Structural behaviour of recycled aggregate SCC RC beams with hollow cores

• Main Authors: Hassan, Mustafa R., Khudhair, Jamal A.
• Format: Conference Proceeding
• Language: English
• Subjects: Concrete aggregates; Ductility; Energy absorption; Structural behavior; Ultimate loads; Ultimate tensile strength
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0207175

This paper investigates the possibility of using recycled aggregate in concrete beams with hollow cores. The main variables considered in the experimental study were the recycled aggregate percentage and the hollow core shape. Eighteen beams were thus fabricated and tested, with results that showed that the addition of recycled aggregate in the concrete beams affected the ultimate strength, ductility, and energy absorption of the concrete members. An increase in the recycled aggregate percentage to 25% decreased the ultimate strength capacity by 9.5%, while a further increase to 50% led to a decrease in the ultimate strength of about 15%. For SCC beams made with 25% recycled aggregate, the hollow core had a greater effect, particularly on the ultimate strength as compared with the beams made without recycled aggregate. The decrease in the ultimate load capacities were 8.1%) and 12% for the beams with circular and rectangular hollow cores, respectively, for beams with 25% aggregate, while these percentages were 13.5% and 15.6% for beams with 50% replacement. The ductility and energy absorption both decreased as the replacement ratio of recycled aggregate increased. The increases in recycled aggregate ratio from 25% and 50% increased ductility by 45% and 416%, respectively; however, while the increase in recycled aggregate ratio to 25% caused an increase in energy absorption by 16.7%, this decreased by 13.1% when the replacement ratio increased to 50%. The existence of a hollow core reduced the ductility index, which decreased from 2.06 for the solid beam to 1.9 and 1.47 for the hollow beams with rectangular and circular openings, respectively.