Estudo do potencial de aplicação de resíduo de concreto em substituição ao agregado graúdo para concretos permeáveis

Abstract

The search for environmental preservation and conservation of natural resources, motivated by the activities harmful to the environment associated with the construction industry, makes new concepts and technical solutions viable for sustainable development. The genesis of the present work derives precisely from the lack of financial resources that characterize the current economic situation of brazilian universities, together with the growing demand for repairs in the Federal University of Juiz de Fora buildings: to use the large amount of concrete waste generated and deposited in areas of the Campus replacing natural aggregates in the production of pervious concrete, which, in turn, represents an excellent artifice in the fight against the phenomenon of urban surface waterproofing. There are numerous benefits of using permeable coatings in paving: reduce runoff; temporarily storing the surplus water, relieving the drainage system; to feed the underground aquifer and recover the soil filtration capacity; in addition to presenting lower life cycle cost in detriment to other conventional materials. This research involves the pioneering assessment about the influence of the use of these recycled waste in replacement to 100% of the conventional aggregate of stone origin in the mechanical and hydraulic behavior of the pervious concrete by means of tests recommended by ABNT NBR 16416: 2015, without the use of additives. For that, a dosage study was carried out to determine the most suitable trait for the preparation of the drainage composite as a floor, and it was hoped to obtain a material in accordance with the normative requirements of resistance and permeability, from technically feasible procedures. All the permeability coefficients obtained in the laboratory exceeded the normative limit of 0.1 cm/s, reaching values of up to 2.36 cm/s. Likewise, average compressive strength values of the test pieces close to the limit of 20 MPa stipulated by the standard (23.98 MPa and 19.57 MPa for 60 mm and 80 mm pieces respectively) were obtained and the flexural tensile strength was also observed: mean of 2.08 MPa, higher than the recommended minimum (2 MPa). In view of the favorable outlook, the final products can be manufactured in series by the institution and used in the maintenance of the Campus areas, directly and indirectly reducing the expenses associated with the construction waste and the waterproofing of the urban pavements.