ABSTRACT Waste generation is increasing due to population growth, urbanization, and economic development, especially in developing countries. Knowledge obtained on the generation of construction and demolition waste through forecasts can help decision makers adopt more efficient management practices, being fundamental to prevent the development of environmental issues. The objective of this article was to develop a model for forecasting the generation of construction and demolition waste for medium-sized Brazilian cities, using data from the municipality of Varginha, Minas Gerais. A multiple linear model (R2 = 0.880) was developed using Urban expansion, Gross Domestic Product (GDP), and GDP per capita as independent variables to predict the amount of construction and demolition waste generated in 2020 and the amount that will be produced in 2040 in the municipality. The results of applying the model indicated an increase of 18.27% in the amount of construction and demolition waste generated in the municipality, when comparing the 2020 (39,940 t) and 2040 (47,238 t) scenarios. The efficiency of the model was also verified when applying it in six other Brazilian cities of similar population size and that had research carried out on the generation of construction and demolition waste . The difference between the amount of construction and demolition waste obtained by the authors and those calculated by the model was less than 13%. The results of this research can contribute to the development of efficient construction and demolition waste management strategies, considering that it provides a tool for the resolution of current environmental problems and also allows the adoption of proactive actions for the correct management in future scenarios. growth urbanization countries practices issues mediumsized medium sized Varginha Gerais R2 R (R 0.880 0880 0 880 expansion GDP, , (GDP) 202 204 1827 18 27 18.27 39,940 39940 39 940 (39,94 t 47,238 47238 47 238 (47,23 scenarios 13 13% strategies 0.88 088 88 (GDP 20 182 1 2 18.2 39,94 3994 3 94 (39,9 47,23 4723 4 23 (47,2 0.8 08 8 18. 39,9 399 9 (39, 47,2 472 (47, 0. 39, (39 47, (47 (3 (4 (

RESUMO A geração de resíduos está aumentando em função do crescimento da população, urbanização e desenvolvimento econômico, especialmente nos países em desenvolvimento. O conhecimento do quantitativo de resíduo de construção e demolição gerado por meio de previsões pode auxiliar os tomadores de decisões a adotarem práticas mais eficientes de gestão, sendo fundamentais para prevenir o desenvolvimento dos problemas ambientais. O objetivo deste artigo foi desenvolver um modelo de previsão de geração dos resíduos de construção e demolição para cidades brasileiras de médio porte populacional, utilizando como estudo de caso o munícipio de Varginha (MG). Foi elaborado um modelo linear múltiplo (R2 = 0,880), empregando como variáveis independentes a expansão urbana, o Produto Interno Bruto (PIB) e o PIB per capita para prever o quantitativo de resíduo de construção e demolição gerado em 2020 e a quantidade de resíduo que será produzida em 2040 no município. Os resultados da aplicação do modelo indicaram aumento de 18,27% no quantitativo de resíduo de construção e demolição gerado no município, quando comparados o cenário de 2020 (39.940 t) e de 2040 (47.238 t). Também foi verificada a eficiência do modelo ao aplicá-lo em outras seis cidades brasileiras de similar porte populacional e que possuíam pesquisas sobre a geração de resíduo de construção e demolição. A diferença do quantitativo de resíduo de construção e demolição obtido pelos autores e os calculados pelo modelo foram inferiores a 13%. Os resultados desta pesquisa podem contribuir para o desenvolvimento de estratégias de gestão de resíduos de construção e demolição eficientes, já que fornece uma ferramenta para resolução dos problemas ambientais atuais e também permite a adoção de ações proativas para a correta gestão em cenários futuros. população econômico MG. MG . (MG) R2 R (R 0,880, 0880 0,880 , 0 880 0,880) urbana (PIB 202 204 município 1827 18 27 18,27 39.940 39940 39 940 (39.94 t 47.238 47238 47 238 (47.23 t. aplicálo aplicá lo 13 13% futuros (MG 088 0,88 88 20 182 1 2 18,2 39.94 3994 3 94 (39.9 47.23 4723 4 23 (47.2 08 0,8 8 18, 39.9 399 9 (39. 47.2 472 (47. 0, 39. (39 47. (47 (3 (4 (

