The National Center for Asphalt Technology (NCAT) completed a roundrobin study in March to determine the accuracy and precision of the NCAT asphalt content tester. The Center has conducted research since 1990 to develop this test method for determining asphalt content of hot mix asphalt (HMA) mixtures by ignition (See the fall, 1994, issue of Asphalt Technology News). In the ignition method, a ...

In recent years, there has been a huge demand for innovative methods to upcycle waste materials. This study aims explore and evaluate the effect of using low-density polyethylene (w-LDPE), collected from plastic bags domestic purposes, on mechanical properties dense Thin Asphalt Overlay (TAO). Waste materials have deemed appropriate in development asphalt pavement mixtures, due expected enhance...

This work aims to improve the rutting and fatigue cracking resistance of asphalt binders using selected nanoor micro-sized materials and to shed light on the microstructure changes induced by such modification to asphalt binders. The four modifiers (Nanomer I.44P, carbon microfiber, non-modified nanoclay and polymer modified nanoclay) were added into the control asphalt binder (PG 58-34). The S...

This paper characterizes the effects of artificial short term aging in the laboratory on the rheological properties of virgin 80/100 penetration grade asphalt binder. After several years in service, asphalt mixture started to deteriorate due to aging. Aging is a complex physico-chemical phenomenon that influences asphalt binder rheological properties causing a deterioration in asphalt mixture p...

The incremental health risk for workers of the road-paving sector using rubberized asphalt was assessed based on the outcome of monitoring campaigns carried out during paving operations where both rubberized and standard asphalt were used. The exposure of workers to Polycyclic Aromatic Hydrocarbons (PAHs) released in the asphalt fumes were measured by means of personal samplers and dermal sampl...

Standard asphalt mixtures for road infrastructures consist of natural aggregate and bitumen. A number of research efforts have successfully investigated the possibility of replacing the conventional aggregate skeleton with industrial by-products such as slag originating from steel production process. However, little is known on the effect of steel slag on the mixtures functional performance and...

Reflective cracking is a common distress of semi-rigid base asphalt pavements and overlay pavement projects. An rubber stress-absorbing membrane interlayer (AR-SAMI) prepared by waste tires an effective engineering solution for treating reflective cracking. This method can also reduce black pollution. However, there no unified test index crack resistance evaluation. In this work, AR-SAMIs with ...

This study presents micromechanical finite-element FE and discrete-element DE models for the prediction of viscoelastic creep stiffness of asphalt mixture. Asphalt mixture is composed of graded aggregates bound with mastic asphalt mixed with fines and fine aggregates and air voids. The two-dimensional 2D microstructure of asphalt mixture was obtained by optically scanning the smoothly sawn surf...

Road distress results in high maintenance costs. However, increased understandings of asphalt behaviour and properties coupled with technological developments have allowed paving technologists to examine the benefits of introducing additives and modifiers. As a result, polymers have become extremely popular as modifiers to improve the performance of the asphalt mix. This study investigates the ...

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