An investigation of the mechanisms for strength gain or loss of geopolymer mortar after exposure to elevated temperature

When fly ash-based geopolymer mortars were exposed to a temperature of 800 °C, it was found that the strength after the exposure sometimes decreased, but at other times increased. This paper shows that ductility of the mortars has a major correlation to this strength gain/loss behaviour. Specimens prepared with two different fly ashes, with strengths ranging from 5 to 60 MPa, were investigated. Results indicate that the strength losses decrease with increasing ductility, with even strength gains at high levels of ductility. This correlation is attributed to the fact that mortars with high ductility have high capacity to accommodate thermal incompatibilities. It is believed that the two opposing processes occur in mortars: (1) further geopolymerisation and/or sintering at elevated temperatures leading to strength gain; (2) the damage to the mortar because of thermal incompatibility arising from non-uniform temperature distribution. The strength gain or loss occurs depending on the dominant process

Pacific Islands Emergency Management Alliance (PIEMA) Project Mid-Term Review Report

This report presents findings of the Mid-Term Review of the Pacific Islands Emergency Management Alliance (PIEMA) project

Alkaline activation of ceramic waste materials

Ceramic materials represent around 45 % of construction and demolition waste, and originate not only from the building process, but also as rejected bricks and tiles from industry. Despite the fact that these wastes are mostly used as road sub-base or construction backfill materials, they can also be employed as supplementary cementitious materials, or even as raw material for alkali-activated binders This research aimed to investigate the properties and microstructure of alkali-activated cement pastes and mortars produced from ceramic waste materials of various origins. Sodium hydroxide and sodium silicate were used to prepare the activating solution. The compressive strength of the developed mortars ranged between 22 and 41 MPa after 7 days of curing at 65 C, depending on the sodium concentration in the solution and the water/binder ratio. These results demonstrate the possibility of using alkaliactivated ceramic materials in building applications.The authors are grateful to the Spanish Ministry of Science and Innovation for supporting this study through Project GEOCEDEM BIA 2011-26947, and also to FEDER funding. They also thank Universitat Jaume I for supporting this research through Lucia Reig's granted research stay.Reig Cerdá, L.; Mitsuuchi Tashima, M.; Soriano, L.; Borrachero Rosado, MV.; Monzó Balbuena, JM.; Paya Bernabeu, JJ. (2013). Alkaline activation of ceramic waste materials. Waste and Biomass Valorization. 4:729-736. https://doi.org/10.1007/s12649-013-9197-zS7297364Puertas, F., García-Díaz, I., Barba, A., Gazulla, M.F., Palacios, M., Gómez, M.P., Martínez-Ramírez, S.: Ceramic wastes as alternative raw materials for Portland cement clinker production. Cement Concrete Comp. 30(9), 798–805 (2008)Ministerio de Fomento de España, Catálogo de Residuos Utilizables en Construcción (2010). http://www.cedexmateriales.vsf.es/view/catalogo.aspx . Retrieved on 6 Dec 2012Stock, D.: World production and consumption of ceramic tiles. Tile Today 73, 50–58 (2011)Medina, C., Juan, A., Frías, M., Sánchez-de-Rojas, M.I., Morán, J.M., Guerra, M.I.: Characterization of concrete made with recycled aggregate from ceramic sanitary ware. Mater. Construcc. 61(304), 533–546 (2011)Pacheco-Torgal, F., Jalali, S.: Reusing ceramic wastes in concrete. Constr. Build. Mater. 24(5), 832–838 (2010)Lavat, A.E., Trezza, M.A., Poggi, M.: Characterization of ceramic roof tile wastes as pozzolanic admixture. Waste Manage. 29(5), 1666–1674 (2009)Nuran, A., Mevlut, U.: The use of waste ceramic tile in cement production. Cement Concrete Res. 30, 497–499 (2000)Pereira-de-Oliveira, L.A., Castro-Gomes, J.P., Santos, P.M.S.: The potential pozzolanic activity of glass and red-clay ceramic waste as cement mortars components. Constr. Build. Mater. 31, 197–203 (2012)Van Deventer, J.S.J., Provis, J.L., Duxson, P., Brice, D.G.: Chemical research and climate change as drivers in the commercial adoption of alkali activated materials. Waste Biomass Valor. 