Pervious pavements in car parks and driveways reduce peak discharge and the volume of runoff flowing in to urban drains and improve the water quality by trapping the sediments in the infiltrated water. This reduces the risk of pollutants such as suspended solids and particle bound chemicals such as phosphorous, nitrogen, heavy metals and oils and hydrocarbons entering receiving waters. The key objectives of the study are to establish relationships between rainfall and pervious pavement runoff and quantify improvements to infiltrated stormwater quality through the pervious pavement. The field experimental results were used to calibrate the PCSWMMPP model and to develop water flow and quality improvement transfer functions of the MUSIC model for concrete block and turf cell pavements. The research reported herein has demonstrated that pervious pavements can be introduced as a sustainable stormwater management initiative and as a key Water Sensitive Urban Design feature to deliver numerous benefits to the environment. The outcomes from the study will be useful in designing environmentally friendly car parks, pedestrian paths, light traffic drive ways, sporting grounds and public areas in the future. Land developers and local government authorities will be major beneficiaries of the study which has increased the understanding of the use of pervious pavements and explored a number of issues that previously inhibited the wider use of pervious pavements in practice.

Each of the studies conducted herein is related to best management practices for stormwater pollutant removal. This thesis is divided into two chapters. Chapter One details the development and functionality of a novel stormwater detention pond outlet, the solid state skimmer. The device is a perforated riser having no moving parts that is capable of draining detention ponds primarily from the topmost orifices. We found that such a device is capable of reducing effluent turbidity and sediment concentrations compared to a traditional riser outlet. Chapter Two describes a water quality monitoring study performed to show that a pervious concrete detention system can remove stormwater pollutants from parking lot runoff. The stormwater flowed across asphalt paving before infiltrating into the pervious concrete and an aggregate sub-base below. We sampled the runoff before it entered the pervious and after it passed through the detention system and found significant decreases in several pollutants.

Pervious concrete pavement has the capacity to perform as two types of infrastructure: a pavement; and a stormwater management solution. It is a low impact development as it does not alter the natural hydrological cycle when implemented, unlike a conventional impermeable pavement. This research represents some of the initial investigations into pervious concrete pavement in Canada. The two research hypotheses of this research were the following: 1. Pervious concrete pavement can be successfully planned, designed, constructed and maintained in Canada for successful performance based on surface evaluations of permeability rate and surface condition. 2. Verification that the subsurface drainage capabilities of pervious concrete pavement are as described in literature and can be quantified using instrumentation. Through monitoring of the design, construction, performance and maintenance of five field sites across Canada and various laboratory pavement slabs, the behaviour of pervious concrete pavement in freeze-thaw conditions has been evaluated. This thesis presents the findings from the various phases of the life cycle of pervious concrete pavement: planning; design; construction; and maintenance. An interpretation of the performance of pervious concrete pavement both from the perspective of the surface and subsurface is included. The various field sites led to pervious concrete being used in areas exposed to static or parked traffic and areas with slow moving traffic. At the two sites that included static and slow moving traffic, the permeability performance was better in the areas of static traffic than those with moving traffic. Each of the field sites had a unique mix design and some had multiple variations of one basic mix design. The relationship between the void content and hardened density of the pervious concrete cores was linear with none of the cores being visually identified as outliers. Substantial deterioration in pavement structure performance was identified at one site. Other field sites showed changes in structural capacity over the monitoring timeline. However, no locations of substantial decreases in structural capacity were identified. The surface condition of the sites over the analysis period indicated that compaction to the surface during construction was helpful in constructing a quality pavement. The results of the project indicated that pervious concrete will crack when joints are not included and may also crack similarly to conventional impermeable concrete pavements if joints are spaced too widely or do not match joints of adjacent pavement. Washing the pervious concrete pavement surface with a large hose or garden hose was found to be the most effective in improving permeability across a site and also in increasing the permeability of the pervious concrete. The initial permeability of the pervious concrete pavement was found to influence future performance. Freeze-thaw cycling and moisture were found to alter the internal structure of pervious concrete. However, did not generally lead to surface distress development. The application of sand as a winter maintenance method decreased the permeability, as did the use of a salt solution. However, neither winter maintenance method led to the permeability rates of laboratory slabs dropping below an acceptable level. All three slabs loaded with a salt solution deteriorated to a point where the slabs had failed. The initial permeability of the field sites proved to be important and although some sites started with what appeared to be very high permeability rates, these sites were successful in the multiple year evaluation in maintaining adequate permeability rates. The types of surface distresses that developed in the cores and slabs in the laboratory were generally not substantially worse at the field sites, suggesting that pedestrian and vehicle traffic do not necessarily escalate distresses caused by the Canadian climate and corresponding winter activities. The subsurface drainage that was quantified by the instrumentation included in three field sites confirmed observations from the surface of the pavement and exceeded other expectations. Two field sites exhibited limited drainage capabilities on the surface of the pervious concrete pavement, one shortly after construction, and the other within a year following construction. The subsurface analysis quantified and confirmed that moisture was not able to drain completely vertically through the pavement structures at these two sites due to the limited access in the pervious concrete pavement surface. In comparison, the subsurface drainage at another site surpassed the assumed behaviour of pervious concrete pavement structures. The pavement structure in general at this site was highly permeable and this was identified as moisture was not observed to be collecting in the bottom of the storage base layer at any time or for any period of time. The successful overall drainage performance of this site demonstrates the ability to effectively use pervious concrete pavement in Canada.

