Experimental analysis of pre-processing methods to improve natural fibre performance in concrete

Natural fibres such as sisal and coir are used as reinforcements in concrete to enhance its mechanical properties. In this investigation, pre-treatment techniques of these fibres were studied to enhance their performance in concrete applications. Chemical treatments using sodium bicarbonate and sodium hydroxide solutions have been adopted to modify the surface texture of sisal and coir fibres. Fourier transform infrared spectroscopy of treated and untreated sisal fibre shows there is removal of the hemicellulose part of the fibre. SEM analysis indicated that the removal of the outer layer of cellulose from the fibre leaves behind a rougher surface that enhances the bonding capacity with the cement matrix. A change in morphology is seen after chemical treatment, as shown by the analysis through SEM, which depicts an improved roughness on the surface; also the cost comparison between the synthetic fibre and pre-processed natural fibre is observed. This results in better load transfer and, thus more durable concrete structure.