1, 145–155 (2010)van Deventer, J.S.J., Provis, J.L., Duxson, P., Lukey, G.C.: Reaction mechanisms in the geopolymeric conversion of inorganic waste to useful products. J. Hazard. Mater. A139, 506–513 (2007)Duxson, P., Fernández-Jiménez, A., Provis, J.L., Lukey, G.C., Palomo, A., van Deventer, J.S.J.: Geopolymer technology: the current state of the art. J. Mater. Sci. 42(9), 2917–2993 (2007)Bernal, S.A., Rodríguez, E.D., de Gutiérrez, R.M., Provis, J.L., Delvasto, S.: Activation of metakaolin/slag blends using alkaline solutions based on chemically modified silica fume and rice husk ash. Waste Biomass Valor. 3, 99–108 (2012)Fernández-Jiménez, A., Palomo, A., Criado, M.: Microstructure development of alkali-activated fly ash cement: a descriptive model. Cement Concrete Res 35, 1204–1209 (2005)Payá, J., Borrachero, M.V., Monzó, J., Soriano, L., Tashima, M.M.: A new geopolymeric binder from hydrated-carbonated cement. Mater. Lett. 74, 223–225 (2012)Kourti, I., Amutha-Rani, D., Deegan, D., Boccaccini, A.R., Cheeseman, C.R.: Production of geopolymers using glass produced from DC plasma treatment of air pollution control (APC) residues. J. Hazard. Mater. 176, 704–709 (2010)Puertas, F., Barba, A., Gazulla, M.F., Gómez, M.P., Palacios, M., Martínez-Ramírez, S.: Residuos cerámicos para su posible uso como materia prima en la fabricación de clínker de cemento Portland: caracterización y activación alcalina. Mater. Construcc. 56(281), 73–84 (2006)Reig, L., Tashima, M.M., Borrachero, M.V., Monzó, J., Payá, J.: Nuevas matrices cementantes generadas por Activación Alcalina de residuos cerámicos. II Simposio Aprovechamiento de residuos agro-industriales como fuente sostenible de materiales de construcción, November 8–9, Valencia, Spain, pp. 199–207 (2010)L. Reig, M.M. Tashima, M.V. Borrachero, J. Monzó, J. Payá: Residuos de ladrillos cerámicos en la producción de conglomerantes activados alcalinamente, I Pro-Africa Conference: Non-conventional Building Materials Based on Agroindustrial Wastes, October 18–19, Pirassununga, SP, Brazil, pp. 18–21 (2010)García Ten F.J. Descomposición durante la cocción del carbonato cálcico contenido en el soporte crudo de los azulejos. Tesis de doctorado, Departamento de Ingeniería química, UJI (2005)Baronio, G., Binda, L.: Study of the pozzolanicity of some bricks and clays. Constr. Build. Mater. 11(1), 41–46 (1997)Zanelli, C., Raimondo, M., Guarini, G., Dondi, M.: The vitreous phase of porcelain stoneware: composition, evolution during sintering and physical properties. J. Non-Cryst. Solids 357, 3251–3260 (2011)Carty, W.M., Senapati, U.: Porcelain-raw materials, processing, phase evolution, and mechanical behaviour. J. Am. Ceram. Soc. 81(1), 3–20 (1998)ASCER, COACV, COPUT, ITC-AICE, WEBER ET BROUTIN – CEMARKSA: Guía Baldosa Guía de la baldosa cerámica. IVE: Conselleria d’Obres Públiques, Urbanisme i Transports, 4ª Ed. Valencia (2003)Khater, H.M.: Effect of calcium on geopolimerization of aluminosilicate wastes. J. Mater. Civ. Eng. 24, 92–101 (2012)Bondar, D., Lynsdale, C.J., Milestone, N.B., Hassani, N., Ramezanianpour, A.A.: Effect of adding mineral additives to alkali-activated natural pozzolan paste. Constr. Build. Mater. 25, 2906–2910 (2011)Provis, J.L., Harrex, R.M., Bernal, A.S., Duxson, P., van Deventer, J.S.J.: Dilatometry of geopolymers as a means of selecting desirable fly ash sources. J. Non-Cryst. Solids 358, 1930–1937 (2012)Duxson, P., Provis, J.L., Lukey, G.C., Mallicoat, S.W., Kriven, W.M., van Deventer, J.S.J.: Understanding the relationship between geopolymer composition, microstructure and mechanical properties. Colloid Surf. A 269, 47–58 (2005)Tashima, M.M., Akasaki, J.L., Castaldelli, V.N., Soriano, L., Monzó, J., Payá, J., Borrachero, M.V.: New geopolymeric binder based on fluid catalytic cracking catalyst residue (FCC). Mater. Lett. 80, 50–52 (2012)Komnitsas, K., Zaharaki, D., Perdikatsis, V.: Geopolymerisation of low calcium ferronickel slags. J. Mater. Sci. 42, 3073–3082 (2007)Bernal, S.A., Gutierrez, R.M., Provis, J.L., Rose, V.: Effect of silicate modulus and metakaolin incorporation on the carbonation of alkali silicate-activated slags. Cement Concrete Res. 40, 898–907 (2010)Tashima, M.M. Produccion y caracterizacion de materiales cementantes a partir del silicoaluminato calcico vitreo (VCAS). Tesis de doctorado, Departamento de Ingeniería de la construcción y de proyectos de ingeniería civil, UPV (2012)Provis, J.L., van Deventer, J.S.J.: Geopolymerisation kinetics. 2. Reaction kinetic modelling. Chem. Eng. Sci. 62, 2318–2329 (2007

