Evaluation of the Pozzolanic Activity of Uncontrolled-Combusted Sewage Sludge Ash

[EN] Waste management is a crucial issue facing modern society. The generation of sewage sludge is increasing annually due to the urbanization and improvement of sanitation systems of cities. The construction sector has emerged as a solution for the elimination of waste due to the enormous volume of materials that this sector can absorb. This paper evaluates the pozzolanic activity of sewage sludge ash (USSA) obtained following an uncontrolled-combustion process, a simple and economic procedure. Compressive strength of Portland cement/USSA mortars with 5%¿25% by weight USSA were evaluated. Calcium hydroxide/USSA and Portland cement/USSA pastes were chemically and physically characterized through thermogravimetric/differential-thermogravimetric (TG/DTG), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses. The increase in the replacement of Portland cement by USSA is associated with an increase in the compressive strength of mortars. These values for USSA containing mortars cured for 90 days were in the range of 49.6¿55.4 MPa, higher than the one reached by the reference mortar. According to the microstructural analysis, the increment on the compressive strength can be attributed to the formation of hydrated products (C¿S¿H, C¿A¿S¿H, and C¿A¿H) by the pozzolanic reaction of USSA.This research was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior-Brasil (Capes)Finance Code 001, and Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) (Processo Nos. 309015/2015-4 and 478057/2013-0). Thanks go to the Scanning Electron Microscopy Service of FEIS/UNESP, Servico Municipal Autonomo de Agua e Esgoto (SEMAE) from the Sao Jose do Rio Preto city (Sao Paulo, Brazil).Istuque, DB.; Reig, L.; Soriano Martinez, L.; Borrachero Rosado, MV.; Pinheiro Melges, JL.; Akasaki, JL.; Paya Bernabeu, JJ.... (2021). Evaluation of the Pozzolanic Activity of Uncontrolled-Combusted Sewage Sludge Ash. Journal of Materials in Civil Engineering. 33(6):1-12. https://doi.org/10.1061/(ASCE)MT.1943-5533.000376511233

Cinza de casca de arroz (CCA) altamente reativa: método de produção e atividade pozolânica

This paper presents a production method for high reactive rice husk ash (RHA) by means of an uncontrolled combustion process. The production process and pozzolanic activity of RHA are described. The pozzolanic reactivity of RHA was determined by Thermogravimetric Analysis (TGA). Additionally, mortars with different percentages of RHA (5%, 10% and 15%) were prepared to verify their influence on mechanical strength. The results show that RHA presents high pozzolanic reactivity and can be used as an alternative source of silica fume (SF).Mitsuuchi Tashima, M.; Fioriti, CF.; Akasaki, JL.; Paya Bernabeu, JJ.; Cirqueira Sousa, L.; Pinheiro Melges, JL. (2012). Cinza de casca de arroz (CCA) altamente reativa: método de produção e atividade pozolânica. Ambiente Construído. 12(2):151-163. http://hdl.handle.net/10251/56851S15116312

Utilização de resíduos de borracha de pneu na fabricação de tubos de concreto

[EN] The concrete pipes are usually used in systems of drainage, of sewage collection and of potable water supply. In relation to the concern of sustainability in the process of manufacturing concrete pipes, the addition of the tire rubber residue into the concrete appears as a possibility to mitigate environmental impacts, since this residue is abundantly generated during the retreading process. Different contents of tire rubber residue were added to the concretes that were used to manufacture pipes with nominal diameter and length of, respectively, 600 mm and 1.5 m. It was assumed that these pipes would be intended to be a part of drainage systems for rainwater. The pipes made with these different concrete mixtures were subjected to a diametral compression test and also to a water absorption test. These tests are detailed by the brazilian standard NBR 8890 (ABNT, 2007). The results showed that the tire rubber residue has potential to be added to the concrete used in the production of pipes.Queiroz, RM.; Trentin, TFS.; Fugii, AP.; Mitsuuchi Tashima, M.; Pinheiro Melges, JL.; Akasaki, JL.; Paya Bernabeu, JJ. (2014). Utilização de resíduos de borracha de pneu na fabricação de tubos de concreto. Universitas (Araçatuba). 6:32-48. http://hdl.handle.net/10251/767823248

