comparison with two reference mixtures, with ordinary polymer-modified bitumen and with an asphalt rubber binder produced through a wet process. The complex modulus was measured through uniaxial cyclic compression tests at different temperatures and frequencies. The Huet-Sayegh rheological model was used to simulate the experimental data. The results showed that the time-temperature superposition principle is valid, despite the presence of polymers and WR. The Huet-Sayegh model allows a good fitting of the dynamic modulus and loss angle data to be achieved. The viscous response of the mixture including polymer-modified bitumen and rubber powder is higher than the other HMAs, which is mainly associated with the nature of the modifiers, the binder content in the mix and the less severe short-term aging.
