Effect of addition of tire chips on the unconfined compressive strength of fly ash-lime-gypsum mixture

Standard Proctor compaction tests were carried out to obtain the optimum reference mix containing fly ash + 8% lime + 0.9% gypsum. The result of light compaction study reveal that addition of small percentage of gypsum (less than 1%) to the fly ash + 8% lime mix has no effect on the dry unit weight and optimum moisture content. The reference mix so obtained was mixed with randomly distributed dry/wet tire chips to study the unconfined compressive strength, energy absorption capacity and cracking pattern of the specimen by varying the tire chip content (5% to 15%), curing period (7 days to 180 days) and curing methods. The results of this study indicated that unconfined compressive strength, energy absorption capacity and cracking pattern of the reference mix containing dry/wet tire chips is influenced by the tire chip content, curing period and curing method. The study further reveals that the unconfined compressive strength and energy absorption capacity of specimen can be increased using wet tire chips in comparison to dry tire chip in the reference mix. Study on unit weight reveals that it decreases with the increase in tire chip content in the reference mix. Further the specimens containing 5% dry/wet tire chip content were observed to fail by development of multiple cracking where as specimen with higher percentage (15%) of dry/wet tire chips results in zig-zag cracking behavior of the specimen. The reference mix with wet tire chips can be a good material for road sub base having light traffic and disposal of these materials will be in an environmental friendly manner.