Pozzolanic evaluation of the sugar cane leaf

This paper presents the results of the evaluation of the sugarcane leaf, burnt under controlled conditions in order to obtain a reactive ash with pozzolanic properties. Chemical analysis, amorphousity and surface structure of the sugar cane straw ash (SCSA) were studied by X-ray diffraction, X-ray fluorescence spectroscopy and scanning electron microscope (SEM). The results of this research showed that SCSA has significant presence of amorphous material and a high content of silica (81.0%). The pozzolanic activity of the SCSA was evaluated by the Fratini test and the pozzolanic activity index. In order to interpretate the pozzolan activity, the Feret method was used. It is conclude that the SCSA presents pozzolanic characteristics for blending Portland cement.The authors wish to thank Valle University, Colombia, the Centre for New Materials Excellence (CENM), the CYTED Programme for Research Project Coordination (307ac0307, agroindustrial by-products - sustainable source of construction materials (VALORES)) and the Polytechnic University of Valencia's Materials Technology Institute for the support provided for this study.Guzmán, A.; Gutierrez, C.; Amigó Borrás, V.; Mejia De Gutierrez, R.; Delvasto, S. (2011). Valoración puzolánica de la hoja de la caña de azúcar. Materiales de Construcción. 61:213-225. https://doi.org/10.3989/mc.2011.54809S2132256

Cementos híbridos basados en la activación alcalina de subproductos del carbón

Este estudio se propuso la producción de un material cementicio alternativo de bajo impacto ambiental a partir de la evaluación de dos subproductos de la combustión del carbón. Se elaboraron dos cementos híbridos basados en la activación alcalina de una ceniza volante (FA) y una escoria de parrilla (BS) y adicionados con cemento portland (OPC) hasta en un 30%. FA y BS contienen hasta un 16% de inquemados. Para la optimización de la resistencia a la compresión se utilizó la Metodología de Superficie de Respuesta (MSR). El geopolímero BS alcanzo alta resistencia a la compresión (>100 MPa a 28 días) y el geopolímero FA reporto 30 MPa al aplicar curado térmico. La adición de OPC contribuyo a modificar el método de curado. En el caso del hibrido basado en FA (HFA), se observó un incremento significativo en la resistencia a niveles hasta de 65 MPa a 28 días sin aplicar el curado térmic0This study focuses on the production of an alternative cementitious material with low environmental impact through the evaluation of two-coal combustion by-products. Hybrid cements based on the alkali activation of fly ash, (FA) and boiler slag (BS) blend with a proportion of Portland cement (OPC) up to 30% were produced. FA and BS contain an unburned material up to 16%. Response Surface Methodology (RSM) was used to optimize the compressive strength. BS geopolymer achieved high compressive strength (>100 MPa at 28 days) and FA geopolymer reached 30 MPa with thermal curing. The addition of OPC helped modify the curing method. In the case of hybrid based on FA (HFA), there was a significant increase in the compressive strength with levels ranging up to 65 MPa at 28 days without requiring a thermal curin

Mechanical and thermal characterisation of geopolymers based on silicate-activated metakaolin/slag blends

