The increasing consumption of waste tire has generated many problems such as increasing landfill space, environmental pollution and causing health hazards. Parallel to this is the increasing of roads construction as a result of heavy traffic on roads. This study reviews to the use of crumb rubber (waste tires in powder form) in bitumen using the wet process. The study focuses on the crumb rubber as a replacement to the total weight of bitumen. The design or life span for all highways and urban roads is 10 – 20 years. Unfortunately, damages or distresses on pavements are still occurring before reaching the maximum period of the designed road serviceability. Among the major influencing factor that is contributing to this distress is the repeated heavy traffic loading on the road surfaces. Moreover, the use of waste crumb rubber in road construction as a pavement surface has a better skid resistance, fatigue crack resistance and increased rut resistance. The review includes physical tests that are used to determine the physical properties of bitumen and modified crumb rubber mix. The physical tests involve penetration test, softening point test and viscosity test. The second stage is rheological tests like rolling thin film oven test (RTFOT), pressure aging vessel (PAV) and dynamic shear rheometer (DSR) tests. The expectations from the study are to develop bitumen with waste crumb rubber that would minimize the costs of bitumen and providing better physical and rheological properties compared to the convention bitumen based on the tests that was conducted. Crumb rubber modifier as improved resistance to rutting due to high viscosity, Improved resistance to surface initiated, reduce fatigue/ reflection cracking, lower pavement maintenance costs, and saving in energy and natural resource.
Evaluation of mortars with combined use of fine recycled aggregates and waste crumb rubber
