Use of natural fibrous plaster for improving the out of plane lateral resistance of mortarless interlocked masonry walling

Previous studies had shown that the addition of fibres to masonry elements, (i.e. blocks, mortar and plaster), improved their mechanical properties compressive, shear and tensile strength by factors of typically 0.50, 4.25 and 3.0 respectively. The use of natural fibres within plaster did more to enhance the wall strength than fibres within blocks or mortar. In this study, the effectiveness of natural fibrous plaster for improving the out of plane lateral resistance of mortarless interlocked masonry walling was evaluated. Using 1.5 m high columns, the comparisons of mechanical parameters (like elastic stiffness, first crack load, and toughness index) were carried out. Experimental work was concentrated on fibrous plasters. Non-plastered, plain-plastered and fibrous-plastered masonry columns were compared, using both sisal fibres and rice straw. The factor of increase in failure loads over unplastered columns was found to be up to 5 times for plain and up to 21 times for fibrous plastering.