[EN] This article assesses the effect of mix design parameters on the compressive strength and thermal performance of alkali silicate-activated blends of metakaolin (MK) and granulated blast furnace slag (GBFS). A strong interrelationship between the effects of activator composition and the GBFS/(GBFS + MK) ratio is identified through statistical analysis of compressive strength data. Pastes formulated with higher SiO 2/Al 2O 3 molar ratios show improvements in mechanical strength with increasing GBFS addition, associated with the formation of a structure comprising coexisting aluminosilicate 'geopolymer' gel and Ca-rich Al-substituted silicate hydrate (C-(A)-S-H) reaction products. The inclusion of GBFS in MK-based geopolymers seems also to improve their performance when exposed to high temperatures, as higher residual compressive strengths are reported for these mixtures compared to solely MK-based systems. Only slight differences in shrinkage behaviour are observed at temperatures of up to 600 °C with the inclusion of GBFS; however, slag-blended pastes exhibit enhanced stability at temperatures exceeding 800 °C, as no variation in the compressive strength and no additional shrinkage are identified. These results suggest that nanostructural modifications are induced in the gel by the inclusion of GBFS into MK-based geopolymers, improving the overall performance of these materials. © 2011 Springer Science+Business Media, LLC.This study was sponsored by Universidad del Valle (Colombia), Instituto Colombiano para el Desarrollo de la Ciencia y Tecnologia "Francisco Jose de Caldas" (COLCIENCIAS) and the Center of Excellence of Novel Materials (CENM). The participation of JLP was funded by the Australian Research Council (ARC), including partial funding through the Particulate Fluids Processing Centre, a Special Research Centre of the ARC.Bernal, SA.; Rodríguez Martínez, ED.; Mejía De Gutiérrez, R.; Gordillo, M.; Provis, JL. (2011). Mechanical and thermal characterisation of geopolymers based on silicate-activated metakaolin/slag blends. Journal of Materials Science. 46(16):5477-5486. doi:10.1007/s10853-011-5490-zS547754864616Shi C, Krivenko PV, Roy DM (2006) Alkali-activated cements and concretes. Taylor & Francis, Abingdon, UKDavidovits J (1991) J Thermal Analysis 37:1633Palomo A, Glasser FP (1992) Brit Ceram Trans J 91:107Provis JL, van Deventer JSJ (eds) (2009) Geopolymers: Structures, Processing, Properties and Industrial Applications, Woodhead. Cambridge, UKPerera DS, Uchida O, Vance ER, Finnie KS (2007) J Mater Sci 42(9):3099. doi: https://doi.org/10.1007/s10853-006-0533-6Provis JL, Duxson P, van Deventer JSJ (2010) Adv Powder Technol 21(1):2Lecomte I, Henrist C, Liegeois M, Maseri F, Rulmont A, Cloots R (2006) J Eur Ceram Soc 26:3789Lloyd RR (2009) Accelerated ageing of geopolymers. In: Provis JL, van Deventer JSJ (eds) Geopolymers: Structures, Processing, Properties and Industrial Applications. Woodhead, Cambridge, UK, p 139Alonso S, Palomo A (2001) Cem Concr Res 31:25Alonso S, Palomo A (2001) Mater Lett 47(2):55Cheng TW, Chiu JP (2003) Miner Eng 16:205Yip CK, van Deventer JSJ (2003) J Mater Sci 38:3851. doi: https://doi.org/10.1023/A:1025904905176Yip CK, Lukey GC, van Deventer JSJ (2005) Cem Concr Res 35:1688Yip CK, Lukey GC, Provis JL, van Deventer JSJ (2008) Cem Concr Res 38(4):554Buchwald A, Hilbig H, Ch Kaps (2007) J Mater Sci 42:3024. doi: https://doi.org/10.1007/s10853-006-0525-6Buchwald A, Tatarin R, Stephan D (2009) J Mater Sci 44:5609. doi: https://doi.org/10.1007/s10853-009-3790-3Bernal SA, Mejia de Gutiérrez R, Provis JL, Rose V (2010) Cem Concr Res 40(6):898Bernal SA, Provis JL, Rose V, Mejía de Gutiérrez R (2011) Cem Concr Compos 33(1):46Yip CK, Provis JL, Lukey GC, van Deventer JSJ (2008) Cem Concr Res 30:979Sakulich AR, Anderson E, Schauer C, Barsoum MW (2009) Constr Build Mater 23:2951García-Lodeiro I, Fernández-Jiménez A, Blanco MT, Palomo A (2008) J Sol-Gel Sci Technol 45:63García-Lodeiro I, Macphee DE, Palomo A, Fernández-Jiménez A (2009) FTIR analysis. Cem Concr Res 39:147Hong S-Y, Glasser F (1999) Cem Concr Res 29(12):1893Hong S-Y, Glasser F (2002) Cem Concr Res 32(7):1101Barbosa VFF, MacKenzie KJD (2003) Mater Lett 57:1477Barbosa VFF, MacKenzie KJD (2003) Mater Res Bull 38:319Rahier H, Wastiels J, Biesemans M, Willem R, Van Assche G, Van Mele B (2007) J Mater Sci 42:2982. doi: https://doi.org/10.1007/s10853-006-0568-8Kong DLY, Sanjayan JG, Sagoe-Crentsil K (2008) J Mater Sci 43:824. doi: https://doi.org/10.1007/s10853-007-2205-6Duxson P, Lukey GC, van Deventer JSJ (2007) J Mater Sci 42:3044. doi: https://doi.org/10.1007/s10853-006-0535-4Duxson P, Lukey GC, van Deventer JSJ (2006) J Non-Cryst Solids 352:5541Comrie DC, Kriven WM (2003) Ceram Trans 153:211Bell JL, Sarin P, Provis JL, Haggerty RP, Driemeyer PE, Chupas PJ, van Deventer JSJ, Kriven WM (2008) Chem Mater 20(14):4768Kovalchuk G, Krivenko PV (2009) . In: Provis JL, van Deventer JSJ (eds) Geopolymers: Structures, Processing, Properties and Industrial Applications. Woodhead, Cambridge, UK, p 229Palacios M (2008) Ph.D thesis, Universidad Autónoma de Madrid, SpainBernal S, Mejía de Gutiérrez R, Rodríguez E, Esguerra J (2008) In: Proceedings of the 23rd International Conference on Solid Waste Technology and Management. Philadelphia, USAGuerrieri M, Sanjayan J, Collins F (2010) Mater Struct 43:765Zuda L, Černý R (2009) Cem Concr Compos 31(4):263Rodríguez E, Mejía de Gutiérrez R, Bernal S, Gordillo M (2009) Rev Latin Metal Mater S1(2):595Rodríguez ED (2008) Efecto de las relaciones Si/Al/Na/Ca en materiales geopolimericos basados en metacaolin. M.Eng. thesis, Universidad del Valle, Cali, ColombiaBernal S, Gordillo M, Mejía de Gutiérrez R, Rodríguez E, Delvasto S, Cuero R (2009) Rev Fac Ing Univ Antioquia 49:112Duxson P, Provis JL, Lukey GC, Mallicoat SW, Kriven WM, van Deventer JSJ (2005) Colloids Surf A 269(1–3):47Provis JL, van Deventer JSJ (2007) Chem Eng Sci 62(9):2309García-Lodeiro I, Fernández-Jiménez A, Palomo A, Macphee DE (2010) Cem Concr Res 40:27Provis JL, Rose V, Bernal S, van Deventer JSJ (2009) Langmuir 25(19):11897Cabrera J, Frías Rojas M (2001) Cem Concr Res 31:177Frías M, Cabrera J (2001) Cem Concr Res 31:519Provis JL, Yong SL, Duxson P, van Deventer JSJ (2008) In: 3rd International symposium on non-traditional cement and concrete, Brno, Czech Republic, p 589Duxson P, Lukey GC, Separovic F, van Deventer JSJ (2005) Ind Eng Chem Res 44(4):832Felsche J, Luger S (1987) Thermochimica Acta 118:35Rowles M, O’Connor B (2003) J Mater Chem 13:1161Alarcon-Ruiz L, Platret G, Massieu E, Ehrlacher A (2005) Cem Concr Res 35(3):609Wang S-D, Scrivener KL (1995) Cem Concr Res 25(3):561Wang S-D, Scrivener KL (2003) Cem Concr Res 33:769Richardson IG, Brough AR, Groves GW, Dobson CM (1994) Cem Concr Res 24(5):813Fernández-Jiménez A, Puertas F, Sobrados I, Sanz J (2003) J Am Ceram Soc 86(8):1389Fernández-Jiménez A, Pastor JY, Martín A, Palomo A (2010) J Amer Ceram Soc 93(10):3411Cincotto MA, Melo AA, Repette WL (2003) In: Proceedings of the 11th International Congress on the Chemistry of Cement (ICCC), Durban, South Africa, p 1878Duxson P, Lukey GC, van Deventer JSJ (2006) Langmuir 22(21):8750Zhang Z, Yao X, Zhu H (2010) Appl Clay Sci 49:1Dombrowski K, Buchwald A, Weil M (2007) J Mater Sci 42(9):3033. doi: https://doi.org/10.1007/s10853-006-0532-

