Concrete technological influences on the performance classes of steel fibre concrete
The perfomance capacity of steel fibre reinforced concrete, expressed by its performance classes and therefor the residual flexural strength, depends on numerous factors. Including compressive strength, fibre type and geometry, fibre content and concrete composition to name a few. A working group of DAfStb subcommittee ”Stahlfaserbeton“ set up a comprehensive database containing data of numerous initial and performance tests of steel fibre reinforced concretes from publications and suppliers, especially ready mixed concrete plants. It enables us to identify specific influences, e.g. of concrete composition or fibre properties and quantify them in general. In this contribution the influence of fibre tensile strength, fibre slimness, concrete compressive strength, concrete installation consistency, the shape of aggregates as well as the usage of reactive additives are considered. Based on the database it can be seen, that no measurable effect of crushed coarse aggregates on the residual flexural strengths can be identified compared to round aggregates. The consistencies F3 and F4 of the ready mixed concrete show no significant dependency as well. The usage of secondary reactive additives, especially fly ash, as well as cement containing blast furnace slag provides higher residual flexural strengths regarding to the database. Positive influences of the compressive strength and the fibre slenderness can be generally confirmed and quantified.