Performance evaluation of low volume synthetic fibres in pozzolanic cement concrete

Sustainable and resilient construction materials are key factors influencing the structural integrity and durability of concrete. Incorporation of polypropylene fibres has become a pivotal strategy to improve shrinkage reduction and crack resistance. The necessity of intensified exploration pertaining to synergistic use of polypropylene fibres with different cementitious materials led to the formulation of this study. 12 mm polypropylene fibres with low volume dosage 0.1%,0.2% and 0.3% with respect to concrete volume was optimized. The combination included commercially available binders like Ordinary Portland cement (OPC) and Portland pozzolana cement (PPC) for which fibrous concrete (M40 grade) behavior was investigated. Compressive strength had inverse relation with fibre dosage, 0.2% fibre dosage in OPC and PPC concrete showed marginal similarity with control non fibrous mixes with a strength of 52.24 MPa and 47.7MParespectively. Split tensile strength improved up to 3.7% and 6.4% for 0.3% fibre dosage in OPC and PPC concrete respectively. Overall improvement of flexural strength was marginal up to 2% and 8.2% for 0.3% fibre dosage in OPC and PPC concrete respectively. The results depicted the synergistic combination of pozzolans and fibres. Good quality concrete with pulse velocity range between 3.75 km/s–4.40 km/s was observed for all the set of variations reaffirming the suitability of concrete in structural applications. However, it is observed that permeability increase was within 20% for both the set of concrete with varying fibre dosages. Microstructure image depicted balling of fibres for 0.3% dosage of fibres.