International Nosocomial Infection Control Consortiu (INICC) report, data summary of 43 countries for 2007-2012. Device-associated module

We report the results of an International Nosocomial Infection Control Consortium (INICC) surveillance study from January 2007-December 2012 in 503 intensive care units (ICUs) in Latin America, Asia, Africa, and Europe. During the 6-year study using the Centers for Disease Control and Prevention's (CDC) U.S. National Healthcare Safety Network (NHSN) definitions for device-associated health care–associated infection (DA-HAI), we collected prospective data from 605,310 patients hospitalized in the INICC's ICUs for an aggregate of 3,338,396 days. Although device utilization in the INICC's ICUs was similar to that reported from ICUs in the U.S. in the CDC's NHSN, rates of device-associated nosocomial infection were higher in the ICUs of the INICC hospitals: the pooled rate of central line–associated bloodstream infection in the INICC's ICUs, 4.9 per 1,000 central line days, is nearly 5-fold higher than the 0.9 per 1,000 central line days reported from comparable U.S. ICUs. The overall rate of ventilator-associated pneumonia was also higher (16.8 vs 1.1 per 1,000 ventilator days) as was the rate of catheter-associated urinary tract infection (5.5 vs 1.3 per 1,000 catheter days). Frequencies of resistance of Pseudomonas isolates to amikacin (42.8% vs 10%) and imipenem (42.4% vs 26.1%) and Klebsiella pneumoniae isolates to ceftazidime (71.2% vs 28.8%) and imipenem (19.6% vs 12.8%) were also higher in the INICC's ICUs compared with the ICUs of the CDC's NHSN