Assessment of Dispersion Potential of Discarded Coconut Fibres in Concrete Pavements

Natural fibres (coir) have been preferred over their counterparts on account of lower cost, renewability, and accessibility of supply. Generally, Coir fibre, having a length greater than 50 mm is considered for various civil engineering applications and the shorter ones are typically discarded/incinerated. The use of these Discarded Coir Fibres (DCF) for concrete pavements seems to be a sustainable approach. However, their lower densities and hydrophilic nature make concrete manufacturing a challenge. To address this, a framework has been developed in the present study, primarily to uniformly distribute the DCF in concrete. The present study investigates the distribution of coir fibres in fresh concrete as well as in the hardened state. Coir fibre of lengths 10 and 50 mm with a dosage of 0.1, 0.4, and 0.7% by volume of concrete was used, considering different mixing approaches. The coefficients of variation (%) are quantified to assess the distribution of DCF in the fresh concrete and the results revealed that the dispersion of DCF in concrete decreases with an increase in length and dosage. Hardened concrete fracture surfaces were evaluated to assess fibre dispersion and orientation. The fibre density was found to be less in concrete with a low volume of fibre dosage, while more in a high volume of fibre dosage. Further, it was observed that fibre density was higher in the perpendicular direction to the casting face.