Influence of jute fibre and cement on the mechanical properties of raw earth mortar

In recent years, there has been an increased focus on the research of earthen construction, driven by the rising demand for low-cost and sustainable building materials. Numerous studies have investigated the properties of compressed earth blocks (CEBs), however, very few have examined the properties of earth-based mortar. Mortar is an essential component and further investigation is required to enhance the mechanical performance of CEB structures. The study focuses on raw earth mortar (REM), which is a rudimentary mix of water with natural earth consisting of sand, silt and clay. Through experimental investigation, the fresh and hardened properties of three REM mixes were examined to determine the influence of cement stabilisation and jute fibre reinforcement. Shear triplet CEB assemblages were manufactured and tested to determine the initial shear strength of each mortar mix. The addition of 20 mm jute fibre at 0.25% by weight increased the compressive and flexural strength of cement-stabilised raw earth mortar by 12% and 20% respectively. The addition of jute fibre also enhanced the initial shear strength, angle of internal friction and coefficient of friction during shear triplet testing. Finite element analysis (FEA) was undertaken to model the failure mechanism of the CEB assemblages, employing the use of cohesive zone modelling. The results of the FEA provided a satisfactory correspondence to the behaviour observed during experimental analysis and were within ± 5.0% of the expected values. The outcome of this investigation demonstrates the potential of REM and contributes to the development of low-cost and sustainable earth construction. • Effect of cement and jute fibre on the mechanical properties of raw earth mortar • Shear triplet testing to determine the initial shear strength of raw earth mortar • Experimental analysis and numerical modelling of earth masonry assemblages • Use of cohesive zone modelling to simulate the mortar-block bond interface