Pervious concrete pavement has the capacity to perform as two types of infrastructure: a pavement; and a stormwater management solution. It is a low impact development as it does not alter the natural hydrological cycle when implemented, unlike a conventional impermeable pavement. This research represents some of the initial investigations into pervious concrete pavement in Canada. The two research hypotheses of this research were the following: 1. Pervious concrete pavement can be successfully planned, designed, constructed and maintained in Canada for successful performance based on surface evaluations of permeability rate and surface condition. 2. Verification that the subsurface drainage capabilities of pervious concrete pavement are as described in literature and can be quantified using instrumentation. Through monitoring of the design, construction, performance and maintenance of five field sites across Canada and various laboratory pavement slabs, the behaviour of pervious concrete pavement in freeze-thaw conditions has been evaluated. This thesis presents the findings from the various phases of the life cycle of pervious concrete pavement: planning; design; construction; and maintenance. An interpretation of the performance of pervious concrete pavement both from the perspective of the surface and subsurface is included. The various field sites led to pervious concrete being used in areas exposed to static or parked traffic and areas with slow moving traffic. At the two sites that included static and slow moving traffic, the permeability performance was better in the areas of static traffic than those with moving traffic. Each of the field sites had a unique mix design and some had multiple variations of one basic mix design. The relationship between the void content and hardened density of the pervious concrete cores was linear with none of the cores being visually identified as outliers. Substantial deterioration in pavement structure performance was identified at one site. Other field sites showed changes in structural capacity over the monitoring timeline. However, no locations of substantial decreases in structural capacity were identified. The surface condition of the sites over the analysis period indicated that compaction to the surface during construction was helpful in constructing a quality pavement. The results of the project indicated that pervious concrete will crack when joints are not included and may also crack similarly to conventional impermeable concrete pavements if joints are spaced too widely or do not match joints of adjacent pavement. Washing the pervious concrete pavement surface with a large hose or garden hose was found to be the most effective in improving permeability across a site and also in increasing the permeability of the pervious concrete. The initial permeability of the pervious concrete pavement was found to influence future performance. Freeze-thaw cycling and moisture were found to alter the internal structure of pervious concrete. However, did not generally lead to surface distress development. The application of sand as a winter maintenance method decreased the permeability, as did the use of a salt solution. However, neither winter maintenance method led to the permeability rates of laboratory slabs dropping below an acceptable level. All three slabs loaded with a salt solution deteriorated to a point where the slabs had failed. The initial permeability of the field sites proved to be important and although some sites started with what appeared to be very high permeability rates, these sites were successful in the multiple year evaluation in maintaining adequate permeability rates. The types of surface distresses that developed in the cores and slabs in the laboratory were generally not substantially worse at the field sites, suggesting that pedestrian and vehicle traffic do not necessarily escalate distresses caused by the Canadian climate and corresponding winter activities. The subsurface drainage that was quantified by the instrumentation included in three field sites confirmed observations from the surface of the pavement and exceeded other expectations. Two field sites exhibited limited drainage capabilities on the surface of the pervious concrete pavement, one shortly after construction, and the other within a year following construction. The subsurface analysis quantified and confirmed that moisture was not able to drain completely vertically through the pavement structures at these two sites due to the limited access in the pervious concrete pavement surface. In comparison, the subsurface drainage at another site surpassed the assumed behaviour of pervious concrete pavement structures. The pavement structure in general at this site was highly permeable and this was identified as moisture was not observed to be collecting in the bottom of the storage base layer at any time or for any period of time. The successful overall drainage performance of this site demonstrates the ability to effectively use pervious concrete pavement in Canada.

