Influence of engineering fibers on fresh and mechanical properties of geopolymer concrete

Abstract

Geopolymer concrete (GPC) is gaining popularity due to its sustainable nature, and therefore it is called as “green” concrete, but it is more brittle than conventional concrete. To reduce the brittleness in GPC, the fibers must be added. Fiber-reinforced concrete (FRC) is gaining popularity for practical engineering applications due to its excellent tensile strength, flexural strength, durability, and fracture properties. However, applying FRC to infrastructure projects and construction requires a thorough understanding of FRC's workability and mechanical properties. In the current study, the primary objective is to determine the optimum amount of fiber such as basalt fiber (BF), crimped steel fiber (SF), and polypropylene fiber (PF) required for the development of GPC (M35 and M40 grade GPC). The present work is divided into two stages. The slump test, tensile strength test (TS), and flexural strength test (FS) are used in the first stage to obtain optimized fiber dosage after 7 and 28 days of ambient curing. In the second stage, the optimized fibers are used to evaluate the compressive strength (CS) of GPC. The alkaline binder includes FA and GGBS, and the concentration of NaOH is 8 M and 10 M, respectively. The test results demonstrate that as the volume of fiber content increases, each fiber's workability decreases gradually. In the case of 8 M and 10 M of NaOH, as compared to GPC-BF and GPC-PF, the TS and FS of GPC-SF showed maximum strength, ranging between 120.71% and 109.77%. In the case of CS, the BF-based GPC exhibited the highest strength in 8 M and 10 M, with a range of 16%.