PSI - Issue 11

Bárbara Belén Raggiotti et al. / Procedia Structural Integrity 11 (2018) 36–43 Raggiotti et al./ Structural Integrity Procedia 00 (2018) 000 – 000

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8. Conclusions

The physico-chemical characterization performed for natural zeolite makes it possible to classify this material as zeolite clinoptilolite-Na; although it does not adjust exactly to the maximum limit of SO 3 as per the type of pozzolan described in ASTM C618 Standard (2015), it can be used as a material with pozzolanic characteristics in Portland cement mixtures. This was confirmed by the results obtained in the second experimental stage of the mechanical resistance and durability assays of the concretes. Zeolite's rough and porous structure, as well as its large surface area, create a structure of the mixture pastes with zeolite that contain more complex forms and vacuums than the master mixture caused by the growth of the crystalline structure in all directions (Yılmaz et al ., 2007); a phenomenon that manifests itself in a loss of consistency of the mixtures as the incorporation of zeolite is increased, as could be observed in the Abrams Cone assay. In the mechanical assays, the use of zeolite contributes to the development of resistance in concretes over longer periods of time, showing its activity at ages of over 28 days. The difference in behavior between concretes with different cements stands out, mainly when durability indicators are analyzed. In this case we find more porous mixtures with compound Portland cement. The importance of the composition of the cement becomes evident, and the way it interacts and reacts to the zeolite added. The durability properties were generally achieved satisfactorily. The greatest effectiveness of applying zeolite was observed in mixtures with normal Portland cement. Lastly, it should be clarified that natural zeolites have different chemical properties, because of which it is necessary to carefully characterize them before using them as admixtures in cement mixes. The zeolite studied herein, Clinoptilolite-Na, fulfilled the three functions for which admixtures are used in Portland cement mixes. An economic function, as the amount of cement used in the mix was reduced, an ecological function, as an available material was used which has no use in the market and would otherwise have accumulated and become waste from the mining industry, and a technological function, as it improved properties of concretes. Therefore the zeolite proposed may be applied as a pozzolan in structural concretes improving its properties (Raggiotti, 2015). Agosto, M.F., 2012. Estudio de zeolitas procedentes de depósitos Argentinos. Aspectos tecnológicos que posibiliten su aplicación en agroindustria y contralor ambiental. Tesis Doctoral. Universidad nacional de La Plata. Facultad de ciencias exactas. Departamento de química. 185 pp. Ahmadi, B, & Shekarchi, M., 2010. Use of natural zeolite as a supplementary cementitious materials. Cement & Concrete Comp osites, 32: 34 – 141. Chung, F.H., 1974. Quantitative interpretation of x - ray diffraction patterns of mixtures I. Matrix - flushing method for quantitative multicomponent analysis. J. Appl Crystallogr, 7(6):519 –25. CIRSOC 201., 2005. Reglamento Argentino de Estructuras de Hormigón. INTI. Dal Molin, D.C.C., 2005. En Concreto, ensino, pesquisa e realizações, Cap 12. pp 345. Vol 1, ISBN: 85 - 98576 -04- 2. IBRACON. Giannetto Pace G., Montes Rendón A. & Rodriguez Fuentes, G., 2000. Zeolitas: Características, Propiedades y Aplicaciones Industriales, Innovación Tecnológica. Pp 187 - 205. Caracas. Editorial. Malhotra, V.M. & Mehta, P.K., 1996. Pozzolanic and cementitious materials. Advances in Concrete Technology, Vol 1, Gorgon and Breach Publishers. Najimi, M., Sobhani, J., Ahmadi, B. & Shekarchi, M., 2012. An experimental study on durability properties of concrete containing zeolite as a highly reactive pozzolan. Construction and Building Materials, 35: 1023–1033. Perraki, T., Kontori, E., Tsivilis, S. & Kakali, G., 2010. The effect of zeolite on the properties and hydration of blended cements. Cement and Concrete Composites, 32. doi: 10.1016/j.cemconcomp.2009.10.004. Poon, C.S., Lam, L., Kou, S.C. & Lin, Z.S., 1999. A study on the hydration rate of natural zeolite blended cement paste. Construction and Building Materials, 13: 427 – 432. Raggiotti, B.B., 2015. Hormigones con adiciones activas: diseño, optimización y caracterización con criterio de sustentabilidad. Tesis de doctorado. Universidad Tecnológica Nacional. Córdob a, Argentina. Rahhal, V. & Eperjeci, L., 2012. Ese material llamado hormigón. Cap 3: Adiciones minerles. Pp 79. ISBN: 978 - 987 - 21660 -5-2 Rosell, M., Galloso, R. & Calvo, B., 2006. Zeolita como aditivo mineral activo en hormigones de altas prestaciones. Boletín Geológico y Minero 117 (4): 783 - 792. ISSN: 0366 - 0176. Yilmaz, B., Uçar, A., Öteyaka, B. & Uz, V., 2007. Properties of zeolitic tuff (clinoptilolite) blended portland cement. Building and Environment, 42(11), 38083815. doi: 10.1016/j.buildenv.2006.11.006 References