Experimental investigation of the compressive and shear behaviours of grouted and hollow masonry constructed with PVA fibre-reinforced mortar and grout

Abstract

Polyvinyl alcohol (PVA) fibres are ultra-high-performance fibres that can be used to reinforce cementitious composites. This study experimentally investigated the compression and shear behaviours of grouted and hollow masonry constructed with fibre-reinforced mortar (FRM) used for the joints and/or PVA fibre-reinforced grout (FRG). In this regard, the effect of increasing the fibre content of 6 mm PVA fibres in the FRM on the behaviour of masonry was investigated. Moreover, the effect of changing the fibre length (8 mm and 13 mm PVA fibres) and the fibre content of 13 mm PVA fibres in the FRG on the behaviour of masonry was investigated. This was accomplished by constructing and testing 31 masonry prisms and 29 masonry assemblages. The behaviour of PVA-reinforced masonry was evaluated based on compressive strength, shear strength, modulus of elasticity, modulus of rigidity, compressive strain at peak compressive stress, shear strain at peak shear stress, compression ductility index and compression toughness. In addition, the compression and shear stress-strain curves, failure modes and crack propagation of PVA-reinforced masonry were compared with unreinforced masonry. It was concluded that using PVA fibres in the grout minimized the masonry face shell spalling, and most of the post-peak deterioration appeared in the form of masonry cracks and less face shell spalling compared with unreinforced masonry. In addition, using PVA-FRM only or PVA-FRM with PVA-FRG could increase the compressive strength of grouted masonry. In contrast, using PVA-FRM did not change the compressive strength of hollow masonry. Furthermore, all grouted assemblages with PVA-FRM and PVA-FRG (except for assemblages with 13 mm PVA-FRG with a fibre content of 0.10% by weight of grout) have similar average shear strength compared with unreinforced assemblages. Finally, As the fibre content of 6 mm PVA fibres in the FRM of hollow assemblages increased, the shear strength and the modulus of rigidity decreased. This study highlights the improvements and drawbacks of using PVA Fibres in mortar and grout on the compressive and shear performances of hollow and grouted masonry.