S.P. Wu

Research of Bituminous MortarFatigue Test Method Based on Dynamic Shear Rheometer

This paper presents a new test method that allows fatigue characterization on bituminous mortar by means of dynamic shear rheometer (DSR). The studied mortar is composed of bitumen, filler and fine sand at a mass ratio of 0.34:0.30:0.36. Dynamic shear rheometer instruments are widely used for bitumen testing by using parallel plate geometry. However, the parallel plate geometry is not suitable for mortar testing due to the fact that the mortar contains fine sand. To take good advantage of DSR instruments, mortar specimen and clamp system were specially designed so that mortar testing can be performed by using DSR instruments under parallel plate control mode. Due to the complex specimen geometry, finite element simulations were performed to translate the torque and deformation that the specimen was subjected into the real mortar stress and strain. An intensive experimental program indicated that the developed test method was capable to capture the shear fatigue behaviour of mortar at meso-scale by using DSR instruments.

Using Activated Carbon to Reduce the Volatile Organic Compounds from Bituminous Materials

AbstractThe objective of this research is to characterize the reduction of volatile organic compounds (VOCs) from bituminous materials resulted from activated carbon. A gas chromatography-mass spec...

Low Temperature Properties of Waste Edible Vegetable Oil Rejuvenated Asphalt Binder with Recycled Tire Rubber

Waste edible vegetable oil (WEVO) can restore the physical and rheological properties of aged asphalt by replenishing decreased aromatics. However, low-temperature properties of WEVO rejuvenated asphalt (WRA) still require further improvement. The purpose of this research was to evaluate the effect of recycled tire rubber (RTR) on low-temperature properties of WRA. Penetration, softening point, ductility, and viscosity of WRA with various RTR contents were first studied. Then rheological properties including complex modulus, phase angle, fatigue parameter, creep recovery, and stress relaxation were well investigated. Meanwhile, the compatibility between WRA and RTR was characterized by storage stability test. Experimental results indicated that adding RTR can improve the low-temperature properties of WRA, and 2.0 wt. % of aged asphalt is the optimal RTR content in this research. Moreover, the compatibility between WRA and RTR meet the Chinese standard JTG E20 T0661-2011.

Identification of Rejuvenators on Porous-Asphalt Concrete Using Optical Microscopy and Nanoindentation Technology

AbstractApplication of rejuvenation products on porous asphalt pavements as a preventive maintenance technology has been investigated recently by the Dutch Ministry of Transportation. Traditionally, the main contribution of rejuvenators to porous asphalt pavements is considered as restoring its flexibility. Whether this really is the case is investigated in the research reported in this paper. For this purpose, identification of rejuvenators is done using optical microscopy and nanoindentation technology. Visual inspection from optical microscopy shows that all applied rejuvenation products, except for bitumen emulsion BE-1, provide an additional bituminous binder film to the mortar and also fill microcracks. The decrease of indentation modulus of the mortar shows that BE-1 and BE-2 can penetrate into the mortar and improve its flexibility.

Adhesion Properties of Tar-Containing Antiskid Surface Layers on Runways in Airfield

Tar-containing antiskid surface layers are currently used on runways in airfields. They have good adhesion properties and excellent fuel resistance, which make them outstanding compared to other surface layers with bitumen as binder. However, tar-containing products have a high Polycyclic Aromatic Hydrocarbons (PAHs) content. They are toxic and not environmental-friendly. Tar-containing products are not allowed in the Netherlands since 20 years ago, with one temporary exception for antiskid surfaces on runways in airfields. After 2010, it will not be allowed to apply such antiskid layers anymore. For this reason, alternatives to tar containing binders for antiskid runways are strongly required. Before looking into alternatives, the properties of tar-containing antiskid surface layer need to be evaluated and benchmarks should be developed. This paper focuses on the mechanical properties of tar-containing antiskid surface layers. A special Leutner shear test and an advanced pull test were designed to test the shear and tensile strength in the interface between the tar containing antiskid layer and the asphalt mixture layer below. Test results are reported in this paper.