The present study examines the behavior of particulate rubber-sand mixtures (PRSM) due to the replacement of sand with fly ash. Particulate rubber (PR) of different gravimetric proportions (0, 10, 30, 50, and 100%) is mixed with sand and fly ash for the present study. Vibratory table technique, Proctor compaction technique, and minicompaction technique are adopted to determine a suitable method for finding the maximum dry unit weight of the mixtures. It is found that the Proctor compaction technique is suitable for PRSM and minicompaction technique is suitable for particulate rubber-fly ash mixtures (PRFM). Direct shear tests are carried out on the samples prepared at a relative density subjected to three different effective normal pressures. The tests results show that PRFM possesses higher shear strength, lesser compressibility, and higher shear stiffness than PRSM when PR content is more than 10% in the mixtures. Microstructure study shows that the higher strength of PRFM is attributed to the more interparticle contacts between PR and fly ash. © 2018 American Society of Civil Engineers.