The effect of high rate of scrap tire usage on the compressive strength, flexural strength and vibration properties of lightweight and normal concrete

In recent years, due to the exponential increase in the world population, the number of discarded scrap tires has become a serious ecological problem. In addition, environmental and social damages that occur during the extraction of aggregate is one of the controversial issues of land use. For this reason, ways to solve these two problems are sought, and one of these methods is to use rubber manufactured from scrap tires instead of natural aggregate in concrete production. In this study, the effect of the use of scrap tires on the compressive strength, bending strength and vibration properties of structural lightweight concrete and normal weight concrete produced using pumice type natural lightweight aggregate was investigated comparatively. 6 different series of rubberized light and normal concrete mixtures were produced by changing the natural aggregate of the carrier light and normal concrete with 4 types of rubber (in crumb and fiber form, and of each of these two forms a fine and a coarse size) by 5%, 10%, 15% and 20% by weight. The target compressive strength of (28) days old samples was determined as 30 MPa (cube). With the increase of scrap rubber content, the decrease in compressive and flexural strength of rubberized lightweight concrete was less than that of normal rubberized concrete in all series. When the vibration test results were examined and analyzed there was unexpectedly no consistent approach to the increase or decrease in damping ratios proportional to the rubber ratios used in both concrete types.