Effect of silica fume on the fresh and hardened properties of fly ash-based self-compacting geopolymer concrete

Abstract

The effect of silica fume on the fresh and hardened properties of fly ash-based self-compacting geopolymer concrete (SCGC) was investigated in this paper. The work focused on the concrete mixes with a fixed water-to-geopolymer solid (W/Gs) ratio of 0.33 by mass and a constant total binder content of 400 kg/m³. The mass fractions of silica fume that replaced fly ash in this research were 0wt%, 5wt%, 10wt%, and 15wt%. The workability-related fresh properties of SCGC were assessed through slump flow, V-funnel, and L-box test methods. Hardened concrete tests were limited to compressive, splitting tensile and flexural strengths, all of which were measured at the age of 1, 7, and 28 d after 48-h oven curing. The results indicate that the addition of silica fume as a partial replacement of fly ash results in the loss of workability; nevertheless, the mechanical properties of hardened SCGC are significantly improved by incorporating silica fume, especially up to 10wt%. Applying this percentage of silica fume results in 4.3% reduction in the slump flow; however, it increases the compressive strength by 6.9%, tensile strength by 12.8% and flexural strength by 11.5%.

Keywords

geopolymer concrete / silica fume / fresh properties / compressive strength / tensile strength / flexural strength

References

[1] Rangan B.V. Fly Ash-based Geopolymer Concrete, 2010, Perth, Curtin University of Technology, 68.

[2] Davidovits J. Geopolymer cements to minimise carbondioxide greenhouse-warming. Ceram. Trans., 1993, 37, 165.

[3] Davidovits J. Geopolymer Chemistry and Applications, 2008 2nd Ed. Saint-Quentin, Institut Géopolym`ere, 276.

[4] Hardjito D., Wallah S.E., Sumajouw D.M.J., Rangan B.V. Factors influencing the compressive strength of fly ash-based geopolymer concrete. Civ. Eng. Dimens., 2004, 6(2): 88.

[5] Boukendakdji O., Kenai S., Kadri E.H., Rouis F. Effect of slag on the rheology of fresh self-compacted concrete. Constr. Build. Mater., 2009, 23(7): 2593.

[6] Druta C. Tensile Strength and Bonding Characteristics of Self-Compacting Concrete, 2003, Bucharest, Polytechnic University of Bucharest, 5.

[7] European Federation of Specialist Construction ChemicalsConcrete Systems. Specification and Guidelines for Self-Compacting Concrete, 2002, Surrey, EFNARC Association House, 4.

[8] Liu M. Self-compacting concrete with different levels of pulverized fuel ash. Constr. Build. Mater., 2010, 24(7): 1245.

[9] Okamura H., Ouchi M. Self-compacting concrete. J. Adv. Concr. Technol., 2003, 1(1): 5.

[10] Nanthagopalan P., Santhanam M. A new empirical test method for the optimisation of viscosity modifying agent dosage in self-compacting concrete. Mater. Struct., 2010, 43(1–2): 203.

[11] Koehler E.P. Aggregates in Self-Consolidating Concrete, 2007, Austin, The University of Texas at Austin, 38.

[12] Dehwah H.A.F. Mechanical properties of self-compacting concrete incorporating quarry dust powder, silica fume or fly ash. Constr. Build. Mater., 2012, 26(1): 547.

[13] K.C. Biswal1 and S.C. Sadangi, Effect of superplasticizer and silica fume on properties of concrete, [in] Proceedings of International Confence on Advances in Civil Engineering, Trivandrum, 2010, p. 94.

[14] Caldarone M.A. High-Strength Concrete: a Practical Guide, 2008, New York, Taylor & Francis, 43.

[15] Neville A.M. Properties of Concrete, 1995 4th Ed New York, Wiley Publishers, 844.

[16] Meyer C. The greening of the concrete industry. Cem. Concr. Compos., 2009, 31(8): 601.

