Document Type : Research Paper


Civil Engineering Dept., University of Technology-Iraq, Alsina’a street, 10066 Baghdad, Iraq.


Geopolymer concrete is an inorganic composite material created by interacting alkaline substances with an aluminosilicate source and aggregate. Precast building units are considered the most prominent uses of geopolymer concrete, and the utilization of recycled steel fibres and rubber from damaged tires that are non-biodegradable to reduce environmental pollution. The results of this investigation show the possibility of using geopolymer concrete with and without the inclusion of crumbed rubber and recycled steel fibers from damaged tires in the production of paving flags with dimensions of 400 × 200 × 50 mm class c according to IQS 1107. Four types of geopolymer concrete flags were prepared, including flag specimens without wastes, flag specimens reinforced with recycled steel fibres waste from damaged car tires with a volume fraction of 0.125%, flag specimens containing 10% crumbed rubber waste aggregate as a partial volumetric replacement to natural coarse aggregate, as well as flag specimens containing two wastes of 10% crumbed rubber as a partial replacement to natural coarse aggregate and 0.125% recycled steel fibres. The experimental tests illustrate that it is possible to reduce the thickness from 50 mm to 35 mm of the paving flags to reduce their weight and cost. In addition, it was discovered that the total flexural energy of paving flags containing recycled steel fibers and rubber aggregate wastes increased by 390% and 271%, respectively, concerning paving flags without wastes. The failure modes changed from brittle to ductile when these wastes were used. 

Graphical Abstract


  • Producing paving flags from modified MK-based GPC and containing different waste materials according to IQS 1107
  • Studying properties of GPC paving flags that contain recycled rubber wastes and/or steel fibers from the damaged tires
  • Rupture load, weight, and total flexural energy are improved for GPC paving flags by including waste materials
  • Achieving sustainability by using GPC  without cement, and they save the environment from damaged tire waste


