Title:
Effect of Recycled Aggregate and Steel Fibers on the Mechanical Properties of Alkali-Activated Slag/Fly Ash Blended Concrete
Author(s):
Jamal Medljy, Hilal El-Hassan, and Tamer El-Maaddawy
Publication:
Symposium Paper
Volume:
349
Issue:
Appears on pages(s):
210-223
Keywords:
alkali-activated concrete, compressive strength, recycled aggregates, regression models, steel fibers
DOI:
10.14359/51732748
Date:
4/22/2021
Abstract:
This paper focuses on developing ambient-cured alkali-activated concrete incorporating recycled concrete aggregates (RA). The binder was either slag or a blend of slag and fly ash (3:1, by mass). Hook-ended steel fibers were added, in 2% volumetric fraction, to improve the properties of concrete made with RA. The alkaline activator solution was a blend of sodium silicate and sodium hydroxide. Concrete mixtures were proportioned to achieve three target compressive strengths, namely 30, 45, and 60 MPa. The performance of concrete mixtures was assessed based on 1, 7, and 28-day compressive strengths. Experimental results showed that full replacement of natural aggregates
by RA caused up to 28% reduction in compressive strength of plain alkali-activated slag concretes, with greater reductions being reported in mixtures with higher target strength and tested at 28 days. The incorporation of 2% steel fibers enhanced the strength and caused limited strength reductions of up to 7%. Compared to alkali-activated slag RA concretes, mixtures with 25% fly ash replacement exhibited lower strengths at 1 and 7 days, but their 28-day strength was superior. Analytical multi-linear regression models were developed to identify statistical significance of concrete components and examine their impact on the compressive strength.
Related References:
1. US Geological Survey. Minerals commodity summary - cement. 2016 cited 2016 October 6..
2. Afkhami, B., Akbarian, B., Beheshti A, N., Kakaee, A.H., and Shabani, B., 2015, "Energy consumption assessment in a cement production plant", Sustainable Energy Technologies and Assessments, 10, 84-89.
3. Thakur, R.N. and Wu, Z., Development of High-Performance Blended Cements, in College of Engineering and Applied Science. The University of Wisconsin: USA (2000).
4. Davidovits, J., 1994, "High-Alkali Cements for 21st Century Concretes", Special Publication, 144.
5. Benhelal, E., Zahedi, G., Shamsaei, E., and Bahadori, A., 2013, "Global strategies and potentials to curb CO2 emissions in cement industry", Journal of Cleaner Production, 51, 142-161.
6. Herzog, H.J., Eliasson, B., and Kaarstad, O., 2000, "Capturing greenhouse gases", Scientific American, 282, 72-79.
7. Earth System Research Laboratory, 2013, "Trends in Atmospheric Carbon Dioxide".
8. El-Hassan, H. and Ismail, N., 2018, "Effect of process parameters on the performance of fly ash/GGBS blended geopolymer composites", Journal of Sustainable Cement-Based Materials, 7(2), 122-140.
9. Ismail, N. and El-Hassan, H., 2018, "Development and Characterization of Fly Ash/Slag-Blended Geopolymer Mortar and Lightweight Concrete", Journal of Materials in Civil Engineering, 30(4).
10. Aydın, S. and Baradan, B., 2014, "Effect of activator type and content on properties of alkali-activated slag mortars", Composites Part B: Engineering, 57, 166-172.
11. El-Hassan, H., Shehab, E., and Alsallamin, A., 2018, "Influence of Different Curing Regimes on the Performance and Microstructure of Alkali-Activated Slag Concrete", Journal of Materials in Civil Engineering, 30(9).
12. Collins, F. and Sanjayan, J.G., 2001, "Microcracking and strength development of alkali activated slag concrete", Cement and Concrete Composites 23(4), 345-352.
13. Shi, C., 2003, "Corrosion resistance of alkali-activated slag cement", Advances in Cement Research, 15(2), 77-81.
14. Karahan, O. and Yakupoğlu, A., 2011, "Resistance of alkali-activated slag mortar to abrasion and fire", Advances in Cement Research, 23(6), 289-297.
15. van Deventer, J.S.J., San Nicolas, R., Ismail, I., Bernal, S.A., Brice, D.G., and Provis, J.L., 2015, "Microstructure and durability of alkali-activated materials as key parameters for standardization", Journal of Sustainable Cement-Based Materials, 4(2), 116-128.
