INFLUENCE OF FRC MIX PROPORTION WITH LOW CONTENT OF SHORT FIBRES ON THE CRACK OPENING RESISTANCE

摘要

Low content of short fibres is interesting for the practical applications from two points of view: (1) adding and mixing those fibres are easy, their uniform distribution in the concrete can be reached without balling, and (2) their impact on the price of FRC is not so significant as in the case when "normal" content of fibres (over 0.25 vol.%) is applied. But, it is well-known that low content of short fibres has limited influence on improvement in the performance of hardened FRC. Therefore, the investigations, which results are discussed in this paper, has been carried out with the main purpose to find out an influence of FRC mix proportion with low content of short fibres on the crack opening resistance. Improvement in the crack opening resistance of SFRC and especially hybrid fibre reinforced concrete with low content of short steel and polypropylene fibres was achieved by application of a high-range superplasticizer.