EFFECT OF PARTIAL REPLACEMENT OF FINE AGGREGATES WITH NON-TREATED TYRE DERIVED AGGREGATE FOR COMMON CONCRETE APPLICATIONS

摘要

The disposal of end-of-life car and truck tyres is a significant environmental and logistical issue, with large volumes being sent to landfill sites. This investigation focuses on investigating the effect of using Tyre Derived Aggregate (TDA) as a substitute for traditional mineral aggregates in common concrete without having to pre-treat the crumbs and compromising significantly on the mechanical properties. Six mixes were produced, 0, 2, 4, 6, 8 and 10 TDA substitution for sand by volume using a common 50 MPa concrete formulation. Fresh, mechanical, physical and durability parameters as well as fire resistance of concrete with/without TDA have been investigated. The results show that the workability is not affected by including TDA. The compressive/tensile strengths are slightly reduced in this range of the ratios of substitution and the 50 MPa target was always reached. A reduction in capillary absorption coefficient and an increase in resistance to water penetration was observed with the increase of TDA content in the mix. After being exposed to fire, samples with TDA contents 6-10 showed only a reduction of 27 in compressive strength compared to 44 reduction of strength for samples having no TDA. Overall, the test results provide evidence that incorporating TDA alters the characteristics of a concrete mix, increasing its performance in durability without compromising much on concrete characteristics. The recommended optimum dosage of untreated TDA is up to 6 in order to have minimal impact on mechanical and durability aspects.