文摘
Sand-bentonite mixtures are used as a low permeability barrier in landfills. Due to evaporation of water, bentonite shrinks which results in a increase of the hydraulic conductivity and a decrease of the strength of the mixture. Recently, scrapped tyre chips are mixed with sand and bentonite mixture to decrease the desiccation shrinkage. Due to addition of tyre chips, the properties of the mixture may get seriously affected and become unsuitable as a liner material. Hence, it is quite essential to investigate the influence due to addition of the tyre chips on various geotechnical properties of mixture of sand and bentonite. A series of triaxial, consolidation and unconfined compressive strength experiments were carried out to study consolidation and hydraulic properties of mixtures of sand and bentonite reinforced with waste tyre chips. Bentonite and sand mixed in the proportion of 90% sand and 10% bentonite were mixed with 5, 10 and 15% of tyre chips. The results showed that the effective cohesion was increased up to 10% tyre chips content in the mixture and remained almost constant thereafter. It was also observed that the effective internal frictional angle increased due to addition of tyre chips. Post peak drop was less as the tyre chips percentage increased. However, the compressibility was found to decrease at 5 and 10% tyre chips content and slightly increased with further addition of tyre chips. The peak pore water pressure ratio was continuously decreased at all percentage of tyre chips. Failure strain was improved when increasing the tyre chips content in the mixture. Hydraulic conductivity and coefficient of consolidation was increased when increasing the tyre chips proportion in the mixture at all consolidating pressures.