This paper reports an investigation on the use of recycled rubber tires in producing normal- and high-strength concretes under tropical conditions, as experienced in Singapore and the Asia region. The tests performed on fresh concrete were a slump test and a determination of unit weight and air content. Tests on hardened concrete were nondestructive tests that included measurements of hardened density and ultrasonic pulse velocity; and destructive tests that covered a cube test to obtain the compressive strength of concrete, and an axial compression test on concrete cylinders to determine their stress-strain curves. The effects of water-cement ratio (w/c), rubber as aggregate replacement, rubber type, mineral admixture as cement replacement, steel fiber reinforcement, and curing age on the properties of rubberized concrete were assessed and compared. Recommendations were given on the applications of normal- and high-strength concretes containing recycled rubber in relation to their fresh and hardened properties.