Use of scrap tire rubber in place of SBS in modified asphalt as an environmentally correct alternative for Brazil

Reusing scrap tires has become a worldwide challenge, especially due to the great difficulty in finding ecologically and economically feasible ways to dispose of them. This has led to the creation of specific programs and legislation for reusing scrap tires. Research has shown that a certain percentage of scrap tire rubber can be added to asphalt compositions, and this has become a worldwide practice. This paper describes the properties of four asphalt compositions modified with scrap tire rubber (STR) prepared in the laboratory. These properties are then compared with those of asphalt modified with styrene butadiene styrene (SBS), a synthetic polymer and one of the most common modifiers, to verify the feasibility of using scrap tire rubber as a substitute for SBS. The scope of this study does not include an analysis of how STR affects end-of-life asphalt. The main findings indicate that STR is a potential substitute of SBS in paving material, and although it does not meet some of the standard specifications when compared with SBS, these issues can be overcome by proper care during storage and transportation. The substitution of SBS by STR also showed the potential for about 10% in expenditure savings. (C) 2012 Elsevier Ltd. All rights reserved.

The use of shallow seismic reflection technique in near surface exploration of urban sites: An evaluation in the city of SãO Paulo, Brazil

In order to evaluate the use of shallow seismic technique to delineate geological and geotechnical features up to 40 meters depth in noisy urban areas covered with asphalt pavement, five survey lines were conducted in the metropolitan area of São Paulo City. The data were acquired using a 24-bit, 24-channel seismograph, 30 and 100 Hz geophones and a sledgehammer-plate system as seismic source. Seismic reflection data were recorded using a CMP (common mid point) acquisition method. The processing routine consisted of: prestack band-pass filtering (90-250 Hz); automatic gain control (AGC); muting (digital zeroin) of dead/noisy traces, ground roll, air-wave and refracted-wave; CMP sorting; velocity analyses; normal move-out corrections; residual static corrections; f-k filtering; CMP stacking. The near surface is geologically characterized by unconsolidated fill materials and Quaternary sediments with organic material overlying Tertiary sediments with the water table 2 to 5 m below the surface. The basement is composed of granite and gneiss. Reflections were observed from 40 milliseconds to 65 ms two-way traveltime and were related to the silt clay layer and fine sand layer contact of the Tertiary sediments and to the weathered basement. The CMP seismic-reflection technique has been shown to be useful for mapping the sedimentary layers and the bedrock of the São Paulo sedimentary basin for the purposes of shallow investigations related to engineering problems. In spite of the strong cultural noise observed in these urban areas and problems with planting geophones we verified that, with the proper equipment, field parameters and particularly great care in data collection and processing, we can overcome the adverse field conditions and to image reflections from layers as shallow as 20 meters.

Indicadores de floresta urbana a partir de imagens aéreas multiespectrais de alta resolução

The present work evaluated urban forest indicators, acquired through airborne high-resolution multiespectral images, on the quality of the urban design and its vegetative fraction, in special its trees, in nine neighborhoods of Piracicaba, SP. There were made supervised classifications for characterization of intra-urban elements and the proportions obtained, as exposed soil, tree cover, lawns, asphalt, concrete pavements and roofs. They were studied for the measurement of the urban forest in each place. These variables were related to each other, as well as with the independent variables: population density, people with more than fifteen years of study and family heads with income above twenty minimum wages, obtained through population census. Through the analysis of linear regression variables were identified for intra-urban areas evaluation. Correlations were made and linear regressions among the data obtained from the image and among the proposed indicators. Negative correlations were obtained among population density and arboreal covering and the evaluated indices, in accordance with the predicted in the literature. Composite indicators are proposed, as: the proportion between arboreous space on waterproof space (PAW) and the proportion between arboreous space on building space (PAB). It is concluded by the possibility of the use of those indicators for evaluation of the urban forest and definition of priorities in the execution of ordinances to the improvement of the urban forestry, being prioritized the application of resources in the most lacking neighborhoods.

