Improvement in the flexural behaviour of road pavement slab concrete containing steel fibre and silica fume

Cracks in concrete surfaces occur because of steel bar corrosion in reinforced concrete marine structures and other infrastructures, such as pavement slabs. Recently, the use of steel fibre-reinforced concrete (SFRC) to reduce and delay cracking and increase flexure strength has attracted considerable interest. Incorporating steel fibre in concrete delays and controls the tensile cracks of composite materials. This paper investigates the effect of using steel fibre (SF) and silica fume with steel fibre on the compressive strength and flexural behaviour of road pavement slabs (RPSs). Three concrete mixtures of concrete are the first mixture (MCC) is the control mixture, the second concrete mixture (MSFRC) contains steel fibres as an additive with a fraction volume of 1%, and the third concrete mixture (MSFRC–SF) contains steel fibres with a fraction volume of 1% and silica fume with a fraction volume of 10% as an additive. In addition, the effects of the types of curing tap water (TW) and seawater (SW) on concrete were investigated. Compressive strength was assessed at 7 and 28 days, and RPS flexural behaviour was measured at 28 days. The microstructure of concrete was examined using scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The compressive strength of the mixes (MSFRC–SF) cured with TW and SW increased by 21.20% and 14.40%, respectively, compared with the control mixture (MCC). The ultimate loads for RPS–MSFRC–TW and RPS–MSFRC–SF–TW increased by about 24.29% and 46.95%, respectively, relative to the ultimate load of RPS–MCC–TW. The ultimate loads for RPS–MSFRC–SW, and RPS–MSFRC–SF–SW increased by about 36.32% and 59.90%, respectively, when the samples were tested with RPS-MCC–SW.