Growing piles of discarded tires are potential sources of fire and health hazards. The current disposal methods are wasteful and costly. As a possible solution to the problem of scrap-tire disposal, an experimental study was conducted to examine the potential use of rubber aggregate (tire chips and crumb rubber) as mineral aggregate substitute in Portland cement concrete mixes. The research focused on determining the strength characteristics of rubberized concrete and examined the relationship between the size, percentage, and shape of rubber aggregate and the strength measured.Rubberized concrete was found to possess good esthetics, acceptable workability, and a smaller unit weight than plain concrete. However, it exhibited low compressive and tensile strengths and lower resistance to repeated freezing and thawing cycles than that of plain concrete. A statistical analysis of the experimental data suggested that only the percentage by volume of rubber in the mix has a significant effect on strength. The size and shape was found insignificant. Unlike plain concrete, rubberized concrete did not demonstrate the typical brittle failure. It exhibited a ductile, plastic failure, and showed the ability to absorb a large amount of plastic energy under compressive and tensile loads. Key words: rubberized concrete, concrete properties, compression, durability, failure, modulus of elasticity, slump, tension, toughness, workability.