• Ige, Olubisi
• Obas John, Prof. Ebohon
• Akinlolu, M.
• Haupt, C.

Abstract

In Nigeria, building collapses is a common occurrence, and several factors have been advanced to explain the incidents, amongst these is the lack of understanding of the functionality and mechanical properties of steel fibre reinforced concrete. Such understandings can assist in stemming building collapses and attendant economic and social effects, particularly the health and safety of construction workers and occupants. This is achieved by understanding thefunctionality and mechanical properties of steel fibre reinforced concrete. As a way of demonstration, an efficient way to achieve this is to use thin short discrete steel fibres, this will allow, a multi-directional reinforcement, the process modifying and improving properties of the concrete, especially its ductility. Critical to this, is the understanding of the preference and selection of materials to make appropriate mixes for efficient result of steel fibre reinforced concrete. In other words, failure to pay attention to selection and use of materials will produce weak concrete structure and precipitating unwarranted disasters. This study investigates the effects of length and aspect ratio of steel fibres when mixed with different sizes of coarse aggregate on the workability and subsequently, on the mechanical properties of the material. Variables selected for the study were fibre lengths of 50 mm and 60 mm, aspect ratio of 45, 50 and 60, fibre dosages of 25 kg/m³, 40 kg/m³, 50 kg/m³ and 60 kg/m³ and maximum aggregate sizes of 10 mm and 20 mm. Mix proportions for the investigation were kept constant throughout the study. Slump test was performed on fresh concrete while compressive strength was measured using 100 mm cubes and flexural performance assessed through 150 mm x 150 mm x 600 mm prism. The experimental results confirm that the combination of geometry and maximum aggregate size in the mix has an important influence on the mechanical properties of hardened concrete. It is hoped that construction practitioners in Nigeria, and by extension, Africa, will evaluate their practices in light of this study.

Topics

• impedance spectroscopy
• strength
• steel
• ductility