Production of eco-friendly concrete incorporating rice husk ash and polypropylene fibres

The use of supplementary cementitious materials (SCMs) has increased over the years due to the carbon footprint associated with the production of cement, which contributes to 10% of  the total global CO₂ gas emissions. This causes an increase in global warming, and the exponential increase in demand for construction of concrete has caused depletion of natural resources. Furthermore, due to increased urbanisation, large quantities of agro-industrially processed waste materials are generated and dumped into landfills, causing significant land scarcity, environmental issues, and pollution. Therefore, it has become necessary to reduce the CO₂ emissions by reducing our dependency on cement as a binder and developing eco-friendly concrete using alternative binders from agro-industrial waste materials. This study utilises Rice Husk Ash (RHA) as SCM and reinforcing with polypropylene (PP) fibres. The cement content is replaced with 5 to 20% RHA with an increment of 5% while reinforcing with PP fibres ranging from 0.20 to 0.30%. Based upon the results, it can be observed that concrete incorporating 15% RHA and reinforced with 0.25% PP fibres achieved better performance than the specimen with no SCM. However, a further increase in RHA content decreased concrete strength, which could not be recovered entirely with the reinforcement of PP fibres, though concrete with higher (20%) RHA reinforced with PP fibres could be used for non-structural and low-cost construction.