Assessing the impact of recycled carpet waste (RCW) on unconfined compressive strength (UCS) and ultrasonic pulse velocity (UPV) in cement-stabilized sandy soil: an experimental study

Improving soils with cement and recycled materials is a proven and effective method for enhancing mechanical properties and promoting sustainability. This study aimed to investigate the combined effects of cement and recycled carpet waste (RCW) on improving the mechanical properties of sandy soil. The experimental program was designed to evaluate the influence of varying percentages of cement and RCW. Cement was added at three levels: 3%, 6%, and 9% by the dry weight of the soil. RCW was incorporated at 0.5%, 1%, and 1.5% by the dry weight of the soil. Two key tests were conducted to assess the performance of the treated samples: unconfined compressive strength (UCS) and ultrasonic pulse velocity (UPV). These tests were selected to evaluate both the strength and the internal structural integrity of the stabilized soil. All samples were prepared and cured under controlled conditions, with a curing period of 28 days at standard laboratory temperature. The optimal combination of 1% RCW and 9% cement achieved the highest UCS and mechanical enhancements, with UPV results validating these findings. This environmentally friendly and cost-effective method is well-suited for construction applications.