Investigating the properties of lightweight concrete containing high contents of recycled green building materials

In this study, the cement and aggregate used in lightweight aggregate concrete were replaced with recycled green building materials (e.g., waste LCD glass sand and waste tire rubber particles). The influence of the maximum replacement amount on the fresh mixture (slump, unit weight, setting time, bleeding), hardened (compressive strength and ultrasonic pulse velocity) and durability (quadruple type resistance and length change) was investigated to determine the influence of high contents of recycled aggregate and recycled pozzolanic admixtures on the properties of the concrete. The findings showed that the addition of recycled green building materials maintained good workability of the concrete as the replaced amount increased. The unit weight was reduced by approximately 1.4 times (600 kg/m3); the setting time and bleeding rate were increased by 1.5 times (73 min and 190 min) and 1.4 times (8%), respectively. The compressive strength, ultrasonic pulse velocity and length change were reduced by 9.8 times (37.18 MPa), 1.4 times (1131 m/s) and 3.7 times (−0.115%), respectively. The resistance was increased by 1.8 times (27.8 kΩ cm). A database will be constructed in the future for related studies to facilitate an increase in waste recycling value and to maximize the environmental protection benefits.