Synthetic Geopolymers for Controlled Delivery of Oxycodone: Adjustable and Nanostructured Porosity Enables Tunable and Sustained Drug Release

In this article we for the first time present a fully synthetic mesoporous geopolymer drug carrier for controlled release of opioids. Nanoparticulate precursor powders with different Al/Si-ratios were synthesized by a sol-gel route and used in the preparation of different geopolymers, which could be structurally tailored by adjusting the Al/Si-ratio and the curing temperatures. In particular, it was shown that the pore sizes of the geopolymers decreased with increasing Al/Si ratio and that completely mesoporous geopolymers could be produced from precursor particles with the Al/Si ratio 2∶1. The mesoporosity was shown to be associated with a sustained and linear in vitro release profile of the opioid oxycodone. A clinically relevant release period of about 12 h was obtained by adjusting the size of the pellets. The easily fabricated and tunable geopolymers presented in this study constitute a novel approach in the development of controlled release formulations, not only for opioids, but whenever the clinical indication is best treated with a constant supply of drugs and when the mechanical stability of the delivery vehicle is crucial

Comparative environmental life cycle analysis of stone wool production using traditional and alternative materials

The mineral wool sector represents 10 % of the total output tonnage of the glass industry. The thermal, acoustic and fire protection properties of mineral wool make it desirable for use in a wide range of economic sectors especially in the construction industry for the creation of low energy buildings. The traditional stone wool manufacturing process involves melting raw materials, in a coke-fired hot blast cupola furnace, fiberization, polymerization, cooling, product finishing and gas treatment. The use of alternative raw materials as torrefied biomass and sodium silicate, is proposed as an alternative manufacturing process to improve the sustainability of stone wool production, particularly the reduction of gas emissions (CO2 and SO2). The present study adopts a life cycle analysis (LCA) approach to measure the comparative environmental performance of the traditional and alternative stone wool production processes; process data are incorporated into a LCA model using SimaPro 8 software with the Ecoinvent version 3 life cycle inventory database. The CML 2000 and Eco-Indicator99 methods are used to estimate effects on different impact categories. The Minerals and Land use impacts in Eco-Indicator99 and the Eutrophication impact in CML2000 increase between 2 and 4 % for the alternative process instead of the traditional one. Similarly, the ecotoxicity-related impacts increase between 9 and 24 % with the use of the alternative process. However these increases are compensated by concomitant impact decreases in other categories of impact; consequently, the three areas of impact grouped by individual Eco-indicator 99 impacts, show environmental benefits improvements between 6 and 15 % when using the alternative process based on torrefied biomass and silicate instead of the traditional process based on coke and cement use

