Effect of Crushing Process Parameters on Quality of Fly Ash Aggregates Produced After Crushing High Strength Fly Ash Blocks: A Laboratory Investigation

Document Type : Original Article


Department of Civil Engineering, S. V. National Institute of Technology, Surat, Gujarat, India


The demand for aggregates for civil engineering construction is high in the market. The broad adoption of fly ash for producing fly ash aggregate is the best sustainable solution to fulfill aggregate demand and utilization of unused fly ash. Crushing is an essential step for producing angular-shaped aggregate. In this paper, an experimental study using a laboratory-scaled impact crusher was carried out to investigate the effect of crushing process parameters (feed block size, crusher speed and outlet sieve size) on the quality (particle size distribution, flakiness-elongation index and mechanical properties) of angular-shaped fly ash aggregates produced after crushing high-strength fly ash blocks. Particle size distribution and flakiness-elongation index were found to be changed with crushing parameters. Higher crushing speed resulted in small-size fly ash aggregates. Better particle size distribution of crushed fly ash aggregate was produced using a 60 mm outlet sieve compared to a 30 mm one. Well-graded fly ash aggregates with good particle shape (less flaky and less elongated) for the subbase layer of the road were obtained after crushing fly ash blocks of one-third feed size in a laboratory-scaled impact crusher at a crushing speed of 527 rpm and an outlet sieve of 60 mm. Mechanical properties (impact, crushing and abrasion values) of the fly ash aggregate were not much affected by crushing process parameters. The findings of this study will help in optimizing the crushing operation of the industrial impact crusher to produce high-quality angular-shaped fly ash aggregate on a large scale.

Graphical Abstract

Effect of Crushing Process Parameters on Quality of Fly Ash Aggregates Produced After Crushing High Strength Fly Ash Blocks: A Laboratory Investigation


  1. Bakare M, Pai R, Patel S, Shahu J. Environmental sustainability by bulk utilization of fly ash and GBFS as road subbase materials. Journal of Hazardous, Toxic, and Radioactive Waste. 2019;23(4):04019011. https://doi.org/10.1061/(asce)hz.2153-5515.00004502
  2. Turkane S, Chouksey S. Partial replacement of conventional material with stabilized soil in flexible pavement design. International Journal of Engineering, Transactions B: Applications. 2022;35(5):908-16. https://doi.org/10.5829/ije.2022.35.05b.07
  3. Patel S, Shahu J. Comparative study of slags stabilized with fly ash and dolime for utilization in base course. Journal of Materials in Civil Engineering. 2017;29(10):04017168. https://doi.org/10.1061/(asce)mt.1943-5533.0002017
  4. Widodo S, Alfirahma R, Prawiranegara A, Amir MF, Dewi A. Development of Eco-friendly Self-compacting Concrete Using Fly Ash and Waste Polyethylene Terephthalate Bottle Fiber. Civil Engineering Journal. 2023;9(2):437-52. https://doi.org/10.28991/CEJ-2023-09-02-014
  5. Bakare M, Shahu J, Patel S. Complete substitution of natural aggregates with industrial wastes in road subbase: A field study. Resources, Conservation and Recycling. 2023;190:106856. https://doi.org/10.1016/j.resconrec.2022.106856
  6. Rangan PR, Tumpu M, Mansyur M, Mabui D. Assessment of Fly Ash-Rice Straw Ash-Laterite Soil Based Geopolymer Mortar Durability. Civil Engineering Journal. 2023;9(06):1456-70. https://doi.org/10.28991/CEJ-2023-09-06-012
  7. Singh S, Patel S. Development of angular-shaped lightweight coarse aggregate with low calcium fly ash using autoclave curing-Experimental and microstructural study. Journal of Building Engineering. 2023;79:107860. https://doi.org/10.1016/j.jobe.2023.107860
  8. Al-Hindawi LAA, Al-Dahawi AM, Sh J Al-Zuheriy A. Use of Waste Materials for Sustainable Development of Rigid Pavement. International Journal of Engineering, Transactions A: Basics,. 2023;36(10):1919-31. https://doi.org/10.5829/ije.2023.36.10a.16
  9. Nistratov AV, Klimenko NN, Pustynnikov IV, Vu LK. Thermal regeneration and reuse of carbon and glass fibers from waste composites. Emerg Sci J. 2022;6:967-84. https://doi.org/10.28991/ESJ-2022-06-05-04
  10. Singh S, Patel S. Potential Use of Fly Ash for Developing Angular-shaped Aggregate. International Journal of Engineering, Transactions C: Aspects. 2023;36(6):1114-20. https://doi.org/10.5829/ije.2023.36.06c.09
  11. Joshi AR, Patel S. Application of Class C Fly Ash and Quarry Dust Mix for Utilization as Subbase Material in Flexible Pavement. International Journal of Engineering, Transactions C: Aspects. 2023;36(9):1597-604. https://doi.org/10.5829/ije.2023.36.09c.02
  12. Bijen J. Manufacturing processes of artificial lightweight aggregates from fly ash. International Journal of Cement Composites and Lightweight Concrete. 1986;8(3):191-9. https://doi.org/10.1016/0262-5075(86)90040-0
  13. Shahane HA, Patel S. Influence of curing method on characteristics of environment-friendly angular shaped cold bonded fly ash aggregates. Journal of Building Engineering. 2021;35:101997. https://doi.org/10.1016/j.jobe.2020.101997
  14. Terefe TO, Tefera GA. Design of impact stone crusher machine. Int J Sci Eng Res. 2019;10:904-9.
  15. Räisänen M, Mertamo M. An evaluation of the procedure and results of laboratory crushing in quality assessment of rock aggregate raw materials. Bulletin of engineering geology and the environment. 2004;63:33-9. https://doi.org/10.1007/s10064-003-0218-1
  16. Eloranta J. Influence of crushing process variables on the product quality of crushed rock: Tampere University of Technology; 1995.
  17. Briggs C, Evertsson CM. Shape potential of rock. Minerals Engineering. 1998;11(2):125-32. https://doi.org/10.1016/S0892-6875(97)00145-3
  18. Bengtsson M, Evertsson CM. An empirical model for predicting flakiness in cone crushing. International Journal of Mineral Processing. 2006;79(1):49-60. https://doi.org/10.1016/j.minpro.2005.12.002
  19. Concrete ACC-o, Aggregates C. Standard specification for coal fly ash and raw or calcined natural pozzolan for use in concrete: ASTM international; 2013.
  20. Standard I. Determination of water content-dry density relation using heavy compaction. 1983.
  21. Transport IMoR, Highways, editors. Specifications for road and bridge works2013: Indian Roads Congress.
  22. IS. Methods of test for aggregates for concrete. Indian Standard, Bureau of Indian Standards New Delhi, India; 1963.
  23. BIS. IS 2386 (Part 4): Methods of test for aggregates for concrete–mechanical properties. BIS New Delhi, India; 1963.
  24. Fladvad M, Onnela T. Influence of jaw crusher parameters on the quality of primary crushed aggregates. Minerals Engineering. 2020;151:106338. https://doi.org/10.1016/j.mineng.2020.106338