[17] Barbhuiya S.A., Gbagbo J.K., Russell M.I., Basheer P.A.M. Properties of fly ash concrete modified with hydrated lime and silica fume. Constr. Build. Mater., 2009, 23(10): 3233.

[18] Memon F.A., Nuruddin F., Shafiq N. Compressive strength and workability characteristics of low-calcium fly ash-based self-compacting geopolymer concrete. Int. J. Civ. Environ. Eng., 2011, 3(2): 72.

[19] Memon F.A., Nuruddin F., Demie S., Shafiq N. Effect of curing conditions on strength of fly ash-based selfcompacting geopolymer concrete. Int. J. Civ. Environ. Eng., 2011, 3(3): 183.

[20] ASTM C618. Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use as a Mineral Admixture in Concrete, 2004, West Conshohocken, American Society for Testing and Materials, 2.

[21] SS EN 450-1. Fly Ash for Concrete: Part 1. Definition, Specifications and Conformity Criteria, 2012, Stockholm, Swedish Standards Institute, 40.

[22] BS EN 13263-1. Silica Fume for Concrete: Part 1. Definitions, Requirements and Conformity Criteria, 2005, London, British Standards Institute, 10.

[23] ASTM C136. Standard Test Method for Sieve Analysis of Fine Aggregates, 2004, Philadelphia, Annual Book of ASTM Standards, American Society for Testing and Materials, 84.

[24] BS 882: 1992. Specification for Aggregates from Natural Sources for Concrete, 1992, London, British Standards Institute, 14.

[25] ASTM C33. Specifications for Concrete Aggregates, 2004, Philadelphia, Annual Book of ASTM Standards, American Society for Testing and Materials, 10.

[26] European Federation of Specialist Construction ChemicalsConcrete Systems. The European Guidelines for Self-Compacting Concrete: Specification, Production and Use, 2005, Surrey, The Self-Compacting Concrete European Project Group, 47.

[27] BS EN 12390-3. Testing Hardened Concrete: Part 3. Compressive Strength of Test Specimens, 2002, London, British Standards Institute, 5.

[28] Mindess S., Young J.F., Darwin D. Concrete, 2002, New Jersey, PrenticeHall Inc., 315.

[29] SS EN 12390-6. Testing Hardened Concrete: Part 6. Tensile Splitting Strength of Test Specimens, 2004, Stockholm, Swedish Standards Institute, 6.

[30] ASTM C496/C496M-11. Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens, 2004, Philadelphia, Annual Book of ASTM Standards, American Society for Testing and Materials, 287.

[31] BS EN 12390-5. Testing Hardened Concrete: Part 5. Flexural Strength of Test Specimens, 2009, London, British Standards Institute, 5.

[32] ASTM C78/C78M-10. Standard Test Method for Flexural Strength of Concrete, 2004, Philadelphia, Annual Book of ASTM Standards, American Society for Testing and Materials, 39.

[33] Andri K. Alkali-activation of Fly Ash/MIRHA Blend in Geopolymer Concrete for In-situ Application, 2012, Kuala Lumpur, Universiti Teknologi PETRONAS, 148.

[34] Bhanja S., Sengupta B. Influence of silica fume on the tensile strength of concrete. Cem. Concr. Res., 2005, 35(4): 743.

[35] Newman J., Choo B.S. Advanced Concrete Technology: Constituent Materials, 2003, Jordan Hill, Burlington, Butterworth-Heinemann, 48.

[36] Yang Z.X., Ha N.R., Jang M.S., Hwang K.H., Lee J.K. The effect of SiO₂ on the performance of inorganic sludgebased structural concretes. J. Ceram. Process. Res., 2009, 10(3): 266.

[37] Dutta D., Thokchom S., Ghosh P., Ghosh S. Effect of silica fume additions on porosity of fly ash geopolymers. J. Eng. Appl. Sci., 2010, 5(10): 74.