DYNAMIC PROPERTIES AND LIQUEFACTION POTENTIAL OF GRAVEL-TIRE CHIPS MIXTURE (GTCM)

Abstract

 More than one million tonnes of tires are discarded in Japan annually. Stockpiling of scrap tires in landfills may cause serious environmental and health problems. Reusing or recycling of waste tires can significantly contribute to reduction of waste product's destructive environmental footprint. Scrap Tire Derived Materials (STDM) have interesting physical and mechanical properties that make them suitable for civil engineering applications like rubberized concrete productions, slopes protection and stabilization, light weight backfill for retaining walls and subbase material for foundation of structures. STDM and sand-STDM mixture are largely being used and investigated in literature. However high compressibility and low elastic modulus of tire chips and sand and STDM mixture could result in high differential settlement and inadequate bearing capacity of foundation. In order to solve the aforementioned issues, Gravel-Tire Chips Mixture (GTCM) as an alternative geomaterial has been introduced by Hazarika et al. (2016). However, geotechnical structures reinforced with GTCM might be subjected to dynamic, repetitive or impact loads such as earthquake, blast, traffic loads. So design, evaluation and maintenance of such structures needs an investigating of dynamic behavior such as shear modulus and damping ratio and liquefaction potential of Gravel Tire Chips Mixture. A series of consolidated-undrained cyclic triaxial tests were performed on gravel and GTCM specimens to examine the influence of gravel fraction and effective confining pressure on their dynamic behavior as well as liquefaction resistance. Test Results have shown that initial shear modulus and liquefaction resistance are highly influenced by gravel fraction in GTCM. Furthermore, GTCM samples possesses a higher liquefaction resistance at low confining pressure. Samples exhibits GTCM and tire chips like behavior with high deformability as tire chips inclusion increases in mixture. Additionally, a new empirical expression is presented relating the maximum and minimum void ratio to the gravel fraction in GTCM specimens.