Estimación del uso de agua en el proceso de lavado de agregados pétreos y planteamiento de un sistema de reutilización del agua en el laboratorio. Caso de estudio: diseño y control de calidad de mezclas de concreto asfáltico

Abstract

Water is a vital resource for society, since much of daily human life depends completely on its availability (Lamma, Warner, Lundy, Bommidi, & Beattie, 2018), and it is for this reason that the global demand for Water over the last decade has steadily increased at a rate that exceeds supply sources (Hobbs, Anda, & Bahri, 2019). According to the United States National Intelligence Council (US NIC, 2012), it is estimated that by 2030 the demand for water will increase by 40%. On the other hand, according to the United National World Water Assessment Program (2016), approximately 1.35 billion jobs (corresponding to 42% of the entire active workforce in the world) largely depend on water use (Lamma, Warner , Lundy, Bommidi, & Beattie, 2018). For this reason, it is vitally important to avoid the waste of this resource, and thus contribute to its sustainability and conservation for future generations. On the other hand, most of the pavement structures that are designed and built in Colombia and in the world are of the flexible type or have treads or surfaces built with asphalt layers, being more than 90% of the roads built in the world. and more than 65% of the roads in Bogotá (Rondón & Reyes, 2015). During the construction of flexible pavements, large quantities of stone aggregates are used, whose characteristics must be more demanding in terms of durability, texture and mechanical resistance in those that make up the asphalt mixtures. To carry out said characterization and evaluate correct compliance with the minimum quality requirements required by the Colombian specifications of the National Road Institute – INVIAS (2013) and the Urban Development Institute – IDU (2011), the aggregates must be subjected to laboratory. These tests are carried out to measure physical parameters of the aggregates, such as specific gravity, and to evaluate their quality from the point of view of their mechanical and abrasion resistance, their shape or geometry, cleanliness, among other aspects. Most of these tests require a priori the washing of the stone aggregates with water, which consists of separating and eliminating the finer particles (particles with a size less than 0.075 mm) from the coarse ones. This practice obviously forces the consumption and waste of large amounts of water during the execution of the tests. For this reason, it is imperative to estimate the water waste generated during stone aggregate washing processes in laboratory tests, as well as identify and plan the necessary strategies for its most efficient and sustainable use in the short and long term. Stone aggregates are materials found in all layers of flexible pavement. However, to limit the scope in this study, the impact generated by the washing of said materials during the construction of asphalt layers with asphalt concrete mixtures will be evaluated. This type of mixtures were chosen because they are the most used in Colombia for the formation of asphalt layers in road structures. The construction of asphalt layers refers to all the stages necessary to carry out the installation of the asphalt concrete mixture, that is, it includes the stages of design, manufacturing, transportation, extension, compaction and quality control.