Main Subjects

  1. N. Soutsos, K. Tang, S.G. Millard, The use of recycled demolition aggregate in precast concrete products – phase III: Concrete pavement flags, Constr. Build. Mater., 36 (2012) 674–680.
  2. Muhammed, D. Varkey, An experimental study on fly ash based Geopolymer pavement block with polypropylene fiber‏, Int. J. Innov. Sci. Eng. Technol., 3 (2016) 548–553.
  3. S. Mohammed, M.S. Liew, W.S. Alaloul, A. Al-Fakih, W. Ibrahim, M. Adamu, Development of rubberized geopolymer interlocking bricks‏, Case Stud. Constr. Mater., 8 (2018) 401–408.
  4. Priya Rachel, Study on geopolymer concrete block, Indian J. Appl. Res., 5 (2015) 66–69.
  5. Niphadkar, Geopolymer Masonry Block: A Substitute Material for Cement Concrete Block, SSRN Electron. J., (2020) 1–6.
  6. Iraqi-specification-No.1107, Precast concrete flags, Cent. Organ. Stand. Qual. Control Iraq, 1987.
  7. F. Ahmed, Properties of Geopolymer Concrete Containing Waste Materials, 2020.
  8. ASTM - C618-22, Standard specification for coal fly ash and raw or calcined natural pozzolan for use in concrete, Am. Soc. Test. Mater. Annu. B. West Conshohocken, PA, USA, (2022).
  9. Dubai CHEM, Sodium Silicate Liquid Supplier,, UAE, Accessed April 2022.
  10. Iraqi-Specification-No. 45, Aggregate from natural sources for concrete and construction, Cent. Organ. Iraq, 2016.
  11. Iraqi-Specification-No.23, Standard sieves, Cent. Organ. Iraq, 1980.
  12. ASTM-C494M-17, Standard specification for chemical admixtures for concrete, Am. Soc. Test. Mater. Annu. B. West Conshohocken, PA, USA, 2017.
  13. DCP, Data Sheet for Flocrete SP33, Saudi Arab., Accessed March 2022.
  14. Sika-Company, Silica fume,, Accessed April 2022.
  15. ASTM-C1240, Standard specification for silica fume used in cementitious mixtures, Am. Soc. Test. Mater. Annu. B. West Conshohocken, PA, USA, 2020.
  16. Al-Noura Factory in Karbala,, Accessed April 2022.
  17. Centonze, M. Leone, M.A. Aiello, Steel fibers from waste tires as reinforcement in concrete: a mechanical characterization, Constr. Build. Mater., 36 (2012) 46–57.
  18. ACI-544, State-of-the-art report on fiber reinforced concrete, Concr. Int., 4 (1982) 9–30.
  19. Xue and M. Cao, Effect of modified rubber particles mixing amount on properties of cement mortar, Adv. Civ. Eng., 5 (2017) 1–6.
  20. Segre, P.J. Monteiro, G. Sposito, Surface characterization of recycled tire rubber to be used in cement paste matrix, J. Colloid Interface Sci., 248 (2002) 521–523.
  21. Siddique, E. Kadri, Properties of high-volume fly ash concrete reinforced with natural fibres, Leonardo J. Sci., 21 (2012) 83–98.
  22. ASTM - C29M-15, Standard test method for bulk density (“unit weight”) and voids in aggregate, Am. Soc. Test. Mater. Annu. B. West Conshohocken, PA, USA, 2015.
  23. ASTM-C127-12, Standard test method for density, relative density (specific gravity), and absorption of coarse aggregate, Am. Soc. Test. Mater. Annu. B. West Conshohocken, PA, USA, 2012.
  24. Al-Shathr, B., Al-Attar, T., Hasan, Z., Optimization of geopolymer concrete based on local Iraqi metakaolin‏, in: 2nd Int. Conf. Build. Constr. Environ. Eng. Beirut, Lebanon, 97–100, 2015.
  25. Hadi, N. Farhan, M. Sheikh, Design of geopolymer concrete with GGBFS at ambient curing condition using Taguchi method, Constr. Build. Mater., 140 (2017) 424–431.
  26. Li, C. Shi, Z. Zhang, H. Wang, Y. Liu, A review on mixture design methods for geopolymer concrete, Compos. Part B Eng., 178 (2019) 1–14.
  27. Tobeia, N. Assi, N. Abbas, Mechanical Properties Prediction of Normal and High Strength Geopolymer Concrete, Eng. Technol. J., 39 (2021) 1781–1788.
  28. I. Khalil, Q.J. Frayyeh, M.F. Ahmed, Characteristics of Eco-friendly Metakaolin Based Geopolymer Concrete Pavement Bricks, Eng. Technol. J., 38 (2020) 1706–1716.
  29. Shamsa, B. Al-Shathr, T. Al-Attar, Performance of Geopolymer Concrete Exposed to Freezing and Thawing Cycles, Eng. Technol. J., 37 (2019) 78–84.
  30. S. Radhi, Z.M.R. Abdul-Rasoul, L.M.R. Mahmmod, Effect of the wire mesh reinforcement on some properties of the precast concrete tiles, AL-Qadisiyah J. Eng. Sci., 11 (2019) 256–269.
  31. Li, T.C. Ling, K. Hung Mo, Functions and impacts of plastic/rubber wastes as eco-friendly aggregate in concrete – a review, Constr. Build. Mater., 240 (2020) 117869.
  32. R. Karimi, M.R.M. Aliha, E. Khedri, A. Mousavi, S.M. Salehi, P.J. Haghighatpour, P. Ebneabbasi, Strength and cracking resistance of concrete containing different percentages and sizes of recycled tire rubber granules, J. Build. Eng., 67 (2023) 106033.
  33. M. Yang, K.H. Min, H.O. Shin, Y.S. Yoon, Effect of steel and synthetic fibers on flexural behavior of high-strength concrete beams reinforced with FRP bars, Compos. Part B Eng., 43 (2012) 1077–1086.
  34. V. Balendran, F.P. Zhou, A. Nadeem, A.Y.T. Leung, Influence of steel fibres on strength and ductility of normal and lightweight high strength concrete, Build. Environ., 37 (2002) 1361–1367.
  35. Ranjbaran, O. Rezayfar, R. Mirzababai, Experimental investigation of steel fiber-reinforced concrete beams under cyclic loading, Int. J. Adv. Struct. Eng., 10 (2018) 49–60.
  36. Bencardino, L. Rizzuti, G. Spadea, R.N. Swamy, Stress–strain behavior of steel fiber-reinforced concrete in compression, J Mater Civ. Eng., 20 (2008) 255–263.
  37. ASTM-C78, Standard test method for flexural strength of concrete (using simple beam with third-point loading), Am. Soc. Test. Mater. Annu. B. West Conshohocken, PA, USA, 2015.
  38. Z. Ismail, E.A. AL-Hashmi, Use of waste plastic in concrete mixture as aggregate replacement, Waste Manag., 28 (2008) 2041–2047.
  39. Guo, P. Zhang, Y. Tian, B. Wang, W. Ma, Influence of the amount of steel fibers on fracture energy and drying shrinkage of HPFRCC, Adv. Mater. Sci. Eng., 2020 (2020) 1–15.