FLEXURAL BEHAVIOUR OF STEEL FIBER REINFORCED CONCRETE SLABS ON GRADE

Abstract

This study deals with the structural characteristics of steel fibre reinforced concrete (SFRC) slabs on grade without using traditional steel reinforcement mesh under static flexural loading. The experimental program was carried out on seven slabs (2000×1500×120 mm), including six SFRC slabs with steel fibre dosages varying from 10 to 40 kg/m³ and one control conventional reinforced concrete (RC) slab. The slabs were supported by a spring system representing the elastic foundation, and a four-point loading scenario was used to investigate the response of the slabs under vehicle static loading. Experimental results of the slabs on grade demonstrated that SFRC slabs reduced the maximum relative displacement by 74–78 % and increased the service load limit (by up to 53 % compared with the RC slab. However, service loads reached 94 % of ultimate load in SFRC versus only 56 % in RC, indicating very limited reserve capacity. At the ultimate limit state, SFRC slabs exhibited 9–30 % lower ultimate loads and markedly lower ductility than the RC slab. Crack widths at failure were 76–85 % smaller in SFRC slabs than in RC slab. The results demonstrate that steel fibres can effectively replace mesh for serviceability performance, with 30 kg/m³ being the practical optimum dosage.