Desenvolvimento e análise do desempenho de elementos de drenagem fabricados em concreto permeável

LAMB, G. S. Desenvolvimento e Análise do Desempenho de Elemento s de Drenagem Fabricados em Concreto Permeável. 2014. Dissertação (Mestrado em Engenharia Civil) – Programa de Pós-Graduação em Engenharia Civil, Univ ersidade Federal do Rio Grande do Sul, Porto Alegre. Many undesirable problems associated with the occur rence of floods and rapid flood peaks are common in Brazilian urban centers and are inten sifi d due to the increase of waterproofing of surfaces caused by the growth of c ities. An alternative to mitigate these problems is the use of draining pavements that allo w infiltration and collaborate with the delay of storm water runoff. Among the available op ti ns, pervious concrete has been attracting attention in recent years. This is a spe cial concrete made with selected particle size distribution (without coarse aggregate and particle s of similar dimensions) to generate a structure containing large connected pores, which w ould allow a fast and large percolation of fluids trough the material. Taking into account the different challenges associated with urban drainage, the research group at LEME has been inves t gating a new possibility for the use of pervious concrete as a constituent material of urba n stormwater drainage systems. It is well known that the major problem that affects this kind of systems is the obstruction of the openings by different materials, in addition to the d crease of water flow in the galleries because of the accumulation of material inside them , causing partial or total loss of flow capacity. The use of pervious concrete can enable t he passage of high flow rates, while constituting a barrier to the passage of debris and a atural water filter, preventing the entry of potentially granular material and solid waste parti cles inside the galleries of the drainage system. Seeking to contribute to the evaluation of this idea, the present work was designed focusing on the study of the use of pervious concre te for the manufacture of plate elements, which could be used to replace the grilles that are cu rently in use in sewers. In order to guide the study, the requirements of the Rain Sewage Depa rtment (Departamento de Esgotos Pluviais DEP) from Porto Alegre were taken as a r eference. After a preliminary study made to adjust and characterize the mix of pervious conc rete to be used, six plates prototypes were fabricated using a 1:4 (cement:sand) proportion, wi th s milar dimensions to the DEP grilles. These were then tested to check flexural capacity a nd permeability (of specimens cored from the plates). Also, using special devices created at LEME, the effects of rain and the passage of water carrying fine material in suspension were sim ulated, and the performance in terms of clogging of these elements was roughly assessed. Fo r comparison, a conventional grille currently made by DEP was also tested. The results from the mechanical strength and permeability tests indicated that the pervious plat es had superior performance when compared to the conventional grilles, indicating that studie s toward the production of drainage elements in pervious concrete are promising and should be co ntinued. The results from the clogging test however indicate that cleaning strategies may be necessary on the long run if fine material accumulates in the pores of the pervious concrete. Key-words: elements of drainage; urban drainage; pervious conc rete.