Calorimetric study of geopolymer binders based on natural pozzolan

This paper investigates the kinetics of geopolymerisation in an inorganic polymeric binder based on a natural pozzolan. The heat released by the exothermic geopolymerisation reaction process is monitored under isothermal temperature conditions, maintained in a differential scanning calorimeter using a water circulation cell. Calorimetric data are obtained isothermally at 65, 75, and 85 °C with various Na2O/Al2O3 and SiO2/Na2O molar ratios and in the presence and absence of small amounts of calcium aluminate cement (used as an efflorescence control admixture in these binder systems). The first stage of reaction, which is rapid and strongly exothermic, is shortened as the temperature increases. The total heat of reaction increases in the mixes containing calcium aluminate cement, but the apparent activation energy calculated using a pseudo-first-order reaction model is lower than without added calcium aluminate cement. At a constant overall SiO2/Na2O molar ratio, the apparent activation energy is decreased as the Na2O/Al2O3 molar ratio increases. Calcium aluminate cement, therefore, reduces the minimum energy required to initiate geopolymerisation reactions of this natural pozzolan and facilitates the progress of the reactions which lead to formation of a cementitious product

Alkali activation of vitreous calcium aluminosilicate derived from glass fiber waste

The properties and microstructure of alkali-activated (AA) vitreous calcium aluminosilicate (VCAS) are presented in this paper. VCAS is manufactured from a by-product of the glass fiber industry and has been activated using NaOH and KOH solutions. The microstructure and mechanical properties of AA VCAS pastes and mortars are reported. The results show that depending on the type and concentration of hydroxide solution used, mortar samples with compressive strengths up to 77 MPa can be formed after curing for three days at 65 °C. The research demonstrates the potential of VCAS to produce AA cements and the importance of alkali type and concentration in optimizing properties and microstructure.Mitsuuchi Tashima, M.; Soriano Martinez, L.; Borrachero Rosado, MV.; Monzó Balbuena, JM.; Cheeseman, CR.; Paya Bernabeu, JJ. (2012). Alkali activation of vitreous calcium aluminosilicate derived from glass fiber waste. Journal of Sustainable Cement-Based Materials. 1(3):83-93. doi:10.1080/21650373.2012.742610S839313Mahasenan N, Smith S, Humphreys K. The cement industry and global climate change: current and potential future cement industry CO2emissions. Greenhouse Gas Control Technologies – 6th International Conference. Oxford: Pergamon; 2003. p. 995–1000.Schneider, M., Romer, M., Tschudin, M., & Bolio, H. (2011). Sustainable cement production—present and future. Cement and Concrete Research, 41(7), 642-650. doi:10.1016/j.cemconres.2011.03.019WBCSD – World Business Council for Sustainable Development. Cement industry energy and CO2performance – Getting numbers right. Edited by WBCSD, Geneva-Switzerland (ISBN 978-3-940388-48-3). 2009.Shi, C., Jiménez, A. F., & Palomo, A. (2011). New cements for the 21st century: The pursuit of an alternative to Portland cement. Cement and Concrete Research, 41(7), 750-763. doi:10.1016/j.cemconres.2011.03.016Duxson, P., Fernández-Jiménez, A., Provis, J. L., Lukey, G. C., Palomo, A., & van Deventer, J. S. J. (2006). Geopolymer technology: the current state of the art. Journal of Materials Science, 42(9), 2917-2933. doi:10.1007/s10853-006-0637-zFernández-Jiménez, A., Palomo, A., & Criado, M. (2005). Microstructure development of alkali-activated fly ash cement: a descriptive model. Cement and Concrete Research, 35(6), 1204-1209. doi:10.1016/j.cemconres.2004.08.021Hossain, A. B., Shirazi, S. A., Persun, J., & Neithalath, N. (2008). Properties of Concrete Containing Vitreous Calcium Aluminosilicate Pozzolan. Transportation Research Record: Journal of the Transportation Research Board, 2070(1), 32-38. doi:10.3141/2070-05Neithalath, N., Persun, J., & Hossain, A. (2009). Hydration in high-performance cementitious systems containing vitreous calcium aluminosilicate or silica fume. Cement and Concrete Research, 39(6), 473-481. doi:10.1016/j.cemconres.2009.03.006Tashima MM, Soriano L, Borrachero MV, Monzó J, Payá J. Effect of curing time on the microstructure and mechanical strength development of alkali activated nbinders based on vitreous calcium aluminosilicate (VCAS). Bull. Mater. Sci. in press.Hemmings RT, Nelson RD, Graves PL, Cornelius BJ. White pozzolan composition and blended cements containing same. Patent US6776838. 