Os diversos e indesejáveis problemas associados à ocorrência de inundações e de picos rápidos de cheia são comuns nos centros urbanos brasileiros, sendo agravados em decorrência da crescente impermeabilização das superfícies alavancada pelo crescimento das cidades. Uma das alternativas para reduzir esses problemas consiste no uso de pavimentações drenantes, que possibilitem a infiltração e colaborem com o retardo do escoamento das águas pluviais. Dentre as opções disponíveis, vem atraindo atenção, nos últimos anos, o denominado concreto permeável, material fabricado com uma composição granulométrica selecionada (sem agregado miúdo e com partículas de dimensões similares), de forma a gerar uma estrutura de grandes poros conectados, que permite uma rápida percolação de fluidos pelo seu interior, em grandes quantidades. Levando em consideração os diferentes desafios associados à drenagem urbana, as pesquisas no LEME voltaram-se para a investigação de uma nova possibilidade de utilização do concreto permeável, como material componente dos próprios elementos dos sistemas urbanos de drenagem pluvial. Sabe-se que um dos principais problemas de funcionamento desses sistemas consiste na obstaculização de suas entradas por materiais diversos em conjunto com a diminuição da área de passagem de água nas galerias pelo acúmulo de material nas mesmas, gerando entupimento parcial ou total. Nesses casos, o uso de concreto permeável pode viabilizar a passagem de elevados fluxos, ao mesmo tempo em que constitui uma barreira à passagem de detritos e um filtro natural das águas, potencialmente evitando o ingresso de materiais, lixo e partículas sólidas no interior das galerias do sistema de drenagem. Buscando contribuir para a avaliação da ideia, o presente trabalho foi concebido tendo como foco o estudo da utilização do concreto permeável para fabricação de elementos tipo placa, em substituição às grelhas utilizadas atualmente. Para orientar tecnicamente o estudo, tomou-se como referência o Caderno de Encargos do Departamento de Esgotos Pluviais (DEP) da cidade de Porto Alegre, que estabelece as características dessas grelhas. Após um estudo preliminar para ajuste do traço e caracterização básica do concreto permeável, foram moldados seis protótipos de placas com um traço 1:4 (cimento:areia), com dimensões similares às grelhas do DEP, confeccionadas em concreto permeável. As placas foram testadas quanto à capacidade de flexão e à permeabilidade (sendo esses últimos efetuados em corpos de prova extraídos das placas). Para fins de comparação, foi ensaiada, também, uma grelha real fabricada e disponibilizada pelo DEP. Adicionalmente, foram criados, no LEME, dispositivos especiais para simular os efeitos de chuva e de passagem de água, carreando material em suspensão, para avaliar o desempenho em termos de colmatação desses elementos. Os resultados dos ensaios de resistência mecânica e de permeabilidade indicaram que os novos elementos apresentam desempenho superior às grelhas convencionais, indicando que os estudos na direção da produção de elementos drenantes em concreto permeável são promissores e devem ser continuados. Os resultados do teste de colmatação indicam, no entanto, que procedimentos de manutenção e limpeza podem ser necessários se material pulverulento bloquear os poros do concreto permeável. / Many undesirable problems associated with the occurrence of floods and rapid flood peaks are common in Brazilian urban centers and are intensified due to the increase of waterproofing of surfaces caused by the growth of cities. An alternative to mitigate these problems is the use of draining pavements that allow infiltration and collaborate with the delay of storm water runoff. Among the available options, pervious concrete has been attracting attention in recent years. This is a special concrete made with selected particle size distribution (without coarse aggregate and particles of similar dimensions) to generate a structure containing large connected pores, which would 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 investigating a new possibility for the use of pervious concrete as a constituent material of urban 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 decrease 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 the passage of high flow rates, while constituting a barrier to the passage of debris and a natural water filter, preventing the entry of potentially granular material and solid waste particles 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 concrete for the manufacture of plate elements, which could be used to replace the grilles that are currently in use in sewers. In order to guide the study, the requirements of the Rain Sewage Department (Departamento de Esgotos Pluviais - DEP) from Porto Alegre were taken as a reference. After a preliminary study made to adjust and characterize the mix of pervious concrete to be used, six plates prototypes were fabricated using a 1:4 (cement:sand) proportion, with similar dimensions to the DEP grilles. These were then tested to check flexural capacity and 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 simulated, and the performance in terms of clogging of these elements was roughly assessed. For comparison, a conventional grille currently made by DEP was also tested. The results from the mechanical strength and permeability tests indicated that the pervious plates had superior performance when compared to the conventional grilles, indicating that studies toward the production of drainage elements in pervious concrete are promising and should be continued. 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.

