Strength and stress-strain characteristics of fibre reinforced cement stabilised rammed earth

Cement stabilised rammed earth (CSRE) is used in the construction of load bearing walls. CSRE elements under compressive loads experience sudden catastrophic shear failures. Such brittle failures shall be avoided in the CSRE structures. The addition of short discrete randomly oriented fibres to CSRE can help avoid such catastrophe failures, where the fibres can bridge across the crack and help inhibit the crack propagation. The paper deals with studies on the effect of coir fibre reinforcement on the behaviour of CSRE under compression. The influence of fibre volume fraction, cement content and moisture content on the strength and stress-strain characteristics of CSRE has been investigated. Five fibre volume fractions (V-F), 0.0, 0.5, 1.0, 1.5 and, 2.0%, two cement contents (7 and 10%), and two moisture conditions were considered. The compressive strength of fibre reinforced CSRE increased by 10-30% for 1% V-F. The strain at peak stress and the failure strains have significantly increased with the addition of fibres indicating the improved ductility and the post peak response of the material. The energy absorption capacity of CSRE increased by 2-5 times for an increase in the fibre volume fraction from 0 to 2%. The sudden catastrophic shear failures observed in the cement stabilised rammed earth under compression can be eliminated by the addition of short randomly oriented coir fibres. The fibre volume fraction of 1% is the optimum.

Automated summary

The study focuses on the reinforcement effect of coir fibers on CSRE, revealing that adding 1% fiber volume fraction can enhance the compressive strength of CSRE. The addition of fibers also improves the ductility and energy absorption capacity of the material.