Paving with Precast Concrete Made with Recycled Mixed Ceramic Aggregates: A Viable Technical Option for the Valorization of Construction and Demolition Wastes (CDW)

Abstract

materialsArticle Paving with Precast Concrete Made with Recycled Mixed Ceramic Aggregates: A Viable Technical Option for the Valorization of Construction and Demolition Wastes (CDW) Andrés Juan-Valdés 1,* , Julia García-González 2, Desirée Rodríguez-Robles 3, Manuel Ignacio Guerra-Romero 1, Fernando López Gayarre 4, Nele De Belie 5 and Julia M. Morán-del Pozo 1 1 Department of Agricultural Engineering and Sciencies, University of León, 24071 León, Spain; ignacio.guerra@unileon.es (M.I.G.-R.); julia.moran@unileon.es (J.M.M.-d.P.) 2 Department of Agriculture and Feeding, University of La Rioja, 26006 Logroño, Spain; julia.garciag@unirioja.es 3 Department of Agronomy and Forestry Engineering, University of Extremadura, 06007 Badajoz, Spain; desireerodriguez@unex.es 4 Department of Construction, Campus de Gijón, University of Oviedo, 33203 Gijón, Spain; gayarre@uniovi.es 5 Magnel Laboratory for Concrete Research, Ghent University, 9052 Ghent, Belgium; Nele.DeBelie@ugent.be * Correspondence: andres.juan@unileon.es; Tel.: +34-987-291000 Received: 4 December 2018; Accepted: 18 December 2018; Published: 21 December 2018

Abstract: This research aimed to prove the feasibility of producing two types of precast elements widely used in construction, such as curbstones and paving blocks, using recycled concrete made with a 50% substitution of the natural gravel by recycled mixed aggregates with a significant ceramic content (>30%). In order to prove the quality of such mass concrete recycled precast elements, two different mixes were used: the first one was a conventional concrete mix provided by Prefabricados de Hormigón Pavimentos Páramo S.L., one of the collaborating companies in this study, and the other was a mixture in which wt 50% of the natural coarse aggregates were substituted for recycled mixed aggregates ceramic (RMAc). This recycled aggregate is a heterogeneous mixture of unbound aggregates, concrete, ceramic, etc., used as a secondary recycled aggregate and commonly produced in a lot of recycling plants in many European countries. This material was supplied by Tecnología y Reciclado S.L., the other collaborating company. Both mixtures were representative in order to establish the comparative behavior between them, taking into account that smaller percentages of replacement of the natural with recycled aggregates will also produce good results. This percentage of substitution represents a high saving of natural resources (gravel) and maintains a balanced behavior of the recycled concrete, so this new material can be considered to be a viable and reliable option for precast mass concrete paving elements. The characterization of the recycled precast elements, covering mechanical, microstructural, and durability properties, showed mostly similar behavior when compared to the analogous industrially-produced pieces made with conventional concrete.