Esta pesquisa teve por finalidade estudar concretos permeáveis para uso como camada de revestimento de pavimentos em áreas de veículos leves, por meio da realização de ensaios laboratoriais de caracterização mecânica e hidráulica para três diferentes misturas com variação do diâmetro máximo de agregados graúdos. Além disso, o estudo procurou interpretar o comportamento desse material quando solicitado por cargas de veículos, a partir de análises numéricas utilizando o software EverFE para análise de placas de concreto por elementos finitos. A caracterização mecânica foi realizada com base em ensaios de resistência à tração na flexão, tração indireta por compressão diametral, compressão, módulo de elasticidade estático e módulo de elasticidade dinâmico por equipamento ultrassônico. Para determinação da condutividade hidráulica foi utilizado um permeâmetro de carga constante. As análises mecanicistas envolveram estudos de placas de concreto permeável solicitadas por um eixo simples de rodas duplas com carga de 80 kN e por um eixo simples de roda simples com carga de 22 kN, simulando, nesse caso, um veículo utilitário leve. O material estudado apresentou para um índice de vazios de aproximadamente 0,25, valores de condutividade hidráulica na ordem de 0,14 cm/s, aproximadamente, caracterizando um material com boa drenabilidade. Com relação às características mecânicas, apresentou resistência à tração na flexão de aproximadamente 2,1 MPa e módulo de elasticidade estático na ordem de 15.000 MPa, se aproximando da metade dos valores normalmente observados em concretos convencionais de uso corrente na pavimentação. Por meio da realização das análises mecanicistas, foi possível avaliar que o material estudado apresenta resistência suficiente para ser utilizado como revestimento de pavimentos para áreas de veículos leves. / The main goal of this research was to study the pervious concrete material as the surface layer for light traffic pavement by carrying out a laboratorial analysis in order to better understand the mechanical and hydraulic behavior of three different coarse aggregate gradation mixtures. Besides that, it was applied a Finite Element Analysis in order to identify the pervious concrete behavior when loaded by different vehicle loads by using the EverFE Software The mechanical characterization was developed by evaluating the tests results of flexural strength, split tensile strength, compressive strength, Youngs Modulus and the non-destructive ultrasonic test. The hydraulic conductivity was measured using a constant head permeameter. In order to carry out the mechanistic analysis, it was considered a pervious concrete slab loaded by both an 80 kN dual wheel axle, and, to simulate a light vehicle, a 22 kN single wheel axle. The studied material has shown, considering the void ratio of 0,25, values of hydraulic conductivity around 0,14 cm/s, characterizing a material with good drenability characteristics. Besides that, it presented a flexural strength of 2,1 MPa and Youngs Modulus of 15.000 MPa, reaching the half of the values commonly used in regular concretes for pavements. By using the mechanistic analysis, it was possible to assess that this specific studied pervious concrete has enough strength to be used as the surface layer of pavements loaded by lightweight vehicles.

