Title:
Thermal Behaviour of High Volumn Fly Ash Concrete and Its Teperature Simulation
Author(s):
Peter G. Gaunt, Mathew K.R. Versfeld, André Ferreira and Stephen O. Ekolu
Publication:
Symposium Paper
Volume:
320
Issue:
Appears on pages(s):
47.1-47.16
Keywords:
compressive strength, ConcreteWorks simulation, durability, heat of hydration, high volume fly ash concrete, temperature
DOI:
10.14359/51701085
Date:
8/1/2017
Abstract:
In this paper, it is shown that Class F fly ash can be effectively used in high volumes as a supplementary cementitious material. High Volume Fly Ash (HVFA) use is of interest in promoting the development and application of green materials. In South Africa, there is little or no literature on high volume incorporation of locally available fly ash in concrete. In this investigation, six different concrete mixtures with water/cementitious ratios of 0.3 and 0.45, were used. The mixtures consisted of 0, 30, 50 and 70% fly ash. Tests carried out were workability, compressive strength and heat of hydration. Large 300 mm cubes were used to study hydration heat development in fresh concrete. As expected, concrete strength decreased as fly ash content increased owing to the slower rate of strength development in fly ash mixtures. It was found that heat of hydration generated in HVFA mixtures gave lower peak temperatures compared to mixtures without fly ash, producing reductions of 27% to 43.5% in peak temperatures for mixtures containing 50% and 70% fly ash respectively. Temperature simulation using ConcreteWorks gave predictions correctly depicting the measured temperature profiles but with slight under-estimation of peak temperatures.
Related References:
1. Ravina, D., Mehta P., Properties of fresh concrete containing large amounts of fly ash, Cement and ConcreteResearch, 16, 1986, 227-238.
2. Bilodeau, A., Malhotra, V., High volume fly ash system: concrete solution for sustainable development, ACIMaterials Journal, 97 (1), Jan –Feb 2000.
3. Malhotra V.M, “Chapter 12 – High Volume Fly Ash And Slag Concrete”, in Concrete AdmixturesHandbook (Second Edition), Properties, Science, and Technology, William Andrew Publishers, 1996, 800-838. doi: 10.1016/B978-081551373-5.50016-7
4. Malhotra V.M, High-performance high-volume fly ash concrete, Concrete International, 24 (7), 2002, 1-5
5. Fulton’s, “Fulton’s Concrete Technology”, 9th Edition, Cement and Concrete Institute (C&CI), 2001,Midrand, South Africa, 2009, 439p.
6. Reiner, M. and Rens, K, High-volume fly ash concrete: analysis and application, Practice Periodical onStructural Design and Construction, 2006, 11 (1), 58-64.
7. Hasheela P.F. and Ekolu S.O, Effect of fly ash and slag on the cost of concrete, Proceedings of the NationalSymposium on Concrete for a Sustainable Environment, Concrete Society of Southern Africa, held on 3-4thAugust 2010, Kempton Park, Johannesburg, Gauteng, 50-56.
8. Atis, C, High-volume fly Ash with high strength and low drying shrinkage, Journal of Materials in CivilEngineering,
Online.. 15, 2003, 153-156. http://0-ascelibrary.org.ujlink.uj.ac.za
9. Ekolu S.O, “Role of Heat Curing in Concrete Durability”, PhD Thesis, Department of Civil Engineering,University of Toronto, Canada, 2004, 217p.
10. Ekolu S.O, Heat curing practice in concrete precasting technology - problems and future directions,Concrete Beton, Journal of the Concrete Society of Southern Africa, December 2006, 114: 5-10.
11. Ekolu S.O, Thomas M.D.A and Hooton R.D, Pessimum effect of externally applied chlorides on expansiondue to DEF - proposed mechanism, Cement and Concrete Research, 36, 2006, 688-696.
12. Kosmatka, S. H, "Chapter 3 - Fly Ash, Slag, Silica Fume" in Design and Control of Concrete Mixtures 15E,Portland Cement Association, 2011, 57-72.
13. Afrisam, “Your guide to used of Rapid Hard Cement”, AfriSam, PO Box 6367, Weltevredenpark, 1715,South Africa.
14. Heyns M.W and Hassan M.M, South African Class F fly ash for roads: physical and chemical analysis,www.sabinet.co.za/sa_epublication_article/interim_v12_n3_a4
15. ASTM C143 /C143M-15a, Standard test method for slump of hydraulic-cement concrete, ASTMInternational, West Conshohocken, PA, 2015, www.astm.org
16. SANS 5862-1, Concrete testing – consistence of freshly mixed concrete (slump test), 2006, South AfricanBureau of Standards, Private Bag X191 Pretoria 000, Gauteng.
17. SANS 5863, Concrete testing – compressive strength of hardened concrete, 2006, South African Bureau ofStandards, Private Bag X191 Pretoria 000, Gauteng.
18. Folliard K., Schindler A., Juenger M., Rung M. and Ridling K.. “Concrete Works”, Version 2.0 UserManual. Texas: Concrete Durability Centre, 2005, www.texasconcreteworks.com
19. PCA, “Portland cement, concrete and heat of hydration”, Concrete Technology Today, Portland CementAssociation (PCA), 5420 Old Orchard Road, Skokie, Illinois 60077-1083, 18 (2), July 1997,www.portcement.org