Behaviour of fibre reinforced EPS lightweight concrete under dynamic splitting tension

Abstract

Incorporating fibres into EPS lightweight concrete (EPSLC) is an effective method to enhance its strength, toughness, and impact resistance, making it more promising for applications in protective engineering. In this paper, fibre reinforced EPSLC was tested under dynamic splitting tension at strain rates ranging from approximately 4.6 s-1 to 17.5 s-1 using a split Hopkinson pressure bar (SHPB) device. The fibres used were steel fibres (SF) at volume fractions of 0.4% and 0.8%, lightweight fibres including basalt fibres (BF), polypropylene fibres (PPF), and polyvinyl alcohol fibres (PVAF) at volume fractions of 0.2% and 0.4%, as well as three hybrid fibre combinations consisting of 0.4%SF with 0.2% of one type of lightweight fibre. The testing results indicated that the addition of these fibres significantly enhanced both the static and dynamic splitting tensile strengths of EPSLC. Herein, EPSLC reinforced with 0.4%SF achieved the most pronounced enhancements, with a 41.56% increase in static splitting tensile strength and a 33.61%-40.70% improvement in dynamic splitting tensile strength. Furthermore, adding single fibres at a volume fraction of 0.4% or higher, or using hybrid fibres, can effectively mitigate the dynamic splitting damage to EPSLC and improve its crack resistance as well as impact toughness. Notably, the dynamic splitting tensile properties of all EPSLC specimens demonstrated a clear strain rate effect. Compared to the dynamic increase factor (DIF) of non-fibre reinforced EPSLC, SF reinforced EPSLC and hybrid fibre reinforced EPSLC showed lower strain rate sensitivities, while lightweight fibre reinforced EPSLC exhibited higher strain rate sensitivities. Finally, empirical formulas for DIF were proposed to guide the engineering applications of fibre reinforced EPSLC subjected to dynamic loads.