Cement–nanosilica stabilized fibre-reinforced rammed earth: compressive and flexure behaviour

Abstract

Rammed earth (RE) is a brittle material that can undergo sudden catastrophic failures under ultimate stress. Such sudden catastrophic failures can be avoided in RE structures with the addition of randomly oriented polypropylene fibres where crack propagation can be inhibited.Further, the strength of RE can be enhanced by the addition of nanomaterials, which make RE denser because of their high specific surface area. This research deals with studies on the effect of polypropylene fibre and nanosilica on the behaviour of cement stabilized rammed earth (CRE) under compression and flexure. The effect of fibre volume fraction and nanosilica content on the strength and stress-strain characteristics has been evaluated. Three polypropylene fibre volume fractions (0.2%, 0.3% and 0.4%) and five nanosilica contents (0.2%, 0.4%, 0.6%, 0.8% and 1%) were considered in this investigation. The compressive strength of fibre reinforced CRE increased by 30% for 0.3% of polypropylene fibre content and by 41% for 0.6% of nanosilica content when compared to CRE. The strain at peak stress has significantly increased with the addition of fibres indicating improved ductility and postpeak response of the material. The microscopic analysis showed that the addition of nanosilica has contributed to a denser packing of soil particles and hence, might have increased the compressive strength.