Experimental study on shear responses of clay adobe beams reinforced with randomly distributed short fibres

Abstract

Adobes are a widely used masonry material for many traditional constructions, and thus many are still in use. This study examines the shear strength of three different design mixes of clay adobe with constant soil type, water content, fibre volume fraction, and compacting type. The adobe specimens were tested as beam type elements under certain loading types in order to produce internal pure shear at the central region of the adobe beam. Two different reinforcing short fibres, straw wheat fibres and nylon fibres, were added randomly to the regular clay adobes separately as the adobes were made by cutting the adobe ingots produced using a spiral compacting machine. For every type of reinforcement, the shear properties were examined in a set of innovative indirect shear tests, which included the estimation of shear modules, ultimate strength testing, and a nominal shear stress-strain diagram. The effectiveness of the fibre types on the mechanical behaviours of the reinforced adobe were thus compared with the control specimen (plain adobe). The experimental observations were recorded by means of a Digital Image Correlation (DIC) technique from an acquired 2-D DIC system in order to sketch the shear strain changes in the affected zone while applying monotonic transverse loading.