Lowering carbon foot print of Portland cement by class F fly ash substitution in mortar mixture in terms of workability and strength properties

Year 2020, , 34 - 46, 31.03.2020

Asadullah Zakı , Cengiz Atiş

https://doi.org/10.46740/alku.731687

Abstract

In the experimental work, recycling by inclusion of class F fly ash in mortar was investigated in terms of workability and strength of mortar to fabricate an environment friendly construction material. For this aim, class F fly ash were used as cement replacement at 10%, 30%, 50% and 70% ratios in mortar. Water-binder ratios were 0.40, 0.45 and 0.50. A total of 15 different mortar mixtures including control Portland cement and fly ash mortar were produced. Workability of fresh mortar was measured using mini flow testing. Flexural and compressive strength of hardened standard sized samples were measured after completion of their specified curing time at 1d, 3d, 7d 28d, 3m and 6m. Experimental results showed that inclusion of fly ash in mortar improved workability with respect to control Portland cement mortar. Recycling low amount of fly ash in mortar did not show detrimental but beneficial influence on strength properties of mortar. However, employing high amount of fly ash in mortar reduced flexural and compressive strength at early ages, however, the reduction in flexural and compressive strengths were remedied due to pozzolanic reaction of fly ash at longer curing time compared to control Portland cement mortar. It was concluded that current fly ash was a suitable pozzolanic material to be recycled by replacement with Portland cement in mortar to manufacture clean construction material in terms of workability and strength concern.

Keywords

Mortar, Fly ash, Workability, Strength

References

• [1] ASTM - C618–8a, (2009). ASTM - C618–8a, Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete, ASTM International, USA .
• [2] Hemalatha, T., Ramaswamy, T. A., (2017). A review on fly ash characteristics - towards promoting high volume utilization in developing sustainable concrete, Journal of Cleaner Production 147, 546-559.
• [3] Papadakis, V.G., S., Tsimas, S., (2002). Supplementary cementing materials in concrete: Part I: efficiency and design, Cement and Concrete Research, 32, 1525-1532. [4] Papadakis, V.G., Antiohos, S. (2002). Tsimas, Supplementary cementing materials in concrete: Part II: A fundamental estimation of the efficiency factor, Cement and Concrete Research, 32, 1533-1538.
• [5] Rafieizonooz, M., Mirza, J., Salim, M.R., Hussin, M.W., & Khankhaj, E., (2006). Investigation of coal bottom ash and fly ash in concrete as replacement for sand and cement, Construction and Building Materials, 116, 15-24.
• [6] Maslehuddin, M., (1989). Effect of sand replacement on the early-age strength, gain and long-term corrosion-resisting characteristics of fly ash concrete, ACI Mater. J., 86, 58 – 62.
• [7] Yao, Z.T., Ji, X.S., Sarker, P.K., Tang, J.H. Ge, L.Q., Xia, M.S., & Y.Q. Xi, Y.Q., (2015). A comprehensive review on the applications of coal fly ash, Earth Sci Rev, 141, 105-121.
• [8] Siddique, R., (2004). Performance characteristics of high-volume Class F fly ash concrete, Cement and Concrete Research 34, 487– 493.
• [9] Ravina, D., P.K. Mehta, P.K., (1986). Properties of fresh concrete containing large, amounts of fly ash, Cement and Concrete Research, 16, 227–238.
• [10] Chindaprasirt, P., Jaturapitakkul, C., & Sinsiri, T., (2005). Effect of fly ash fineness on compressive strength and pore size of blended cement paste, Cement Concr Compos, 27, 425-428.
• [11] Ali, M.B., Saidur, R., & Hossain, M.S., (2011). A review on emission analysis in cement industries, Renewable Sustainable Energy Rev., 15, 2252-2261.
• [12] Guo, X., H. Shi, H., & Dick, W.A., (2010). Compressive strength and microstructural characteristics of class C fly ash geopolymer, Cement Concr. Compos., 32, 142-147.
• [13] EPA, (2008). EPA, Study on Increasing the Usage of Recovered Mineral Components in Federally Funded Projects Involving Procurement of Cement or Concrete, Environmental Protection Agency.
• [14] Wardhono, A., Law, D.W., & Strano, A., (2015). The Strength of Alkali-activated Slag/fly Ash Mortar Blends at Ambient Temperature, Procedia Engineering, 125, 650-656.
• [15] TS EN 196-1, (2002). Method of Testing Cement, Part 1: Determination of Strength, TSE, , Ankara, Turkey.
• [16] ASTM C230, (2008). Standard Specification for Flow Table for Use in Tests of Hydraulic Cement, ASTM International, 100 Barr Harbour Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
• [17] TS EN 1015-11, (2000). Mortar Testing Method, Part 11: Measurement of Compressive and Flexural Tensile Strength of Mortar, TSE, Ankara, Turkey.
• [18] Ahmaruzzaman, M., (2010). A review on the utilization of fly ash, Prog Energy Combust Sci, 36, 327-363.
• [19] Gopalan, M.K., (1993). Nucleation and pozzolanic factors in strength development of class F fly ash concrete, ACI Mater. J., 90, 117-121.
• [20] Aïtcin, P.C., Flatt, R.J., (2006). Science and Technology of Concrete Admixtures, Woodhead Publishing Series in Civil and Structural Engineering: Number 59, ISBN: 978-0-08-100693-1, Woodhead Publishing, Elsevier.
• [21]Isaia, G.C., Gastaldini, A.L.G., & Moraes, R., (2003). Physical and pozzolanic action of mineral additions on the mechanical strength of high-performance concrete, Cem. Concr. Compos., 25, 69-76.