Os diversos e indesejáveis problemas associados à ocorrência de inundações e de picos rápidos de cheia são comuns nos centros urbanos brasileiros, sendo agravados em decorrência da crescente impermeabilização das superfícies alavancada pelo crescimento das cidades. Uma das alternativas para reduzir esses problemas consiste no uso de pavimentações drenantes, que possibilitem a infiltração e colaborem com o retardo do escoamento das águas pluviais. Dentre as opções disponíveis, vem atraindo atenção, nos últimos anos, o denominado concreto permeável, material fabricado com uma composição granulométrica selecionada (sem agregado miúdo e com partículas de dimensões similares), de forma a gerar uma estrutura de grandes poros conectados, que permite uma rápida percolação de fluidos pelo seu interior, em grandes quantidades. Levando em consideração os diferentes desafios associados à drenagem urbana, as pesquisas no LEME voltaram-se para a investigação de uma nova possibilidade de utilização do concreto permeável, como material componente dos próprios elementos dos sistemas urbanos de drenagem pluvial. Sabe-se que um dos principais problemas de funcionamento desses sistemas consiste na obstaculização de suas entradas por materiais diversos em conjunto com a diminuição da área de passagem de água nas galerias pelo acúmulo de material nas mesmas, gerando entupimento parcial ou total. Nesses casos, o uso de concreto permeável pode viabilizar a passagem de elevados fluxos, ao mesmo tempo em que constitui uma barreira à passagem de detritos e um filtro natural das águas, potencialmente evitando o ingresso de materiais, lixo e partículas sólidas no interior das galerias do sistema de drenagem. Buscando contribuir para a avaliação da ideia, o presente trabalho foi concebido tendo como foco o estudo da utilização do concreto permeável para fabricação de elementos tipo placa, em substituição às grelhas utilizadas atualmente. Para orientar tecnicamente o estudo, tomou-se como referência o Caderno de Encargos do Departamento de Esgotos Pluviais (DEP) da cidade de Porto Alegre, que estabelece as características dessas grelhas. Após um estudo preliminar para ajuste do traço e caracterização básica do concreto permeável, foram moldados seis protótipos de placas com um traço 1:4 (cimento:areia), com dimensões similares às grelhas do DEP, confeccionadas em concreto permeável. As placas foram testadas quanto à capacidade de flexão e à permeabilidade (sendo esses últimos efetuados em corpos de prova extraídos das placas). Para fins de comparação, foi ensaiada, também, uma grelha real fabricada e disponibilizada pelo DEP. Adicionalmente, foram criados, no LEME, dispositivos especiais para simular os efeitos de chuva e de passagem de água, carreando material em suspensão, para avaliar o desempenho em termos de colmatação desses elementos. Os resultados dos ensaios de resistência mecânica e de permeabilidade indicaram que os novos elementos apresentam desempenho superior às grelhas convencionais, indicando que os estudos na direção da produção de elementos drenantes em concreto permeável são promissores e devem ser continuados. Os resultados do teste de colmatação indicam, no entanto, que procedimentos de manutenção e limpeza podem ser necessários se material pulverulento bloquear os poros do concreto permeável. / Many undesirable problems associated with the occurrence of floods and rapid flood peaks are common in Brazilian urban centers and are intensified due to the increase of waterproofing of surfaces caused by the growth of cities. An alternative to mitigate these problems is the use of draining pavements that allow infiltration and collaborate with the delay of storm water runoff. Among the available options, pervious concrete has been attracting attention in recent years. This is a special concrete made with selected particle size distribution (without coarse aggregate and particles of similar dimensions) to generate a structure containing large connected pores, which would 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 investigating a new possibility for the use of pervious concrete as a constituent material of urban 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 decrease 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 the passage of high flow rates, while constituting a barrier to the passage of debris and a natural water filter, preventing the entry of potentially granular material and solid waste particles 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 concrete for the manufacture of plate elements, which could be used to replace the grilles that are currently in use in sewers. In order to guide the study, the requirements of the Rain Sewage Department (Departamento de Esgotos Pluviais - DEP) from Porto Alegre were taken as a reference. After a preliminary study made to adjust and characterize the mix of pervious concrete to be used, six plates prototypes were fabricated using a 1:4 (cement:sand) proportion, with similar dimensions to the DEP grilles. These were then tested to check flexural capacity and 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 simulated, and the performance in terms of clogging of these elements was roughly assessed. For comparison, a conventional grille currently made by DEP was also tested. The results from the mechanical strength and permeability tests indicated that the pervious plates had superior performance when compared to the conventional grilles, indicating that studies toward the production of drainage elements in pervious concrete are promising and should be continued. 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.