Ensaios comparativos de mistura asfáltica pré-misturado a frio com adição de borracha de pneu

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Concreto de alto desempenho com adição de resíduos de borracha de pneu

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Reaproveitamento de pneus inservíveis: determinação em laboratório das características do asfalto modificado SBS comparadas às do asfalto com pó de borracha

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação do ruído e da vibração no posto de trabalho em dois tratores agrícolas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desenvolvimento e avaliação do desempenho de um equipamento para ensaio dinâmico de rodado agrícola individual

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Tubos de concreto com adição de resíduos de borracha de pneu

Pós-graduação em Engenharia Civil - FEIS

Projeto de um transdutor binocular utilizando extensometria e aplicação na pesagem rodoviária

With the passage of time, the variety of companies from each branch has gradually grown throughout the country. As a consequence, the logistics to attend to such demand has grown in the same proportion. One factor to highlight about this rapid growth is the increase of freight vehicles roaming the roads, often carrying loads over the limit established by law. At first it may seem that this would not bring any problem, however, note that an excessive number of overloads ends up deteriorating the asphalt, causing ondulations, potholes and other imperfections on the roads, which can cause accidents. In addition, the money spent for the maintenance of the roads is high. Thinking about it, it was established by law a regulation that restricts the weight limit for these vehicles, through axle weighing, subject to a fine. With this control the road floor is preserved for longer, requiring less maintenance expenses. The weighing stations use load cells to display the inferred weight, these cells use strain gages in its construction. The following work presents a methodology to dimension a binocular load cell, its main elements and its dimensioning. Showing how different materials can affect the dimensioning, so that can work satisfactorily. It also presents an overview of how are the parameters for weighing, and fines

Aplicação de sistema de gestão da qualidade na execução de obras de pavimentação asfáltica, baseado nas diretrizes da ABNT NBR ISO 9001:2008

This work brings to its content proposed deployment of a system of quality management in paving asphalt based on the elaboration of a basic training to meet those entering this area of civil engineering at a technical manual for the implementation of major services running on paving of roads. The training was designed to serve both those entering the field of asphalt paving, synthesizing the complex processes involved in paving services and providing an overview of the steps in implementation thereof, as well as entrants must meet the enterprise user of this system, providing them an idea of the method used by the company designing the paving of roads. The technical manual presented in turn, has 8 (eight) of the main services components of a work of paving, which are: Mobilization and Maintenance of construction site, Regularization and subfloor preparation, execution or sub-base BGS base (graded gravel plain), Execution of sub-base or base BGTC (graded gravel treated with cement), Implementation of subbase or base Macadam hydraulic Priming bituminous waterproofing, asphalt binder Priming and finally the execution flexible pavement - HMA (hot milled asphalt concrete). These services are presented in the form of IT-Education work, this seven items are presented that guide the performance of services, thus providing overall guidelines to perform the services described in it. The development of IT's was based on experiences in day-to-day paving near the theoretical precepts presented in the literature, so the conditions specified in these documents aim to always guide the implementation of services in general, giving the process a versatility major operation, as this work takes into account the dynamics of such services, as well as the variety of their execution according to local conditions and specified in the project. So in general we can say that this ... (Complete abstract click electronic access below)

Land use and thermal comfort in the county of Ourinhos, SP

This study aims to analyze the thermal comfort in urban areas for different land uses. The ENVImet microclimatic model has been used for urban boundary layer simulation, providing the following thermal comfort indexes: PMV (Predicted Mean Vote) and PPD (Predicted Percentage of Dissatisfaction). The chosen area covers the central area in the city of Ourinhos, located in southeastern Brazilian city, with subtropical climate. Four simulations were accomplished: an area with real buildings and vegetation on site, a “grassy” area where buildings have been replaced by grass in the central area, another grassy area, known as “grass/tree”, with additional trees in, and a final area called “Park” also grassy, where trees were added all over the area. The structures which showed thermal comfort within the ISO 7730 standards were the grassy area with no trees at 9 a.m., and a paved area, as well as the park area at 3 p.m. Other situations have presented values of PMV and PPD off the limits required by the rules; they were very close to those values. The only point that presented a far cry from the comfort required was the spot in the asphalt at 9 a.m. The other situations showed PMV and PPD values not far from the limits of comfort. Only the point on the asphalt showed values far from the limit of comfort at 9 a.m.