Environmental impact of real precast and cast-in-situ supermarket building structures

Alongside the efforts focusing at material level to mitigate the environmental impact of constructions, another instrument is reduction of material volume by structural optimisation, often ensured by innovative technologies employing high-performance materials that typically have, assuming same material volume, higher impact than traditional ones. The present paper compares the environmental impact of two similar single-storey supermarket facilities designed and built in near areas of the Po valley, Northern Italy, with precast or cast-in-situ concrete. Analysing the bill of materials employed for the uncladded superstructure of both buildings, the comparison based on several environmental impact indexes derived from Environmental Product Declarations, computed per covered square metre, allows to evaluate and compare the impact of the two structural solutions concerning the use of raw materials. Despite using materials with higher footprint, the precast solution allows a global reduction of all the environmental indexes, equal to 44% in terms of global warming potential, thanks to structural optimisation allowed by such materials used in combination with advanced batching and moulding technologies. The theoretical replacement of most impacting components with alternative more sustainable solutions shows single improvements of 13–20%, which despite being relevant, is less effective than structural optimisation in tackling a consistent reduction of impact.