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This study evaluated the technical potential of a stabilizer derived from the intimate mixture of steel waste (powder electric arc furnace oxidizing slag - PES) and fly ash to improve soil engineering properties for application in urban paving. This evaluation was performed by laboratory tests to characterize, through CBR tests and unconfined compression tests, the mechanical behavior of compacted residual soil samples of the Alto Paraopeba region, state of Minas Gerais, Brazil, and mixtures of these soils with the stabilizer. For the peculiarities of the research, it was possible to demonstrate the technical viability of the use of steel waste in urban paving works, highlighting the relevance of the proposal in meeting the needs of steel companies to confer a sustainable disposal of waste materials, and the need of municipalities surrounding such companies to providing for, with low-cost materials, significant demands of unpaved road networks.

The behavior of piled foundations is influenced by several factors, especially those related to the geometry of the foundations, the number of piles, the height of the element that tops the piles and the type of soil in which the foundations are inserted. Given the various situations and variations of parameters to be analyzed, it is common to use numerical modeling for the analysis of geotechnical engineering problems. The piled rafts in this article are numerically analyzed by means of the three-dimensional finite element method using CESAR-LCPC ® v.5 software. Thus, it was possible to conduct various analyses of piled rafts by varying the amount of piles and the thickness of the raft supported on the soil and piles. The results demonstrate that piled raft foundations tend to make displacements uniform, thus minimizing problems with differential settlement in structures. The thickness of the plate of the piled raft influences the load distribution in the piles under the raft when the piles are supported on the ground. The relative stiffness (K rs ), which is the ‘stiffness’ of the piled raft combined with the soil, increases with increases in the amount of piles and the thickness of the piled raft.

The selective collection of domestic solid waste occurs in a fragmented and disorganized way in most parts of Brazil, through the anonymous and precarious work of informal garbage collectors. The Brazilian law 12.305/2010 (BRASIL, 2010) meets the social need for a regulatory milestone of this waste management and makes it clear the intention to include recylable material collectors. This paper aimed to evaluate the implementation of a program of selective collection of domestic solid waste with the segregation at origin and the participation of recyclable material collectors in the assistance established by PNRS (National Policy for Solid Waste). The research strategy used was a case study of the program of selective waste collection in the city of Londrina, Paraná State, Brazil. The project included document analysis, visits to the sorting units and collection areas in order to monitor the data collection process. The adverse aspects of the program were concentrated on technological and health dimensions, and the positive aspects were concentrated on environmental, social, cultural, economic and political dimensions. This article provides important data and indicators to the authorities responsible for managing solid waste, leading to reflection on the actions to be implemented, and also instruction on investments and planning actions.

O programa experimental de pesquisa apresentado se desenvolveu na região do Alto Paraopeba, no Estado de Minas Gerais, na região Sudeste do Brasil. O objetivo principal foi promover a avaliação geotécnica de perfis de solos residuais de cortes de rodovias e estradas vicinais, quanto à potencialidade da interferência antrópica sobre a suscetibilidade desses solos aos processos erosivos acelerados. A metodologia aplicada neste estudo consistiu na realização de ensaios de caracterização geotécnica, de infiltrabilidade e de perda de massa por imersão modificada de amostras de solos desses perfis, utilizando os parâmetros físicos e de avaliação indireta de erodibilidade apresentados na proposta de 2000 de Bastos e outros autores. Os resultados para avaliação indireta de erodibilidade, oriundos de ensaios baseados na metodologia MCT, destacaram as diferentes suscetibilidades dos solos investigados à erosão hídrica. Considerando-se os resultados obtidos no presente trabalho, os parâmetros utilizados pelos referidos autores apresentaram-se como complementares aos critérios convencionais, permitindo um adequado enquadramento dos solos tropicais estudados às suas respectivas classes de erodibilidade. Dentre as amostras estudadas, detectou-se maior erodibilidade nas amostras YRS e PRS, respectivamente nas condições natural e pré-umedecida, bem como não se observou erodibilidade nas amostras RRS e WRS. The experimental research program was developed in the Alto Paraopeba region, state of Minas Gerais, Southeastern Brazil. The main objective was to promote the geotechnical evaluation of soil samples from four cut slopes in residual soil profiles of highways and local secondary roads in order to assess the potential of the anthropic impact on the soil susceptibility to accelerated erosion processes. Soil samples were named: red residual soil (RRS); pink residual soil (PRS); yellow residual soil (YRS); and white residual soil (WRS). The methodology used consisted of geotechnical characterization tests, infiltration rate and modified mass loss by immersion tests performed on soil samples from these profiles, using the physical parameters and indirect assessment of erodibility proposed in 2000 by Bastos et al. The results of indirect assessment of erodibility, which were derived from tests based on the MCT methodology, highlighted the different susceptibility of the investigated soils to hydric erosion. The parameters proposed by the referred authors were complementary to conventional criteria for an adequate classification of tropical soils into their respective classes of erodibility. Among the tested soil samples, the highest erodibility was associated with the YRS and PRS, respectively, in the natural and pre-moistened conditions, as well as it was not detected erodibility in the RRS and WRS.