Abstract The use of slate waste can help to reduce the impacts caused to the environment due to the decrease of the appropriate disposal areas and the disordered consumption of raw material. This article presents an analysis of the Resilient Modulus (RM) and the California Bearing Ratio (CBR) of this waste in mixtures with clayey soil. To analyze variations in RM and CBR due to the increase in the slate waste content, tests were carried out on reference mixtures (REF) and mixtures containing slate waste (SLT). The tests were carried out for mixtures of granular material (gneiss for REF and slate waste for SLT) and clay soil, containing different levels of granular materials (50%, 60%, 70%, 80% and 90%) It was observed that the values of Resilient Modulus and California Bearing Ratio of the SLT mixtures increased 62.8% and 127.0% with the addition of the slate waste between the SLT 50/50 and SLT 90/10 mixtures, respectively. This behavior was similar to that presented by the REF mixtures, which increased 125.0% in RM and 60.1% in CBR for the same addition of granular material. The results obtained indicate that the mixtures containing slate waste presented RM and CBR similar to those of conventional materials (such as the REF mixtures) used in layers of sub-base and the base of pavements. Finally, it was concluded that the relationship between RM and CBR is non-linear for both mixtures (REF and SLT) in function of granular material addition.

Resumo A heterogeneidade dos resíduos de construção e demolição dificulta seu uso sistemático, consequentemente, têm-se problemas com a disposição final e a contínua extração e uso de recursos não renováveis para fabricação de concretos. Essa heterogeneidade decorre, majoritariamente, da não segregação dos diversos constituintes dos resíduos durante seu processamento. O presente artigo analisa a necessidade da segregação dos resíduos de construção e demolição em diferentes tipos - cerâmicas de argila e cimentícios - e as consequências da utilização desses materiais como substituintes dos agregados naturais graúdos em concretos estruturais. Para tanto, foram fabricados concretos com 0, 25, 50 e 100% de agregados reciclados, sendo três tipos de resíduos utilizados: cimentícios, cerâmicos e uma mistura dos dois, nas proporções obtidas na usina de reciclagem. As conclusões apontam não ser necessária a segregação do resíduo utilizado, uma vez que os resultados apresentam desempenho similar dos concretos com agregados cimentícios e com agregados mistos. As performances reológica e mecânica são parâmetros afetados negativamente pela adição de resíduos. Já o desempenho com relação à durabilidade pode ser melhorado com o uso de agregados reciclados.

Abstract The great heterogeneity of construction and demolition waste (CDW) hinders its systematic use, leading to problems in its final disposal and in the continual extraction and use of non-renewable resources in concrete manufacturing. This heterogeneity derives primarily from the fact that manufacturers do not segregate the wide variety of CDW components during their processing. This paper analyses the need to segregate CDW into two different types - clay ceramics (red) and rocks and cement (gray) - and the consequences of using these materials as substitutes for natural coarse aggregates in structural concrete. Hence, different concretes were manufactured with 25, 50 and 100% CDW, using three types of waste: cementitious, ceramic and a mixture of both. The conclusion is that it is not necessary to segregate the waste from the recycling plant, since the results show that the concrete with cementitious aggregates and the one with mixed aggregates perform similarly. In addition, the use of CDW affects the characteristics of the concrete. Rheological and mechanical performance are parameters negatively affected by the use of waste. However, durability may improve with the use of recycled aggregates.

ABSTRACT Sugar cane bagasse is a residue of the sugar-alcohol industry, and its main destination is represented by burning boilers for power generation. The bagasse cogeneration of power produces a sugar cane bagasse ash (SCBA) residue that does not have a useful destination. Ashes are commonly studied as pozzolan in Portland cement production. International Standards indicate the use of pozzolan with up to 50% substitution. In the present work, we investigate the use of SCBA as an addition in Portland cement. For this purpose, Portland cement was prepared by substituting cement with 0, 10, 20, and 30% processed SCBA in volume. The ashes were processed by re-burning and grinding and were then characterized by scanning electron microscopy, X-ray diffraction, laser granulometry, X-ray fluorescence spectrometry, the Chapelle method, and pozollanic activity. To evaluate the cement with substitution, we used the mortar recommended by NBR 7215. The mechanical properties of the cements with replacement were analysed through tests of the compressive strength and flexural strength of mortars. The results appear interesting and support the possible use of SCBA in the production of cement from the aspect of mechanical properties evaluated.

