Download Sustainability Concepts Applied to the Design of Recycled Aggregates Concrete Book in PDF, Epub and Kindle
Due to the related problems and the ongoing awareness on environmental issues is that efforts are put in different areas of knowledge, in order to determine, analyze and formulate solutions towards a sustainable future. Among these problems, there are the ones related with the use of concrete in the construction sector. These are essentially related to the natural resources used for their production and to the manufacture of cement, one of its most important components. As of today, one of the solutions is recycling the concrete for the production of aggregates, which can be used in the elaboration of new concrete mixes. This is in fact not the best solution as, albeit the natural aggregates utilization is reduced and consequently the depletion of natural resources is as well, more quantities of cement are needed to achieve comparable properties to those of the natural aggregates concretes, being cement a relevant contributor to global warming. A novel method for recycled aggregates concrete design, so-called ¿Equivalent Mortar Volume¿, aims on solving the aforementioned issues by basing its principles on the idea that recycled aggregates are materials that are composed by two phases, the natural aggregate and the attached mortar to it, and by taking into account the attached mortar as part of the new mortar required by design in the concrete mix. With this, the needs for cement are reduced while still using recycled aggregates and achieving similar properties to those of the natural aggregates concretes. The method always starts from a concrete design made with the American Concrete Institute method as a base. The novel essence of the method encourages to investigate more about its properties and the possibilities to broaden its scope, for which the present doctoral thesis is proposed. On a initial stage, the Equivalent Mortar Volume method is studied and an adaptation of it is proposed in order to broaden its scope by making it able to start with other design methodology than the American Concrete Institute one. This is achieved by designing different concrete mixes and by analyzing the different calculation steps that the method involves. From the work carried out, it is concluded that the method represents a feasible and environmentally friendly solution, and that it can be adapted to another concrete design methodology. The next stage consists on the obtention and analysis of some of the fresh state, mechanical and durability properties of the different concretes, and to evaluate the use of different methodologies for the concretes design. This was achieved by elaborating extensive experimental campaigns of different concretes mixes and by assessing them when appropiate. The findings of these campaigns show that the concretes designed with the novel method achieve, in the majority of the studied properties, comparable results to those of the natural aggregates concretes. In the following stage, the rheological properties of the concretes are studied by means of a viscometer apparatus. This was done with the aim of having a deeper understanding of some of the properties that the method affects the most. It was observed that the concretes designed with the novel method can achieve similar rheological properties to those of the natural aggregates concretes, when combining the use of certain admixtures.