Possibilities of reusing sugar cane straw ash in the production of alternative binders

[EN] Sugar cane production is increasing in Brazil due the demand in manufacturing sugar and alcohol. During production process, several wastes are generated, such as sugar cane straw. After a burning process of this waste material, sugar cane straw ash (SCSA) is obtained, and may be used in the production of alternative binders. The aim of this paper is to assess the possibility of reuse SCSA as supplementary cementitious material in blended Portland cement mortars and as raw material in the production of alkali-activated binders. Blended Portland cement mortars were prepared using 0%, 20% and 30% of SCSA in replacement of Portland cement. For alkali-activated mortars, the activating solution is based on sodium hydroxide (NaOH) solution and different Slag/SCSA proportions in mass were assessed: 100/0, 75/25 and 50/50. Mechanical strength of mortars cured at room temperature was tested for 7 and 28 curing days. The results confirm that enhanced mechanical properties can be obtained for both alternative binders using SCSA on its composition.Bassan De Moraes, JC.; Queiroz, DCDA.; Akasaki, JL.; Pinheiro Melges, JL.; Borrachero Rosado, MV.; Paya Bernabeu, JJ.; Mitsuuchi Tashima, M. (2016). Possibilities of reusing sugar cane straw ash in the production of alternative binders. Key Engineering Materials. 668:304-311. doi:10.4028/www.scientific.net/KEM.668.304S304311668SNIC - Sindicato Nacional da Indústria do Cimento. Consumo Mensal de 2013. Information on http: /www. snic. org. br/numeros_dinamico. asp. (11/03/2014).FICEM - Inter-American Cement Federation. Statistical Report 2013. Information on http: /www. ficem. org/estadisticas/statiscal_report_2013. pdf. (11/03/2014).X. Guo, H. Shi, W.A. Dick. Compressive strength and microstructural characteristics of class C fly ash geopolymer. Cem Concr Compos. 32 (2010) 142–147.J.H. Sharp, E.M. Gartner, D.E. Macphee. Novel cement system (sustainability). Session 2 of the Fred Glasser cement science symposium. Adv Cem Res. 22(4) (2010) 195–202.P. C. Hewlett. Lea's Chemistry of Cement and Concrete, fourth ed., ELSEVIER, London, (2008).J. Payá, J. Monzó, M. V. Borrachero, E. Peris-Mora, L. M. Ordóñez. Studies on crystalline rice husk ashes and the activation of their pozzolanic properties. Waste Manage. 1 (2000) 493-503.G. C. Cordeiro, R. D. Toledo Filho, L. M. Tavares, E. M. R. Fairbairn. Ultrafine grinding of sugar cane bagasse ash for application as pozzolanic admixture in concrete. Cem Concr Res. 39 (2008) 110-115.G. C. Cordeiro, L. M. Toledo Filho, E. M. R. Fairbairn. Effect of calcination temperature on the pozzolanic activity of sugar cane bagasse ash. Cons Build Mater. 23 (2009) 3301-3303.V. N. Castaldelli, J. L. Akasaki, J. L. P. Melges, M. M. Tashima, L. Soriano, M. V. Borrachero, J. Monzó, J. Payá. Use of Slag/Sugar Cane Bagasse Ash [SCBA] Blends in the Production of Alkali-Activated Materials. Mater. 6 (2013) 3108-3127.F. P. Torgal, J. C. Gomes, S. Jalali. Alkali-activated binders: A review Part 1. Historical background, terminology, reaction mechanisms and hydration products. Constr Build Mater. 22 (2008) 1305-1314.M. Lizcano, H. S. Kim, S. Basu, M. Radovi. Mechanical properties of sodium and potassium activated metakaolin-based geopolymers. J Mater Sci. 47 (2012) 2607-2616.N. Ranjbar, M. Mehrali, U. J. Alengaram, H. S. C Metselaar, M. Z. Jumaat. Compressive strength and microstructural analysis of fly ash/palm oil fuel ash based geopolymer mortar under elevated temperatures. Constr Build Mater. 65 (2014) 114-121.S. Onisei, Y. Pontikes, T. van Gerven, V.N. Angelopoulos, T. Velea, V. Predica, P. Moldovan. Synthesis of inorganic polymers using fly ash and primary lead slag. J Hazard Mater. 205–206 (2012) 101–110.S.A. Bernal, E. Rodríguez, R. Mejía de Gutiérrez, M. Gordillo, J.L. Provis. Mechanical and thermal characterisation of geopolymers based on silicate-activated metakaolin/slag blends. J Mater Sci. 46 (2011) 5477–5486.M. L. C. Ripoli. Utilização do material remanescente de colheita de cana-de-açúcar [Saccharun spp] – Equacionamento dos balanços energético e econômico (In portuguese). 150 pages. Habilitation Thesis – Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, (1991).M. L. C. Ripoli, C. A. Gamero. Palhiço de cana-de-açúcar: ensaio padronizado de recolheimento por enfardamento cilíndrico. Energia na Agricultura (In portuguese). 22(1) (2007) 75-93.Associação Brasileira de Normas Técnicas. NBR 7214 – Areia para ensaio de cimento (In portuguese). 4 pages. Rio de Janeiro, (2012).A. Guzmán, C. Gutiérrez, V. Amigó, R. Mejia de Gutiérrez, S. Delvasto. Pozzolanic evaluation of the sugar cane leaf. Materiales de Construcción. 61 (2011) 213-225.M. M. Tashima. Producción y caracterización de materiales cementantes a partir del Silicoaluminato Cálcico Vítreo (VCAS) (In spanish). 454 pages. PhD Thesis - Universitat Politècnica de València, Valencia, (2012)

