The effects of fibres on the shrinkage of high-strength concrete under various curing temperatures

• The addition of the fibres improves the mechanical properties of high strength concrete.
• The addition of the fibres in the high-strength concrete improves significantly the volume stability.
• The evolution of the total shrinkage is influenced by the dosage and aspect ratio of steel fibres.
• Rising the curing temperature increases the magnitude and rate of the total shrinkage.

In this paper, an experimental investigation is carried out to study the influence of the curing temperature, types of fibres, their dosages and their aspect ratios on the total shrinkage and mechanical properties of the high-strength concrete (HSC) containing steel fibres (SF) considering two aspect ratios (55, 80), polypropylene fibres (PF) and hybrid fibres (HF), exposed to isothermal curing temperatures 20 °C, 35 °C and 50 °C. Two dosages were used, 0.5% and 1% for the steel fibres, 0.1% and 0.2% for polypropylene fibres and hybridization of 0.5% for SF and 0.1% for PF. The obtained results show that the increase of the dosage of fibres reduces the total shrinkage. Hybridizing of fibres induces considerable decrease of the total shrinkage compared to single fibre types. The results of the total shrinkage show that the polypropylene fibres are more efficient than the steel fibres. Furthermore, rising the curing temperature amplifies significantly the rate and the magnitude of the total shrinkage. On the other hand, the addition of fibres improves considerably the flexural tensile strength.