Rubber/crete: mechanical properties of scrap to reuse tire-derived rubber in concrete. A review

The recycling of waste tires is of paramount importance for the environment protection and for economic reasons too. The amount of scrapped tires in USA reached 550 million tires per year and it is still raising. In the EU even higher numbers are estimated reaching the value of 1 billion tires per year. Disused tires are transformed into wastes, causing a highly negative environmental impact. Tire disposal mainly involves highly polluting treatments (e.g. combustion processes for the production of fuel oil), while only a small percentage of waste (from 3% to 15%) is destined for less invasive treatments such as powdering. In this work we will see some previous study in which waste tire powder of different ranges used in combination with cement concrete mixture, providing a final product with suitable mechanical properties for the chosen engineering application. As results of previous work recorded that reaching a good compressive strength can be achieved through replacing 30% of powder tire with crush sand. First, the percentage of aggregation between crumb rubber and crushed sand increases the compressive strength will drop extremely. Second, aggregation replacement between crumb rubber and crushed sand lower than 30 % can show reduction in density at around 10% leading lower in its weight. Third, modulus of elasticity depends on the percentage of addition, the more rubber added to concrete the lesser it will be. In addition to that, the lower the toughness of concrete means the higher strength. Moreover; addition of rubber to concrete increases the toughness value of it (1).