Effects of Glass Fiber on Recycled Fly Ash and Basalt Powder Based Geopolymer Concrete

Çelik A. İ., Özkılıç Y. O.

CASE STUDIES IN CONSTRUCTION MATERIALS, vol.11, no.1, pp.1-20, 2023 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 11 Issue: 1
  • Publication Date: 2023
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC, Directory of Open Access Journals
  • Page Numbers: pp.1-20
  • Kayseri University Affiliated: Yes


This experimental study encompasses a comprehensive exploration of multiple parameters aiming to enhance the strength, workability, setting time, and environmental attributes of geopolymer concrete (GPC). A pivotal solution lies in substituting fly ash with waste basalt powder, not only reducing binder costs but also ameliorating the overall ecological footprint. A secondary significant factor entails the integration of trimmed glass fibers. Throughout the experimentation process, the predominant geopolymer concrete binder and fly ash underwent substitution with basalt powder at proportions of 25%, 50%, and 75%. The mixtures were augmented with glass fibers of 3 mm, 6 mm, and 12 mm lengths, introduced at ratios of 0.5%, 1%, 2%, and 3%. Following this, the acquired samples were subjected to a 24-hour curing regimen in an 85°C oven. Subsequently, after a 7-day period of exposure to external conditions post-incubation, these samples tested encompassing both compressive and flexural strength tests. Samples incorporating a basalt ratio of 50% showcased the highest capacities, contrasting with reduced capacities when the basalt ratio was elevated to 75%. Conversely, samples utilizing a NaOH molarity of 12 M demonstrated superior performance. Impressively, compression strength exceeding 40 MPa was achieved with the amalgamation of 12 M and a 50% basalt additive. However, workability experienced a notable reduction at fiber ratios of 2% and 3%. Molarity concentrations did not impede slump, workability, or setting time. A consistent setting time of 6 hours was attained, and the desired workability was achieved without the need for a superplasticizer. For achieving the optimal triad of workability, setting time, and strength, while maximizing the environmental advantages of GPC concrete, the recommendation is to incorporate a distinct combination comprising 1-2% glass fibers (with a 12 mm length), 12 M NaOH, and a 50% basalt powder into the mixture formulation.