Study of strain-hardening behaviour of fibre-reinforced alkali-activated fly ash cement

This paper presents a study of parameters affecting the fibre pull out capacity and strain-hardening behaviour of fibre reinforced alkali activated cement (AAC) composite. Based on a numerical study using Taguchi’s design of experiment (DOE) approach, the effect of parameters on the fibre pull out capacity was identified. The fibre pull out force between the AAC matrix and the fibre depends greatly of the fibre diameter and embedded length. The fibre pull out test was conducted on alkali activated cement with a capacity in a range of 0.8 to 1.0MPa. The strain-hardening behaviour of alkali activated cement was determined based on its compressive and flexural strengths. While achieving the strain-hardening behaviour of the AAC composite, the compressive strength decreassd, and fine materials in the composite contributes to decreasing in the flexural strength and strain capacity. The composite critical energy release rate in AAC matrix was approximately 0.01kJ/m2 based on a nanoindentation approach. The results of flexural the performance indicate that the critical energy release rate of alkali activated cement matrix should be less than 0.01kJ/m2 to achieve the strain-hardening behaviour.