Experimental Investigation on the Compressive Behavior of Rubber-Sand Mixtures under Repeated Loading-Unloading

Due to the behavior of low-density and high-energy absorption efficiency, rubber materials are now being extensively applied to solve geotechnical problems. In order to ensure the rational and economical use of rubber sand mixtures in geotechnical engineering, it is necessary to systematically study the compression behavior of rubber sand mixtures, especially under repeated loading-unloading mode. In this study, three series tests, including one-dimensional compression tests and repeated loading-unloading tests, were conducted on rubber sand mixtures with various rubber contents. The development of the void ratio, compression coefficient, elastic strain, and plastic strain of the mixtures under different load modes was investigated. Results showed that compared to pure sand, rubber sand mixtures exhibited different compression deformation behavior. The rubber content had a significant impact on the compression behavior of rubber sand mixtures. The compression behavior of the rubber sand mixture changed from low to high compressibility when the rubber content was greater than 10%. Also, with the increase of rubber content from 0% to 20%, the ratio between elastic and plastic strain of the mixtures increased from 1:5 to 2:3. When subjected to loading and unloading cycles within a large stress range (0-1,600 kPa), the rubber sand mixture underwent significant elastic strain, and plastic strain gradually accumulated with the number of cycles. When the repeated loading and unloading test started at a certain initial pressure (800-1,600 kPa), the elastic deformation of the rubber sand mixture decreased to a smaller level and did not change significantly with the number of cycles. At this point, plastic strain mainly occurred in the first cycle, and almost no plastic strain occurred in subsequent cycles. Rubber content below 10% has lower compressibility and is a recommended rubber content (RC) value for use in engineering. In addition, setting a certain initial pressure is an effective method to reduce the elastic strain of mixtures and improve the accumulation of plastic strain in engineering applications. (c) 2024 American Society of Civil Engineers.