Os diversos e indesejáveis problemas associados à ocorrência de inundações e de picos rápidos de cheia são comuns nos centros urbanos brasileiros, sendo agravados em decorrência da crescente impermeabilização das superfícies alavancada pelo crescimento das cidades. Uma das alternativas para reduzir esses problemas consiste no uso de pavimentações drenantes, que possibilitem a infiltração e colaborem com o retardo do escoamento das águas pluviais. Dentre as opções disponíveis, vem atraindo atenção, nos últimos anos, o denominado concreto permeável, material fabricado com uma composição granulométrica selecionada (sem agregado miúdo e com partículas de dimensões similares), de forma a gerar uma estrutura de grandes poros conectados, que permite uma rápida percolação de fluidos pelo seu interior, em grandes quantidades. Levando em consideração os diferentes desafios associados à drenagem urbana, as pesquisas no LEME voltaram-se para a investigação de uma nova possibilidade de utilização do concreto permeável, como material componente dos próprios elementos dos sistemas urbanos de drenagem pluvial. Sabe-se que um dos principais problemas de funcionamento desses sistemas consiste na obstaculização de suas entradas por materiais diversos em conjunto com a diminuição da área de passagem de água nas galerias pelo acúmulo de material nas mesmas, gerando entupimento parcial ou total. Nesses casos, o uso de concreto permeável pode viabilizar a passagem de elevados fluxos, ao mesmo tempo em que constitui uma barreira à passagem de detritos e um filtro natural das águas, potencialmente evitando o ingresso de materiais, lixo e partículas sólidas no interior das galerias do sistema de drenagem. Buscando contribuir para a avaliação da ideia, o presente trabalho foi concebido tendo como foco o estudo da utilização do concreto permeável para fabricação de elementos tipo placa, em substituição às grelhas utilizadas atualmente. Para orientar tecnicamente o estudo, tomou-se como referência o Caderno de Encargos do Departamento de Esgotos Pluviais (DEP) da cidade de Porto Alegre, que estabelece as características dessas grelhas. Após um estudo preliminar para ajuste do traço e caracterização básica do concreto permeável, foram moldados seis protótipos de placas com um traço 1:4 (cimento:areia), com dimensões similares às grelhas do DEP, confeccionadas em concreto permeável. As placas foram testadas quanto à capacidade de flexão e à permeabilidade (sendo esses últimos efetuados em corpos de prova extraídos das placas). Para fins de comparação, foi ensaiada, também, uma grelha real fabricada e disponibilizada pelo DEP. Adicionalmente, foram criados, no LEME, dispositivos especiais para simular os efeitos de chuva e de passagem de água, carreando material em suspensão, para avaliar o desempenho em termos de colmatação desses elementos. Os resultados dos ensaios de resistência mecânica e de permeabilidade indicaram que os novos elementos apresentam desempenho superior às grelhas convencionais, indicando que os estudos na direção da produção de elementos drenantes em concreto permeável são promissores e devem ser continuados. Os resultados do teste de colmatação indicam, no entanto, que procedimentos de manutenção e limpeza podem ser necessários se material pulverulento bloquear os poros do concreto permeável. / Many undesirable problems associated with the occurrence of floods and rapid flood peaks are common in Brazilian urban centers and are intensified due to the increase of waterproofing of surfaces caused by the growth of cities. An alternative to mitigate these problems is the use of draining pavements that allow infiltration and collaborate with the delay of storm water runoff. Among the available options, pervious concrete has been attracting attention in recent years. This is a special concrete made with selected particle size distribution (without coarse aggregate and particles of similar dimensions) to generate a structure containing large connected pores, which would 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 investigating a new possibility for the use of pervious concrete as a constituent material of urban 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 decrease 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 the passage of high flow rates, while constituting a barrier to the passage of debris and a natural water filter, preventing the entry of potentially granular material and solid waste particles 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 concrete for the manufacture of plate elements, which could be used to replace the grilles that are currently in use in sewers. In order to guide the study, the requirements of the Rain Sewage Department (Departamento de Esgotos Pluviais - DEP) from Porto Alegre were taken as a reference. After a preliminary study made to adjust and characterize the mix of pervious concrete to be used, six plates prototypes were fabricated using a 1:4 (cement:sand) proportion, with similar dimensions to the DEP grilles. These were then tested to check flexural capacity and 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 simulated, and the performance in terms of clogging of these elements was roughly assessed. For comparison, a conventional grille currently made by DEP was also tested. The results from the mechanical strength and permeability tests indicated that the pervious plates had superior performance when compared to the conventional grilles, indicating that studies toward the production of drainage elements in pervious concrete are promising and should be continued. 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.

