PSI - Issue 11

Iara Silva et al. / Procedia Structural Integrity 11 (2018) 130–137

137

Iara Silva et al./ Structural Integrity Procedia 00 (2018) 000 – 000

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Through the recovery treatment of cracked sleepers, along with repairs of corners breaks and, to a lesser extent, misaligned fastening anchors, it was possible to recover about 8,000 sleepers, identified and stored, awaiting installation. The total expected recovery includes the approximate amount of 12,000 sleepers, responsible for avoiding the disposal of approximately 4,800 tons of concrete and over 160 tons of steel. 9. Conclusions The standard NBR 11709 (2015) recommends 350 kg the minimum cement per cubic meter of concrete. The production of a sleeper requires approximately 0.160 m³ of concrete, therefore a minimum of 56 kg of cement is required for each manufactured sleeper. The production of Portland cement, used to manufacture sleepers and civil construction in general, has a high impact in terms of greenhouse gas emissions, with carbon dioxide (CO2) being responsible for 6% of CO2 emissions in the world (WBCSD (2012)). The national average of carbon dioxide emission indicates that 600 kg of CO2 are emitted for each ton of cement produced. (FAPESP (2016)). This method of recovery has contributed to avoid the disposal of approximately 12,000 sleepers, whose production requires a minimum quantity of 672 tons of cement, which results in emission of more than 400 tons of CO2 resulting from cement production. In addition to the waste of the materials themselves, such as steel, for example, and all the energy used for the manufacture of sleepers and the exploitation of raw materials, which would cause economic and mainly environmental damage, given the worrying scenario around the global effects and the measures being taken to mitigate these effects. Therefore, the recovery of cracks in concrete sleepers through the technique of painting crystallization proved to be a technically feasible procedure, since it was able to seal the non-structural cracks that appeared in the sleepers during the manufacturing process. The sleepers recovered and classified for application on secondary lines represent financial and environmental gains, a significant reduction in the number of rejected pieces, a reduction of costs for the manufacturer and, consequently, for the railroad, by avoiding the waste of materials and energy expended in sleepers’ produc tion, and it is important to always evaluate the possibility of repair and use. The next steps are to install the sleepers on the low traffic and speed secondary lines and to monitor for a period of approximately one year or 80 MGT (Million gross tons) transported to verify the behavior of these sleepers, through actual efforts resulting from the passage of trains as well as the weather and thermal variations that may occur. And also, to deepen study and knowledge about other prestressed concrete sleepers recovery procedures. Acknowledgements To CAVAN Pre-moldado S.A., VALE S.A. - Carajas Railway (EFC) and the Federal Institute of Education, Science and Technology of Maranhao (IFMA) for all the support and assistance provided. References Associação Brasileira de Normas Tecnicas, ABNT NBR 11709: Dormente de concreto – Projeto, materiais e componentes, Rio de Janeiro, 2015. P. S. S. Bastos, Análise experimental de dormentes de concreto protendido reforçados com fibras de aço, Doctoral thesis, School of Engineering of Sao Carlos, University of Sao Paulo, Department of Structural Engineering, Sao Carlos, 1999. P. S. S. Bastos, L.M. Pinheiro, Dormentes de concreto protendido Reforçados com fibras de aço. Structural Engineering Notebooks, Sao Carlos, 2007, pp.117-150. H. L. Brina, Estradas de ferro 1, Editora UFMG, second ed., Belo Horizonte,1988. V.G Cappellesso, Uso de Impermeabilizante por Cristalização para Redução da Permeabilidade do Concreto. Course Conclusion Paper. School of Engineering, Federal University of Rio Grande do Sul, 2016. http://hdl.handle.net/10183/159626. (accessed 08 January 2018). D. Freire, Especialistas discutem papel da indústria do cimento nas emissões de CO2. Agency FAPESP, Sao Paulo, 2016. http://agencia.fapesp.br/especialistas_discutem_papel_da_industria_do_cimento_nas_emissoes_de_co2/23449/>. (accessed 14 January 2018). V. C. M. Souza, T. Ripper, Patologia, Recuperação e Reforço de estruturas de Concreto, Editora Pini, Sao Paulo, 1998. World Business Council for Sustainable Development – WBCSD, Diretrizes para o Relatório e Monitoramento das Emissões na Indústria de Cimento, Iniciativa para a Sustentabilidade do Cimento, Brasilia, v.2, 2012. American Railway Engineering and Manutenance Association, AREMA, Manual for Railway Engineering – Concrete Ties, 2013, v.1, chap. 30, 178p.