Peng Li

Emulsified asphalt treated base (EATB) is a cold mixture of emulsified asphalt (emulsion) and granular material. The resilient modulus (M_R) of EATB is an essential parameter for both material evaluation and pavement design. Triaxial tests can be used to measure M_R and capture its nonlinear property affected by the stress state. However, such complicated test is not available for most routine practices. In this study, triaxial tests were conducted to measure M_R of EATB at different stress states. The effects of influencing factors, such as residual binder contents, aggregate property, dry density and temperature, on resilient property of EATB were also investigated. The nonlinear predictive models were further developed based on the modified universal soil model and all factors and interactions among them were incorporated.

In the summer of 2008, a field trial project using Sasobit-modified warm-mix asphalt (WMA) was established in Alaska, which was Alaska’s first experience with a WMA technology. Previous studies conducted by writers identified a number of engineering benefits of Sasobit-modified WMAs over conventional hot-mix asphalt (HMA). This paper presents a further assessment focusing on low temperature performance of both Sasobit-modified WMA binders and mixes. A series of binder tests including bending beam rheometer (BBR), direct tension test (DTT), and asphalt binder cracking device (ABCD) tests were conducted. Indirect tension tests (IDT) of mixtures along with a thermal cracking analysis were performed to obtain a more definitive answer regarding the WMA application for cold-weather conditions. Results showed a decrease of tensile strength for both WMA binders and mixtures at low temperatures, and the cracking temperatures of both WMA binders and mixtures increased with the increase of Sasobit content. However, ...

A number of completed or ongoing studies on different aspects of warm-mix asphalt (WMA) have being conducted in the United States, indicating pavement professionals’ strong interest in exploring the application of this innovative technology. In the summer of 2008, a field trial project using Sasobit-modified WMA was established in the southeastern region of Alaska, which was Alaska’s first experience with a WMA technology. In line with this field experimental feature project, this paper presents a systematic laboratory study of both Sasobit-modified WMA binders and mixes. Engineering properties of Sasobit-modified WMA binders and mixes were experimentally evaluated, and the effects of Sasobit addition on the WMA’s performance in terms of low temperature behavior, rutting resistance, and moisture susceptibility were investigated. Research results identified a number of engineering benefits of Sasobit-modified WMAs over conventional HMA. Sasobit-modified WMAs reduced mixing and compaction temperatures, impr...

In many areas of Alaska, clean, durable aggregates normally utilized for base course either require long hauls from outside, or are difficult to obtain within the project limits. Asphalt treatment is the most commonly used type of stabilization for the available lower quality materials to increase their strength thus extending their life and saving money to the state in the long run. This paper evaluates the effectiveness of different asphalt stabilization methods including hot asphalt treatment, foamed asphalt treatment, and emulsion asphalt treatment. A case study of pavement design using the Alaska Flexible Pavement Design (AKFPD) program was conducted to incorporate the effect of resilient behavior of different asphalt treated base layers on the pavement performance (resistances to rutting and cracking).