Impact of various sands and fibres on the physical and mechanical properties of earth mortars for plasters and renders

Earth plasters and renders tend to crack and crumble due to weathering. Their resilience can be improved by adding sand or fibre to the earth mixture. This paper presents an extensive literature review on earth mortar studies and the results of some experiments to strengthen the earth mortars with different sands and fibres. These experiments showed that regardless of the type of fibre or sand used, the impact on shrinkage was positive but negative on mechanical strength. Although 5% chaff improved flexural and compressive strength, increasing fibre content to > 10% reduced compressive strength, and to > 20% also reduced flexural strength