2004.Provis, J. L., Lukey, G. C., & van Deventer, J. S. J. (2005). Do Geopolymers Actually Contain Nanocrystalline Zeolites? A Reexamination of Existing Results. Chemistry of Materials, 17(12), 3075-3085. doi:10.1021/cm050230iCriado, M., Fernández-Jiménez, A., de la Torre, A. G., Aranda, M. A. G., & Palomo, A. (2007). An XRD study of the effect of the SiO2/Na2O ratio on the alkali activation of fly ash. Cement and Concrete Research, 37(5), 671-679. doi:10.1016/j.cemconres.2007.01.013Rees, C. A., Provis, J. L., Lukey, G. C., & van Deventer, J. S. J. (2007). In Situ ATR-FTIR Study of the Early Stages of Fly Ash Geopolymer Gel Formation. Langmuir, 23(17), 9076-9082. doi:10.1021/la701185gLee, W. K. W., & van Deventer, J. S. J. (2003). Use of Infrared Spectroscopy to Study Geopolymerization of Heterogeneous Amorphous Aluminosilicates. Langmuir, 19(21), 8726-8734. doi:10.1021/la026127eGarcía-Lodeiro, I., Fernández-Jiménez, A., Blanco, M. T., & Palomo, A. (2007). FTIR study of the sol–gel synthesis of cementitious gels: C–S–H and N–A–S–H. Journal of Sol-Gel Science and Technology, 45(1), 63-72. doi:10.1007/s10971-007-1643-6Barbosa VFF. Sintese e caracterização de polissialatos (Synthesis and characterization of polysialates) [PhD thesis] (in Portuguese). Instituto Militar de Engenharia. Rio de Janeiro - Brazil. 190 p. 1999.Bernal, S. A., Rodríguez, E. D., Mejía de Gutiérrez, R., Gordillo, M., & Provis, J. L. (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-zBoccaccini, A. R., Bücker, M., Bossert, J., & Marszalek, K. (1997). Glass matrix composites from coal flyash and waste glass. Waste Management, 17(1), 39-45. doi:10.1016/s0956-053x(97)00035-4Kourti, I., Rani, D. A., Deegan, D., Boccaccini, A. R., & Cheeseman, C. R. (2010). Production of geopolymers using glass produced from DC plasma treatment of air pollution control (APC) residues. Journal of Hazardous Materials, 176(1-3), 704-709. doi:10.1016/j.jhazmat.2009.11.089Lampris, C., Lupo, R., & Cheeseman, C. R. (2009). Geopolymerisation of silt generated from construction and demolition waste washing plants. Waste Management, 29(1), 368-373. doi:10.1016/j.wasman.2008.04.007Wu, H.-C., & Sun, P. (2007). New building materials from fly ash-based lightweight inorganic polymer. Construction and Building Materials, 21(1), 211-217. doi:10.1016/j.conbuildmat.2005.06.052Kourti, I., Amutha Rani, D., Boccaccini, A. R., & Cheeseman, C. R. (2011). Geopolymers from DC Plasma–Treated Air Pollution Control Residues, Metakaolin, and Granulated Blast Furnace Slag. Journal of Materials in Civil Engineering, 23(6), 735-740. doi:10.1061/(asce)mt.1943-5533.000017

Geopolymer/PEG Hybrid Materials Synthesis and Investigation of the Polymer Influence on Microstructure and Mechanical Behavior

Geopolymers are aluminosilicate inorganic polymers, obtained from the alkali activation of powders containing SiO2+Al2O3>80wt%, mainly proposed as environmentally friendly building materials. In this work, metakaolin-based geopolymers have been prepared and a water-soluble polymer, polyethylene glycol (PEG), has been added in different percentages to obtain organic-inorganic hybrid geopolymers. The influence of both the polymer amount and aging time on the structure and the mechanical behavior of the materials were investigated. FTIR spectroscopy allowed us to follow the evolution of the aluminosilicate framework during the geopolymerization process. This analysis revealed that PEG leads to a network which is rich in Al-O-Si bonds and forms H-bonds with the inorganic phase. SEM microscope showed that the two phases are interpenetrated on micrometric scales. Traction and bending tests have been carried out on appropriate samples to investigate the mechanical behavior of the obtained hybrids, showing that both PEG content and aging time affect the material behavior