Abstract The steel-concrete bond is a fundamental property in reinforced concrete structures. Although there are several studies on the steel-concrete bond, few of them have evaluated the performance of reinforcing bars with diameters less than 10.0 mm, which includes 5.0, 6.3, and 8.0 mm diameters, which are normally used in reinforced-concrete elements. This study experimentally evaluates the bond between thin steel bars and concrete of 25MPa compression strength. Three types of methods of testing the bond-strength were performed: confined bar test, pull-out test and beam test. It was compared the adequacy of the tests to calculate the conformation coefficient of the bars. The results of the confined bars tests show that this test may be inadequate to determine the surface conformation coefficient of reinforcing bars thinner than 10 mm, especially for notched (CA-60) steel bars. The pull-out test resulted in better results in terms of evaluating the bond behavior. Regarding the specimens for the pull-out tests, a modified model with an anchorage length equal to 10 times the bar diameter is suggested. Therefore, the main contribution of this study, based on the results obtained and the methodology used, is to present a proposal for the evaluation of steel-concrete bond for thin rebars.

Objetivou-se determinar aspectos bioquímicos, morfométricos e biomecânicos dos fêmures de frangos de corte. Utilizaram-se 600 pintos de 1 dia de idade, machos e fêmeas, de três híbridos (Hb1 e Hb2 - UFV e Hb3 - comercial). As aves foram alimentadas à vontade com rações para as fases inicial (1 a 21 dias), de crescimento (22 a 35 dias) e final (36 a 42 dias). O delineamento experimental foi inteiramente casualizado em esquema fatorial 3 × 2, composto de três cruzamentos e dois sexos, cinco repetições e dez aves por unidade experimental (boxe). Avaliaram-se no fêmur o peso, o comprimento, a área da seção transversal, o momento de inércia, a carga máxima na flexão, a tenacidade e resistência à flexão, o conteúdo de proteínas colagenosas e não-colagenosas e o peso vivo das aves. Aos 21, 28, 35 e 42 dias de idade, foram amostrados aleatoriamente um macho e uma fêmea por boxe, num total de cinco boxes por híbrido. Entre híbridos, Hb3 apresentou maior peso vivo em todas as idades e, entre sexos, os machos foram mais pesados. A força máxima na flexão foi maior para os machos e, para os híbridos, Hb3 foi maior que Hb1 e igual a Hb2 aos 42 dias. O piores resultados de tenacidade e resistência à flexão foram observados nos machos híbridos Hb2, que não diferiram dos Hb3 quanto à resistência à flexão aos 42 dias nem quanto à tenacidade medida em todas as idades, o que caracteriza baixa qualidade óssea dos híbridos Hb3 e machos. Devem-se considerar aspectos biomecânicos como tenacidade e resistência à flexão para corrigir e evitar o aparecimento das desordens ósseas provenientes do aumento de peso em frangos de corte.

The objective of the experiment was to determine the biochemical, morphometrics and biomechanical aspects of femur bones of broilers. It was used six hundred male and female broilers at one day of age from three different lines (Hb1 and Hb2 - UFV and Hb3 - commercial). They were fed ad libitum on starter (1 to 21 days), grower (22 to 35 days) and finisher (36 to 42 days) rations. The experimental design was completely randomized, in a factorial arrangement 3 × 2 (three lines and two sexes) with 5 replicates and 10 birds per experimental unit (box). The weight, length, cross-sectional area, moment of inertia, maximum load, modulus of elasticity, bending strength, collagenous and non collagenous proteins and body weight of the broilers were evaluated in the femur. At 21, 28, 35 and 42 days of age, one male and one female of each line were randomly selected per box, in a total of five boxes per line. Among lines, Hb3 presented higher superior body weight in all ages, and among sexes, the males were heavier. The strength of maximum load was higher for the males and lines HB3 was higher than HB1and equal to HB2 at 42 days of age. The worst results of elasticity and bending strength at 42 days of age were observed in males from line HB2, which did not differ from HB3 regarded to bending at 42 days of age and to elasticity measured in all ages, which characterizes low bone quality of the males and line HB3. Biomechanical aspects of femurs bones, as modulus of elasticity and bending strength, to correct and avoid bone damages of broilers due to their heavier weight.