Influence of fibers on fresh properties and compressive strength of geo-polymer concrete

Abstract

Geopolymer concrete (GPC) is a sustainable construction material that can be used as a substitute for conventional cement concrete. Several factors influence the performance of GPC such as, the type of binder material used, the molar concentration of the activator solution, and the curing conditions. The main purpose of this work is to develop fiber reinforced GPC by utilising various fibers that to reduce brittleness. The proposed work is divided into two phases. In the first phase, experiments are conducted to evaluate the significant impact of partial replacement of Ground Granulated Blast Furnace Slag (GGBS) with low-calcium fly ash on workability and compressive strength of GPC optimizing the amount of GGBS required for the development of M35 and M40 grade GPC under ambient curing. In the second phase, the performance of crimped steel fiber, polypropylene fiber and basalt fiber in terms of workability and compressive strength were evaluated. Crimped steel fiber containing by volume of binder (0.4%, 0.45%, 0.5%, 0.55% and 0.6%), polypropylene fiber containing by volume of binder (0.05%, 0.1%, 0.15%, 0.2% and 0.25%) and basalt fiber containing by volume of binder (0.1%, 0.15% 0.2%, 0.25%, 0.3% and 0.35%) are used in the experiment. NaOH with 8 M and 12 M with Na2SiO3 were used as an alkaline solution to develop GPC and cured in the ambient curing for 7 days and 28 days respectively. It was observed that increase in the percentage of GGBS decreased the workability, but the compressive strength is increased. The effect of fibers on workability and compressibility has been observed, and it has been found that workability decreases with the increase of fibers in the GPC. Compare to crimped steel fiber, basalt fiber the workability of GPC is highly affected due to the addition of polypropylene fiber. In comparison crimped steel fiber and polypropylene fiber, concrete with salt fiber exhibited higher compressive strength.