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

Effect of curing time on the microstructure and mechanical strength development of alkali activated binders based on vitreous calcium aluminosilicate (VCAS)

The aim of this paper is to study the influence of curing time on the microstructure and mechanical strength development of alkali activated binders based on vitreous calcium aluminosilicate (VCAS). Mechanical strength of alkali activated mortars cured at 65 °C was assessed for different curing times (4¿168 h) using 10 molal NaOH solution as alkaline activator. Compressive strength values around 77 MPa after three days of curing at 65 °C were obtained. 1·68 MPa/h compressive strength gain rate was observed in the first 12 h, decreasing to 0·95 MPa/h for the period of 12¿72 h. The progress of geopolymeric reaction was monitored by means of TGA and, electrical conductivity and pH measurements in an aqueous suspension. Significant decrease in pH and electrical conductivity were observed in the 4¿72 h period, demonstrating the geopolymerization process. Furthermore, SEM images showed an important amount of (N, C)ASH gel and low porosity of the developed matrix.To the Ministerio de Ciencia e Innovacion (MICINN) of the Spanish Government (BIA2011-26947) and also to FEDER for funding and to Vitrominerals company for supplying VCAS samples.Mitsuuchi Tashima, M.; Soriano Martínez, L.; Borrachero Rosado, MV.; Monzó Balbuena, JM.; Paya Bernabeu, JJ. (2013). Effect of curing time on the microstructure and mechanical strength development of alkali activated binders based on vitreous calcium aluminosilicate (VCAS). Bulletin of Materials Science. 36:245-249. https://doi.org/10.1007/s12034-013-0466-zS24524936Bernal S A, Gutiérrez R M, Pedraza A L, Provis J L, Rodriguez E D and Delvasto S 2011 Cem. Concr. Res. 41 1Criado M, Fernández-Jiménez A, Sobrados I, Palomo A and Sanz J 2011 J. Eur. Ceram. Soc. avaiable onlineDavidovits J 2008 Geopolymer chemistry and applications Institute Geopolymere, Saint-Quentin, FranceDuxson P, Fernández-Jiménez A, Provis J L, Lukey G C, Palomo A and van Deventer J S J 2007 J. Mater. Sci. 47 2917Fernández-Jiménez A, Palomo A and Criado M 2005 Cem. Concr. Res. 35 1204Hossain A B, Shrazi S A, Persun J and Neithalath N 2008 J. Transp. Res. Board 2070 32Komnitsas K and Zaharaki D 2007 Miner. Eng. 20 1261Lampris C, Lupo R and Cheeseman C R 2009 Waste Manage. 29 368Lin T, Jia D, Wang M, He P and Liang D 2009 Bull. Mater. Sci. 32 77Lloyd R R, Provis J L and van Deventer J S J 2009 J. Mater. Sci. 44 608Marín-López C, Reyes Araiza J L, Manzano-Ramírez A, Rubio Avalos J C, Perez-Bueno J J, Muñiz-Villareal M S, Ventura-Ramos E and Vorobiev Y 2009 Inorg. Mater. 45 1429Najafi Kani E, Allahverdi A and Provis J L 2012 Cem. Concr. Comp. 34 25Neithalath N, Persun J and Hossain A 2009 Cem. Concr. Res. 39 473Pacheco-Torgal F, Castro-Gomes J and Jalali S 2008a Constr. Build. Mater. 22 1315Pacheco-Torgal F, Castro-Gomex J and Jalali S 2008b Constr. Build. Mater. 22 1201Pacheco-Torgal F, Castro-Gomex J and Jalali S 2008c Constr. Build. Mater. 22 2212Payá J, Borrachero M V, Monzó J, Soriano L and Tashima M M 2012 Mater. Lett. 74 223Puertas F, Martínez-Ramírez S, Alonso S and Vázquez T 2000 Cem. Concr. Res. 30 1625Puertas F, Barba A, Gazulla M F, Gómez M P, Palacios M and Martínez-Ramírez S 2006 Mater. Construc. 56 73Reig L, Tashima M M, Borrachero M V, Monzó J and Payá J 2010 II Simposio aprovechamiento de residuos agro-industriales como fuente sostenible de materiales de construcción p. 83Rodriguez E D, Bernal S A, Provis J, Payá J, Monzó J and Borrachero M V 2012 Cem. Concr. Comp. (submitted)Tashima M M, Borrachero M V, Monzó J, Soriano L and Payá J 2009 COMATCOMP09 p.421Tashima M M, Akasaki J L, Castaldelli V N, Soriano L, Monzó J, Payá J and Borrachero M V 2012 Mater. Lett. 80 50Xu H and van Deventer J S J 2000 Int. J. Miner. Process. 59 247Yao X, Zhang Z, Zhu H and Chen Y 2009 Thermochim. Acta 493 49Zivica V 2004 Bull. Mater. Sci. 27 179Zivica V, Balkovic S and Drabik M 2011 Constr. Build. Mater. 25 220

From analytical methods to numerical simulations: A process engineering toolbox for 3D concrete printing

This paper compiles selected predictive analytical and numerical tools which can be used to model and understand the mechanisms of importance at different stages during and immediately after extrusion-based 3D printing of cementitious materials. The proposed toolbox covers different aspects of the process including mixing, material transportation, layer deposition, mechanical behavior of the fresh printed structure, and its early curing. Specifically, the paper provides basic analytical methods that should be helpful for an initial, first-order analysis of a given printing process. These methods deliver, in turn, a first estimation of some material requirements and process parameters. Limitations of these analytical methods are also discussed. Furthermore, the paper presents a review of advanced numerical tools that can be used to simulate the steps in the printing process accurately. It is shown that these tools can serve to describe complex behaviors, help in designing process parameters, or optimizing the rheological response, even though further developments are still needed to capture fully the attendant physical mechanisms

Investigation on the functional and mechanical performance of differentially compacted pervious concrete for road pavements

Pervious concrete aims at being a sustainable and eco-efficient paving material. A lot of studies have indeed been conducted on pervious concrete pavements (PCP) during the last decade but technical standards and rigorous construction specifications are still missing. The present study tested several laboratory-made pervious concrete specimens to define the proper compaction energy able for achieving specific design requirements in terms of porosity (void content) and bulk density; this to therefore guarantee adequate mechanical and functional performances. Different mixes, prepared by combining several water/cement ratios, were compacted using diverse energies and afterwards tested evaluating the void content, the bulk density, the indirect tensile strength, the compressive strength, the elastic modulus, and the permeability coefficient. Outcomes identified the optimal ranges of void contents and bulk densities for each mixture complying to specific permeability and mechanical requirements such as for allowing a wider adoption of PCP on roadways, even if subjected to mid/high traffic levels