Performance of CO₂ sequestrated recycled concrete fine aggregate in cement mortar

¹ Post-Graduate Student, Department of Civil Engineering, VNR Vignana Jyothi Institute of Engineering and Technology, Hyderabad, Telangana State, India.
² Assistant Professor, Department of Civil Engineering, VNR Vignana Jyothi Institute of Engineering and Technology, Hyderabad, Telangana State, India.
³ Civil and Architectural Engineering Section, Department of Engineering and Technology, University of Technology and Applied Sciences, Sultanate of Oman.

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Abstract

The increasing carbon footprint of construction industry has demanded the use of sustainable materials in construction. The volume of Construction and Demolition (C&D) waste is steadily increasing all over the world due to the ageing infrastructure. At the same point, the demand for new infrastructure requires huge production of concrete. The Recycled Fine Aggregate (RFA) obtained from the crushing of C&D waste can be used in the production of concrete as replacement to natural fine aggregate i.e. river sand. This is a sustainable substitute for alternative to natural river sand. In this study, the RFA is CO₂ sequestrated which improves its properties. The RFA was CO₂ sequestrated with three concentrations (0%, 5%, and 20%) and was used at different levels (0%, 25%, 50%, and 100%) of replacement to natural river sand. Cement mortar cubes of 50 mm size were cast and tested for compressive strength at 1, 3, 7 and 28 days of age. The workability of the cement mortar i.e. consistency was studied through flow table test. The effect of carbonation and replacement percentage on the compressive strength of cement mortar specimens was studied. The results indicate that CO₂ sequestered RFA can be utilized as a viable substitute to natural river sand in mortar production, providing both mechanical and environmental advantage.