Modifying the Sand Concrete with Recycled Tyre Polymer Fiber to Increase the Crack Resistance of Building Structures

Abstract

Recently, the use of recycled tyre polymer fiber derived from waste tires as a concrete reinforcement has received a great deal of attention. The recycled tyre polymer fiber is a promising additive to concrete for building materials which require resistance against cracking. In this work, the effect of treated and untreated fiber on the properties of sand concrete was studied. It was shown that recycled tyre polymer fiber consists mainly of different fractions of crumb rubber, fiber, and metal fiber. The main polymer components in the fiber are polyamide and polyester threads of 6.5 mm length (l) and 0.05 mm diameter (d); the ratio l/d = 150; and the average fiber density is 0.923 g/cm3. It was established that the addition of untreated recycled tyre polymer fiber in the amounts of 11 and 19 kg/m3 into sand concrete leads to a decrease in compressive and flexural strengths by 15% and 21%, respectively. The reinforcement of concrete with the treated fiber in the amounts of 5 and 10 kg/m3 increases the flexural strength by 14% and 23.4%, respectively. The prismatic strength of the concrete which contents 5 and 10 kg/m3 of the treated polymer fiber was lower than that of ordinary concrete by 10.8% and 4.6%, respectively. The obtained results showed that the use of recycled tyre polymer fiber increases the crack resistance of concrete. The recycled tyre polymer fiber can be used as a cost-effective alternative to other types of low-modulus fibers to produce durable building materials.