Influence of carbon fibers on strain and damage sensing of self compacting concrete under external applied forces

Abstract

In the present study, concrete cubes of 150mm embedded with carbon fibres in different dosages (from 0% to 2% by cement mass) were cast using self-compacting concrete. Two tests were conducted, namely strain sensing and damage sensing on all the samples and co-relation between a fractional change in electrical resistance (FCR) and properties of concrete under compressive load are reported. Strain sensing test was carried out within the elastic region and the co-relationship was achieved in between the strength and change in electrical resistance over time in order to obtain the strain sensing properties of the sample. The findings acquired show that concrete specimens with fiber dosage of 1.5 percent by cement mass produce a stronger correlation between a fractional change in resistance (FCR) and concrete compressive strength which can be used as a stress detecting property. Gage factors of all the specimens were also measured throughout strain sensing tests. Following strain sensing testing, all the samples were tested for the damage sensing test by gradually applying load until failure. The relationship between stress, electrical resistances and strain is established from obtained test results. Results obtained show that the same sample comprising 1.5% fiber by cement mass is able to sense damage and can be linked to the stress-strain curve of concrete that can further be used as NDT approach to obtain stress-strain in concrete if FCR is recognized.