Estudo das propriedades mecânicas do concreto com adição de cinza de casca de arroz

The thermal curing is a process used to accelerate the hydration reactions of the Portland cement in mortar and concrete elements, in order to achieve gains in mechanical strength at early ages, since the temperature acts on the degree of these reactions. On this way, it is important to assess the mechanical behavior of concretes with mineral additions. The rice husk ash (RHA) is a residue that lies among the most studied additions in the concrete composition. The reuse of RHA besides reduce the environmental problems, can cause an increment on the mechanical strength of mortars and concrete, even when is used in partial substitution of Portland cement. This paper presents experimental results of the compressive strength, of the tensile strength (obtained by the split test), and of the modulus of elasticity for concrete prepared with RHA, incorporated into the mixture at dosages of 5% and 10% (by mass), in substitution of the cement. The RHA was produced through the uncontrolled burning of rice husk. The concrete mixtures were defined from an evaluation of the mechanical properties of specimens that were made with and without the addition of RHA. The process of thermal steam curing of the concrete was developed in cycles of 6 hours, at a constant temperature of 80 degrees C. The results showed higher strengths for specimens that were made with the addition of RHA.A cura térmica é um processo utilizado para acelerar as reações de hidratação do cimento Portland, em argamassas e em concretos, com objetivo de se obter ganhos de resistência mecânica nas primeiras idades, uma vez que a velocidade das reações químicas de hidratação aumenta com o aumento da temperatura. Nesse sentido, é importante estudar o comportamento de concretos que possuem adições minerais em sua composição. Dentre as adições mais estudadas na composição do concreto encontra-se a Cinza de Casca de Arroz (CCA). Além de ser uma forma de destinar adequadamente este resíduo, e, consequentemente, reduzir os impactos ambientais, tem como principal vantagem os ganhos de resistência, mesmo quando se diminui a quantidade de cimento na mistura. Este trabalho apresenta resultados experimentais de resistência à compressão axial, de resistência à tração por compressão diametral e do módulo de elasticidade para concretos elaborados com CCA, incorporada à mistura em dosagens de 5% e 10% (em massa), em substituição ao cimento. A CCA foi produzida por meio da queima não controlada da casca do arroz. Os traços de concreto foram definidos a partir de uma avaliação das propriedades mecânicas de corpos de prova de argamassa com e sem adição de CCA, tendo sido adotados os que apresentaram as maiores resistências. O processo de cura térmica a vapor dos concretos foi desenvolvido em ciclos de 6 horas, a uma temperatura constante de 80°C. Os resultados mostram um ganho de resistência das amostras com a adição de CCA.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq