Experimental investigation of flexural enhancement of RC beams with multi-walled carbon nanotubes

Abstract

This paper presents experimental tests to investigate the flexural behavior of reinforced concrete beams with multi-walled carbon fiber nanotubes MWCNTs content. The variable considered in the study is the percentage of the MWCNTs, which are 0, 0.25, 0.5, 0.75, and 1% by cement weight. The mechanical properties of the concrete mix were investigated including the compressive strength, splitting strength and flexural strength. Five simply supported RC beams were tested under four point bending test. The flexural behavior was determined in terms of load-deflection capacity, failure load, strain distribution and crack patterns. The results show that the mechanical properties of the hardened concrete were enhanced when adding MWCNTs to the mix. The highest improvement was identified when MWCNTs equals 1% that the increase in compressive strength, splitting strength and flexural strength was 38.5%, 48.4% and 56.7%, respectively. Adding MWCNTs enhances the flexural behavior of RC beams by increasing the ultimate load carrying capacity up to 29% of the reference beam. Also, the ductility of the beams were enhanced due to the Nano particles bridges the cementitious materials which limit the crack propagation and delay the failure, the flexural failure was the general mode for all the tested beams.

Keywords

• Flexural strength
• Multi-walled carbon nanotubes
• RC beam
• Strain distribution