Use of short fibres in structural concrete to enhance mechanical properties

Abstract

The purpose of this research is based on the investigation of the use of short fibres in structural concrete to enhance the mechanical properties of concrete. The objective of the study was to determine and compare the differences in properties of concrete containing no fibres and concrete with fibres, as well as the comparison on the effects of different type and geometry of fibres to the concrete. This investigation was carried out using several tests, which included workability test, compressive test, indirect tensile test, flexural test and modulus of elasticity test. A total of ten mix batches of concrete containing 0%, 0.5%, 1.0% and 1.5% fibre volume dosage rate on 'wave cut' steel fibres, high performance polypropylene fibres and Fibremesh were tested to determine the enhancement of mechanical properties of concrete. The workability of concrete significantly reduced as the fibre dosage rate increases. This was assessed through standard slump test, compacting factor test and VEBE consistometer test. Results of compressive strength test indicated that the use of fibre in concrete might not efficiently increase in strength. In flexural and indirect tensile test showed specimens with fibres that drastic increase in strength from specimens without fibres. A moderate increase in modulus of elasticity of the fibre reinforced concrete was indicated in modulus of elasticity test. The usage of fibres were fully utilised when it comes to post-cracking stage, as it increase on ductility and toughness of concrete. This was examined through the load/deformation curve of flexural strength test and stress/strain diagram of modulus of elasticity test. It was found that different type and geometry of fibres influence the mechanical properties of concrete in a different manner. As to create a cost efficient fibre reinforced structure, these changes on fibres are vital to the design and construction. However, further investigations were highly recommended and should be carried out to understand more mechanical properties of fibre reinforced concrete.