Waste rice husk and sugarcane residue can be effectively utilised to partially replace cement in green concrete after thermo-chemical treatment, thereby contributing to enhanced environmental sustainability as well as promoting effective waste management and resource reuse, according to a study by Indian scientists.
“The hybrid concrete showed favourable results, improving compressive strength by 12.6 per cent and 8.2 per cent by replacing 10 per cent cement with rice husk ash and sugarcane residue, respectively, as compared to conventional concrete,” the researchers said.
“The enhancement in concrete performance is attributed to microstructural densification and certain chemical reactivity and bonding characteristics. These characteristics confirm that rice husk and sugarcane residue are effective partial cement replacements, contributing to reduced carbon emissions and promoting sustainable construction practices,” they added.
The study, undertaken by eight researchers from Central Road Research Institute, New Delhi, Symbiosis International, Pune, K.R. Mangalam University, Gurugram, Jamia Millia Islamia, New Delhi, Al-Falah University, Faridabad, and King Faisal University, Saudi Arabia, was published in ‘Scientific Reports’, a peer-reviewed journal, on June 25.
Observing that countries in tropical regions with high annual agricultural production have generated large quantities of agricultural residues which are often disposed of through unsuitable methods, the researchers said. This presents a major difficulty with respect to waste management and environmental preservation.
India, a country with rich agricultural resources, generates a large amount of biomass waste, with the total yearly biomass waste produced estimated to be more than a hundred million metric tons.
Rice husk and sugarcane bagasse are the two most significant agricultural residues, the researchers noted. Recent popularity for sustainable and cleaner fuels has diverted attention to biomass utilisation and among these, biomass gasification has emerged as a sustainable waste management option for agricultural waste.
Biomass gasification has several benefits such as low cost, renewable nature, ready availability, and easier conversion. Biomass is partially oxidised under oxygen-limited conditions and produces a combustible gas termed syngas, which can be subsequently used to generate electricity in engines or gas turbines, thereby reducing environmental pollution and providing useful energy from waste, the researchers said.
At the same time, the researchers pointed out that the world market for biomass gasification is estimated to grow substantially at an expected compound annual growth rate of approximately 21.5 percent between 2023 and 2028, as India strives to meet its renewable energy goals.
Recent studies have also confirmed that thermochemical upgrading of agro-by-products can improve their fuel characteristics, thereby increasing their suitability for thermal power plants and biomass-to-energy applications.
The waste ash of these biomasses can be used as green concrete in construction.