Investigation of mechanical and durability properties of fiber reinforced self compacting concrete

The aim of this thesis is to carry out an investigation into mechanical and durability properties of fibre reinforced self compacting concrete (FRSCC). The achievement of this aim, a control self compacting concrete (SCC) and 24 FRSCCs determined fresh concrete properties applying slump-flow, V-funnel and L-box tests were designed. In the design of FRSCC, 4 steel and 2 polypropylene synthetic fibres were used in different lengths and aspect ratios. These fibres were used as single and in combination with 2 and 4 of those fibres. In this way, not only the effect of single fibre and the synergy effect of hybrid fibres but also the size concentration effect of fibres had different dimensional properties in total fibre volume were investigated. Compressive strength, splitting tensile, flexural tensile strengths, ultrasonic pulse velocity tests and relative porosity test were carried out to determine mechanical properties of produced concretes at normal conditions. On the other hand, elevated temperature, freezing-thawing, acid resistance, wetting-drying and carbonation tests were performed to identify durability properties of produced concretes. Moreover, again all same tests applying at normal conditions were conducted out after durability tests to detect mechanical properties. Furthermore, internal structural properties of some concrete specimens were investigated through SEM image analyses.General results of thesis; an improvement was observed on fresh concrete properties with decreasing fibres length and aspect ratio in the mixes used single fibres. Another improvement was observed on fresh concrete properties when the concentration of fibres which are so long and have high level of aspect ratios in total fibres volume was decreased in the mixes designed with hybrid fibres. After mechanical tests, on the one hand, concrete series have micro fibres showed an improvement at compressive strength while concrete series have macro fibres decreased, on the other hand, concrete series have macro fibres gave higher splitting and flexural tensile strengths while concrete series have micro fibres were giving lowers. After all tests were applied it was recognised that mechanical properties of concrete series with hybrid fibres which macro fibres match to micro fibres were superior. The highest strength losses were obtained from FRSCCs which applied elevated temperature test.Key words: Mechanical properties, durability properties, fibre reinforced self compacting concrete