PERFORMANCE OF FIBER REINFORCED CONCRETE IN ACIDIC ENVIRONMENT

Abstract

An experimental investigation has been carried out of study the behavior of fiber reinforced concrete in aggressive environment condition. Concrete is very strong in compression but weak in tension. The tensile strength of concrete is less due to widening of micro-cracks existing in concrete subjected to tensile stress. Due to presence of fiber, the micro-cracks are attested. Polypropylene fiber is an inert material and is chemically resistant. So it added to concrete and then immersed in acidic environment to evaluate the properties of fiber reinforced concrete. The investigation reported in this project, was carried out to study the effects of using Polypropylene fibers in fiber reinforced concrete in acidic environments, The following types of specimen were selected for different type of tests,  Cubes for normal testing and for non destructive tests such as rebound hammer test , Ultra Sonic Pulse Velocity test etc.  Cylinder for split tensile strength test  Prism for modulus of rupture test A total of 288 numbers of concrete specimens (108 cube of size 150mm x 150mm x150mm, cylinder of size 150mm dia x 300mm height and prizm of size 100 mm x100 mm x 500mm ) were cast with and without fiber and were immersed in diluted sulfuric acid of normality 0.2N. These specimen were tested as per relevant codes of practice Bureau of Indian Standard. The pH of sulfuric acid solution was checked regularly and was maintained constant by addition of concentrated acid from time to time.

- 2 -

The mass, Rebound number, ultrasonic pulse velocity, compressive strength of cubes, split tensile strength of cylinders and modulus of rapture of prisms, made up of ordinary concrete and fiber reinforced concrete increased with time when cured in ordinary water Losses in all these parameters with time, were observed in both ordinary concrete and FRC, when cured in acidic environments, in comparison to ordinary water. Though, Losses in all the parameters increased with the time of exposure, in case of fiber concrete these were less as compared to that of ordinary concrete at any level of exposure time. Thus the FRC mixes has been proved to be more durable as compared to ordinary concrete under the acidic exposure condition.