Contents lists available at ScienceDirect Resources, Conservation & Recycling journal homepage: www.elsevier.com/locate/resconrec Full length article Is gravel becoming scarce? Evaluating the local criticality of construction aggregates Dimitra Ioannidou a, ⁎ , Grégoire Meylan b , Guido Sonnemann c,d , Guillaume Habert e a Chair of Sustainable Construction, ETH Zurich. Stefano-Franscini-Platz 5, 8093, Zurich, Switzerland b Transdisciplinarity Lab, Department of Environmental Systems Science, ETH Zurich, Universitaetstrasse 22, 8092 Zurich, Switzerland c Univ. Bordeaux, ISM, UMR 5255, F-33400 Talence, France d CNRS, ISM, UMR 5255, F-33400 Talence, France e Chair of Sustainable Construction, ETH Zurich. Stefano-Franscini-Platz 5, 8093, Zurich, Switzerland ARTICLE INFO Keywords: Aggregates Criticality Supply risk Locality ABSTRACT Natural aggregates are considered an immense natural resource at the global level; however some regions face a supply constraint due to the overexploitation of natural aggregates in construction. This paper presents an as- sessment of the local criticality of quarried aggregates by adapting the methodology for metal criticality de- termination to the characteristics of construction aggregates. Two approaches, strong and weak locality, are envisaged to examine different substitution scenarios in the case of local supply constraint. The adapted methodology examines three dimensions: Supply Risk, Environmental Implications and Vulnerability to Supply Restriction. The application of the methodology to the cantons of Switzerland shows that inside a country, the criticality is driven by the Supply Risk, which depends on the surface and number of quarries and their dis- tribution in the region. A comparison of the supply risk of aggregates with the supply risk of steel shows that for most of the cantons the supply risk of natural aggregates is lower. The application of this methodology at a world scale will indicate highly critical regions and enable policymakers to define measures for ensuring a sustainable growth, either by regulating the extraction of aggregates or by demonstrating the local need to consider the use of other materials, apart from concrete. 1. Introduction The current fast pace of technological development and the in- creasing demands of the economy lead to a soaring consumption of energy and resources. The modern trend of energy efficiency in the building sector is on the one hand making buildings self-sufficient with respect to energy, but on the other hand comes at a cost of huge ma- terial investments (Rovers, 2014; Horvath, 2004). Among the resources used in construction, one of the major categories in terms of volume are natural aggregates, namely crushed rock, natural gravel and sand. “Aggregates are essential and valuable resources for the economic and social development of humankind” (Blengini et al., 2012).Natural ag- gregates are used in the production of portland cement and as a com- ponent of portland cement concrete and asphalt concrete (Horvath, 2004). Stone reserves are considered infinite at the global scale, however at a regional level they can face a supply constraint and potentially lead to critical situations (Habert et al., 2010). This situation is especially observed in many parts of the world, such as Dubai and Singapore, where the construction industry is booming and construction resources are overexploited (UNEP, 2014). It is, therefore, desirable to evaluate locally the criticality of construction aggregates in order to facilitate decision-making and regional planning (Agioutantis et al., 2014) and the adoption of policies to prevent critical situations in regional building sectors. Criticality as a concept refers both to a high potential impact of shortage (when the resource is particularly important for the value chain and has few or no substitutes) and to a comparatively high probability of such a shortage (Buijs et al., 2012; National Research Council, 2008; European Commission, 2011; Jin et al., 2016). The criticality assessment of minerals integrates environmental, socio-eco- nomic and geopolitical aspects related to the availability and use of minerals (Sonnemann et al., 2015; Drielsma et al., 2016). Both the United States National Research Council (2008) and the European Commission (2010) have published studies on the criticality of various metals. One of the most widely discussed criticality methodologies http://dx.doi.org/10.1016/j.resconrec.2017.07.016 Received 5 December 2016; Received in revised form 11 July 2017; Accepted 11 July 2017 ⁎ Corresponding author at: ETH Zurich HIL F 28.2, IBI, Stefano-Franscini-Platz 5, 8093, Zurich, Switzerland. E-mail addresses: ioannidou@ibi.baug.ethz.ch (D. Ioannidou), g.meylan@usys.ethz.ch (G. Meylan), guido.sonnemann@u-bordeaux.fr (G. Sonnemann), habert@ibi.baug.ethz.ch (G. Habert). Resources, Conservation & Recycling 126 (2017) 25–33 0921-3449/ © 2017 Elsevier B.V. All rights reserved. MARK