Mechanical and durability studies on fly ash based fibre reinforced concrete

The purpose of this study is to determine the fresh and hardened properties of fibre reinforced concrete along with durability properties with steel fibres (SF) and jute fibres (JF). This study presents properties of concrete prepared with Fly ash (FA) as a partial replacement to Ordinary Portland Cement along with the fibres. Concrete mix of M30 grade was prepared as per IS code guidelines. The specimens were prepared with 5, 10, 15 and 20 % Fly ash replacements along with 0.5, 1.0, 1.5 and 2.0 % Steel and Jute fibre replacements with respect to the binder. For comparison, control concrete mix corresponding to M30 grade was prepared with 0% FA and 0% fibres. Variation in workability with the addition of fibres was determined with the help of slump cone test. Various mechanical strength tests were conducted on the specimens to observe that the strength was enhanced due to addition of fibres. Ultra-sonic pulse velocity test was conducted to determine the strength of prepared specimens in non-destructive way and compared with destructive compression strength values. Durability tests - Carbonation, Acid attack, Sorptivity and Rapid chloride ion penetration tests were conducted to determine the optimum percentage of fibre replacement along with fly ash replacement for long term durability. According to the experimental results, adding 15% fly ash and 1.5% fibres enhanced the mechanical properties, whereas adding 10 and 15% fly ash, 1.5 and 2.0% fibres enhanced the durability properties in comparison with the properties of conventional concrete. This paves the way for developing sustainable alternatives in the construction industry by utilization of marginal materials such as fly ash and jute fibres.