La presente tesis consiste en presentar una propuesta sostenible que ayude en el control y almacenamiento del agua de lluvia para evitar inundaciones y daños producidos en los estacionamientos de los hospitales en la ciudad de Arequipa. Se evaluaron dieciocho diseños de mezclas, nueve realizados con agregado grueso Huso 7 y los otros nueve con Huso 67. Para los diferentes diseños se cambió el porcentaje de agregado fino, la relación agua/cemento y la dosis de los aditivos. Por cada diseño de mezcla se elaboraron nueve probetas destinadas al ensayo de resistencia a la compresión, tres por cada edad, ensayadas a los 7, 14 y 28 días; se utilizaron 2 vigas de 6”x6”x20” para determinar el Módulo de Rotura y 2 probetas de 4”x8” para hallar la tasa de permeabilidad, para lo cual se necesitó realizar una réplica del permeabilímetro expuesto en el ACI 522. Los resultados de todos los ensayos serán presentados y comparados entre sí para determinar el grado de influencia de los mismos. Además, también se realizará un análisis costo beneficio por metro cuadrado para determinar qué tanto varía el costo del concreto permeable en comparación con el concreto convencional. Finalmente, se realizará un análisis cuantitativo entre los dieciocho diseños de mezcla y el concreto convencional. Para así determinar cuál es la mezcla óptima que cumpla con los requisitos necesarios para ser implementado en los estacionamientos de los hospitales en Arequipa y pueda competir en el mercado con el concreto convencional. / The present thesis consists of presenting a sustainable proposal that helps in the control and storage of rainwater to avoid floods and damages produced in the parking lots of hospitals in the city of Arequipa. Eighteen mix designs were evaluated, nine made with coarse aggregate Spindle 7 and the other nine with Spindle 67. For the different designs, the percentage of fine aggregate, the water / cement ratio and the dose of the additives were changed. For each mix design, nine specimens were prepared for the compression resistance test, three for each age, tested at 7, 14 and 28 days; 2 beams of 6 ”x6” x20 ”were used to determine the Modulus of Break and 2 specimens of 4” x8 ”to find the permeability rate, for which it was necessary to make a replica of the permeabilimeter exposed in the ACI 522. The results of all the tests will be presented and compared with each other to determine the degree of influence between them. In addition, a cost benefit analysis per square meter will also be performed to determine how much the cost of pervious concrete varies compared to conventional concrete. Finally, a quantitative analysis will be performed between the eighteen mix designs and conventional concrete. In order to determine which is the optimal mix that meets the necessary requirements to be implemented in hospital´s parking lots in Arequipa and can compete in the market with conventional concrete. / Tesis

The pervious concrete system and its corresponding strength are as important as its permeability characteristics. The strength of the system not only relies on the compressive strength of the pervious concrete but also on the strength of the soil beneath it for support. Previous studies indicate that pervious concrete has lower compressive strength capabilities than conventional concrete and will only support light traffic loadings. This thesis investigated prior studies on the compressive strength on pervious concrete as it relates to water-cement ratio, aggregate-cement ratio, aggregate size, and compaction and compare those results with results obtained in laboratory experiments conducted on samples of pervious concrete cylinders created for this purpose. The loadings and types of vehicles these systems can withstand will also be examined as well as the design of appropriate thickness levels for the pavement. Since voids are supposed to reduce the strength of concrete 1% for every 5% voids(Klieger, 2003), the goal is to find a balance between water, aggregate, and cement in order to increase strength and permeability, two characteristics which tend to counteract one another. In this study, also determined are appropriate traffic loads and volumes so that the pervious concrete is able to maintain its structural integrity. The end result of this research will be a recommendation as to the water-cement ratio, the aggregate-cement ratio, aggregate size, and compaction necessary to maximize compressive strength without having detrimental effects on the permeability of the pervious concrete system. This research confirms that pervious concrete does in fact provide a lower compressive strength than that of conventional concrete; compressive strengths in acceptable mixtures only reached 1700 psi. Extremely high permeability rates were achieved in most all mixtures regardless of the compressive strength. Analysis of traffic loadings reinforce the fact that pervious concrete cannot be subjected to large numbers of heavy vehicle loadings over time although pervious concrete would be able to sustain low volumes of heavy loads if designed properly. Calculations of pavement thickness levels indicate these levels are dependent on the compressive strength of the concrete, the quality of the subgrade beneath the pavement, as well as vehicle volumes and loadings.