Abstract
This paper presents the results of experimental investigation of flexible pavement dense-graded bituminous wearing course (BWC) and stone matrix asphalt (SMA) for performance and resistance to permanent deformation. Two mixtures of BWC were prepared using different aggregate gradations of crushed dolomite rocks with natural and crushed sands, and 60/70 grade unmodified bitumen. Two mixtures of SMA were prepared from crushed dolomite aggregates with crushed dust and polymer modified binder. Crumb rubber and reclaimed polyethylene were used as modifiers to improve the viscoelastic behavior and rheological properties of 60/70 grade bitumen. Laboratory prepared specimens evaluated using binder properties tests and mixture performance tests including draindown, loaded wheel, marshall, and indirect tensile strength (ITS), and ultrasonic. The results of conventional tests show that a mixture of BWC with crushed sand and SMA with crumb rubber have the highest stability and ITS, with greater reduction in rut depth than the other mixtures. Ultrasonic results show that a mixture of BWC with crushed sand and SMA with crumb rubber have higher elasticity value and failure stress and lower failure strain than the other mixtures. We conclude that variations occur because of changes of aggregate properties, packing of aggregate through the compaction, binder content, and type of modified binders. Ultrasonic wave propagation tests may also be used to evaluate pavement design and performance, as well as conventional tests.