Authors: Yurdakul, E; Jackson, N; Rieder, KA
Editors: Wesseloo, J
Conference: Eighth International Conference on Deep and High Stress Mining, 28-30 March, Perth
Published: Australian Centre for Geomechanics, Proceedings of the Eighth International Conference on Deep and High Stress Mining, pp.723-731, Perth
This paper presents the results of laboratory and field experiments conducted for a major ground support operation to assess the performance of wet-mix shotcrete incorporating various chemical admixtures. The project had an alkali-silica reaction (ASR) risk due to the aggregates available in the region being reactive. Therefore, a customised mix design was prepared and specialty chemical admixtures formulated with the latest available technologies were selected to mitigate the ASR while meeting the project specifications. The performance of the proposed system, which contained 25% fly ash and 0.8% of pozzolanic-based rheology control agent, was compared with the reference mix containing 8% silica fume as well as the target performance limits of the project. Test results showed that, when compared to the reference mix, the proposed system improved the shotcrete performance by reducing the ASR potential, increasing early-age strength, enhancing sprayability by increasing the stickiness and cohesiveness, and meeting later-age strength, toughness, and durability requirements.
Keywords: fly ash, wet-mix shotcrete, ground support
Keywords: fly ash, wet-mix shotcrete, ground support
Yurdakul, E, Jackson, N & Rieder, KA 2017, 'Role of chemical admixtures in improving wet-mix shotcrete performance for ground support', in J Wesseloo (ed.), Proceedings of the Eighth International Conference on Deep and High Stress Mining
, Australian Centre for Geomechanics, Perth, pp. 723-731.
ASTM International 2013, ASTM C1567 Standard test method for determining the potential alkali-silica reactivity of combinations of cementitious materials and aggregate (accelerated mortar-bar method), ASTM International, West Conshohocken, Pennsylvania.
ASTM International 2012, C1609/C1609M Standard test method for flexural performance of fiber-reinforced concrete (using beam with thirdpoint loading), ASTM International, West Conshohocken, Pennsylvania.
Babu, KG & Rao, GSN 1994, ‘Early strength behaviour of fly ash concretes’, Cement and Concrete Research, vol. 24, no. 2, pp. 277–284.
Beaupré, D 1994, ‘Rheology of high performance shotcrete’, PhD thesis, University of British Columbia, pp. 250.
Bergna, HE & Roberts, WO 2006, Colloidal silica fundamentals and applications, Taylor and Francis Group, LLC, Boca Raton.
Chiu, YC & Olek, J 2014, ‘Using modified mortar-bar test method to access the effects of deicers on expansion of mortars with and without reactive aggregates’, 4th International Conference on the Durability of Concrete Structures, West Lafayette, Indiana.
Degirmenci, N, Yilmaz, A & Cakir, A 2011, ‘Utilization of waste glass as sand replacement in cement mortar’, Indian Journal of Engineering & Materials Sciences, vol. 18, pp. 303–308.
Detwiler, R 1997, ‘The role of fly ash composition in reducing alkali-silica reaction’, PCA R&D serial no. 2092, Portland Cement Association.
Garcia-Diaz, E, Riche, J, Bulteel, D & Vernet, C 2006, ‘Mechanism of damage for the alkali-silica reaction’, Cement and Concrete Research, vol. 36, pp. 395–400.
Glasser, DLS & Kataoka, N 1981, ‘The chemistry of alkali-aggregate reaction’, Cement and Concrete Research, vol. 11, no. 1, pp. 1–9.
Jolin, M & Beaupré, D 2003, ‘Understanding wet-mix shotcrete: mix design, specifications, and placement’, Shotcrete Magazine, no. Summer, pp. 6–12.
Lane, RO & Best, JF 1982, ‘Properties and use of fly ash in Portland cement concrete’, Concrete International, vol. 4, no. 7, pp. 81–92.
Malvar, LJ & Lenke, LR 2005, ‘Minimum fly ash cement replacement to mitigate alkali silica reaction’, 2005 World of Coal Ash (WOCA), Lexington, Kentucky.
Morgan, DR, Mindess, S & Chen, L 1995, ‘Testing and specifying toughness for fibre reinforced concrete and shotcrete’, in N Banthia & S Mindess (eds), Proceedings of the 2nd University-Industry Workshop on Fiber Reinforced Concrete and Other Advanced Composites, Toronto, pp. 29–50.
Ovstaas, G, Heere, R, Horth, R & Yurdakul, E 2015, ‘Evaluation of the use of colloidal silica as a silica fume replacement in wet mix shotcrete’, in Proceedings of the 5th International Conference on Construction Materials: Performance, Innovations and Structural Implications, Whistler.
Poyet, S, Sellier, A, Capra, B, Foray, G, Torrenti, JM, Cognon, H & Bourdarot, E 2007, ‘Chemical modelling of alkali silica reaction: Influence of the reactive aggregate size distribution’, Materials and Structures, vol. 40, no. 2, pp. 229–239.
Shafaatian, SMH, Akhavan, A, Maraghechi, H & Rajabipour, F 2013, ‘How does fly ash mitigate alkali-silica reaction (ASR) in accelerated mortar bar test (ASTM C1567)?’, Cement & Concrete Composites, vol. 37, pp. 143–153.
Shehata, MH & Thomas, MDA 2000, ‘The effect of fly ash composition on the expansion of concrete due to alkali-silica reaction’, Cement and Concrete Research, vol. 30, pp. 1063–1072.
Wild, S, Sabir, BB & Khatib, JM 1995, ‘Factors influencing strength development of concrete containing silica fume’, Cement and Concrete Research, vol. 25, no. 7, pp. 1567–1580.
Yurdakul, E & Rieder, KA 2015, ‘Effect of pozzolanic based rheology control agent as a replacement for silica fume on wet-mix shotcrete performance’, Shotcrete Magazine, no. Spring, pp. 26–31.