Performance study of fibre reinforced functionally graded concrete pipes

Abstract

The focus of the study is to develop Functionally Graded Concrete (FGC) and examine its performance in concrete pipes. FGC is concrete produced with variation in material and structure composition leading to changes in the overall behaviour of structures. In this study, functional gradation is created using micro steel fibre and basalt fibre. The FGC was prepared by varying the fibre content in concrete. The proposed functionally graded concrete consists of two-layer. One layer with fibre reinforced concrete and conventional concrete of M30 on the other side. The study has two major stages. The earlier stage is adopted to study the mechanical performance of the fibre reinforced concrete with 0.25%, 0.5%,0.75% and 1% addition of volumetric fraction to the conventional concrete mix. Compressive strength, split tensile strength, and flexural strength are taken as the mechanical parameters for consideration. FGC with a volumetric fraction of 0.75% with 0.75 h/H, where h/H ratio is the thickness of FGC to overall thickness, proved to be efficient. In the second stage, the optimum FGC is utilised to cast the Functionally graded concrete pipes (FGCP). This stage involves studying the performance of FGCP using three edge bearing tests and post crack studies. In the initial stage, Micro steel fibre reinforced concrete shows higher mechanical performance than basalt fibre, and basalt fibre shows better performance in post crack behaviour. The pipe testing indicates that micro steel fibre has higher strength aspects. Basalt fibre shows higher ductility in post crack behaviour. The micro steel fibre FGCP in strength perspective in both mechanical and post crack strength is higher than conventional concrete and Basalt FGCP.