16. Bernal, S.A., Rodríguez, E.D., Mejía de Gutiérrez, R., and Provis, J.L., 2012, "Performance of alkali-activated slag mortars exposed to acids", Journal of Sustainable Cement-Based Materials, 1(3), 138-151.
17. Zhang, W., Yao, X., Yang, T., and Zhang, Z., 2018, "The degradation mechanisms of alkali-activated fly ash/slag blend cements exposed to sulphuric acid", Construction and Building Materials, 186, 1177-1187.
18. Rodrigue, A., Duchesne, J., Fournier, B., and Bissonnette, B., 2018, "Influence of added water and fly ash content on the characteristics, properties and early-age cracking sensitivity of alkali-activated slag/fly ash concrete cured at ambient temperature", Construction and Building Materials, 171, 929-941.
19. Wardhono, A., Law, D.W., and Strano, A., 2015, "The Strength of Alkali-activated Slag/fly Ash Mortar Blends at Ambient Temperature", Procedia Engineering, 125, 650-656.
20. Zhang, J., Shi, C., Li, Y., Pan, X., Poon, C.S., and Xie, Z., 2015, "Performance Enhancement of Recycled Concrete Aggregates through Carbonation", Journal of Materials in Civil Engineering, 27(11).
21. Kong, D., Lei, T., Ma, C., and Jiang, J., 2010, "Effect and mechanism of surface-coating pozzolanic materials around aggregate on properties and ITZ microstructure of recycled aggregate concrete", Construction and Building Materials, 24(5), 701-708.
22. Poon, C. and Chan, D., 2007, "The use of recycled aggregate in concrete in Hong Kong", Resources Conservation Recycling, 50(3), 293-305.
23. Parthiban, K. and Saravana Raja Mohan, K., 2017, "Influence of recycled concrete aggregates on the engineering and durability properties of alkali activated slag concrete", Construction and Building Materials, 133(Supplement C), 65-72.
24. Kathirvel, P. and Kaliyaperumal, S.R.M., 2016, "Influence of recycled concrete aggregates on the flexural properties of reinforced alkali activated slag concrete", Construction and Building Materials, 102(Part 1), 51-58.
25. ASTM, ASTM C168-15: Standard specification for coal fly ash and raw or calcined natural pozzolan for use in concrete. 2015, American Society for Testing and Materials International: West Conshohoken, USA.
26. ASTM, Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates, in C136. ASTM International: USA (2014).
27. ASTM, Standard Specification for Concrete Aggregates, in C33. ASTM International: West Conshohocken, PA (2016).
28. ASTM, Standard Test Method for Soundness of Aggregates by Use of Sodium Sulfate or Magnesium Sulfate, in C88. ASTM International: West Conshohocken, PA (2013).
29. ACI Committee E-701, Aggregates for Concrete. 2016, American Concrete Institute: Farmington Hills, Michigan.
30. Hossain, M.S., Lane, D.S., and Schmidt, B.N., Use of the Micro-Deval Test for Assessing the Durability of Virginia Aggregates, V.T.R. Council, Editor. 2007, Virginia Transportation Research Council: Charlottesville, Virginia.
31. ASTM, Standard Test Method for Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine, in C131. ASTM International: West Conshohocken, PA (2014).
32. Palacios, M. and Puertas, F., 2005, "Effect of superplasticizer and shrinkage-reducing admixtures on alkaliactivated slag pastes and mortars", Cement and Concrete Research 35(7), 1358-1367.
33. Yoo, D.-Y. and Kim, S., 2019, "Comparative pullout behavior of half-hooked and commercial steel fibers embedded in UHPC under static and impact loads", Cement and Concrete Composites, 97, 89-106.
34. Han, J., Zhao, M., Chen, J., and Lan, X., 2019, "Effects of steel fiber length and coarse aggregate maximum size on mechanical properties of steel fiber reinforced concrete", Construction and Building Materials, 209, 577-591.
35. El-Hassan, H. and Elkholy, S., 2019, "Performance Evaluation and Microstructure Characterization of Steel Fiber-Reinforced Alkali-Activated Slag Concrete Incorporating Fly Ash", Journal of Materials in Civil Engineering, 31(10), 04019223.
36. Ismail, I., Bernal, S.A., Provis, J.L., San Nicolas, R., Hamdan, S., and van Deventer, J.S.J., 2014, "Modification of phase evolution in alkali-activated blast furnace slag by the incorporation of fly ash", Cement and Concrete Composites, 45, 125-135.
37. ASTM, Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens, in C39. ASTM: West Conshohocken, PA (2015).