Ongoing projects:

·           Investigation of Improvement of Sulfur Extended Asphalt

·           High Strength Bases: Portland Cement and Bituminous Stabilization.

Investigation of Improvement of Sulfur Extended Asphalt

(Principal Investigator:Dr. Amit Bhasin, UT-Austin-USA)

The crude oil produced and processed in KSA results in significant amount of sulfur as a by-product.  Sulfur, when used as partial replacement for asphalt binder, can significantly improve the stiffness and deformation resistance of asphalt mixtures, which is a major source of pavement distress due to the local climatic conditions in KSA.  Therefore, by careful incorporation of sulfur as a partial replacement of asphalt binder, KSA can (i) consume a major crude oil by-product, (ii) reduce the use of more expensive asphalt binder, (iii) enhance the durability of the pavement, and (iv) promote environment friendly technologies. While the benefits of sulfur as a partial replacement of binder are clear, it cannot be indiscriminately replaced for asphalt in all asphalt mixtures. 

This study employs the latest tools developed by the research institutions over the last five years to evaluate material durability to address the research goals.  The findings from this research can provide guidelines for optimal use of sulfur in asphalt mixes without compromising its durability and long-term performance. If properly implemented, careful use of sulfur can improve the deformation resistance of asphalt pavements, particularly in a climate like that of KSA. Typically, sulfur is less expensive than asphalt binder that is suitable for KSA climate. Partial substitution of binder with sulfur has the potential to reduce the cost of pavement construction and maintenance.

High Strength Bases: Portland cement and Bituminous Stabilization" (Principal Investigator: Dr.Erol Tutumluer, TEST, USA)

Soil stabilization has been widely used worldwide and is a proven technology. This project is intended to identify soils and locally available aggregates for constructing high strength base courses within the Kingdom of Saudi Arabia (KSA) that will benefit from stabilization with bitumen or Portland cement stabilization and to provide a protocol for laboratory characterization, design, and construction of these stabilized, high strength bases.

The nature of the desert soils in KSA, especially in the eastern provinces, makes them amenable to treatment and stabilization with Portland cement and with bitumen in the form of emulsion or foamed asphalt. However, the high salt and sulphur contents interfere with Portland cement stabilization in a deleterious manner. Therefore, this project will develop protocols for stabilizer selection, mixture design, and performance modeling as well as construction protocols to optimize the use of Portland cement and bitumen to successfully treat the native soils and aggregate sources within KSA.  The project outcome will bring sustainable practices to road construction and rehabilitation projects, provide safe, environmentally friendly and long lasting roads to public / freight, and ultimately enable growth and economic development in the region.

Completed Projects:

The chair has successfully completed following projects:

·      Benchmarking Pavement Practices for KSA Roadways

·      Life-Cycle Assessment of Using Sulfur-Extended Asphalt  in Pavements

Benchmarking Pavement Practices for KSA Roadways

(Principal Investigator: Dr. Ghassan Chehab, American University of Beirut, Lebanon)

The main objective of this project was to develop benchmarks to be used by highway agencies and stakeholders in the Kingdom of Saudi Arabia (KSA), particularly by the Ministry of Transport (MOT) and the Ministry of Municipalities and Rural Affairs (MOMRA), for the assessment of pavement practices and policies of the roadway sector. Practices of interest include evaluation, planning, design, construction, specifications and management of pavement-related aspects of the existing roadway network. The work was conducted over the course of two years, starting March of year 2015.

Benchmarking pavement practices in KSA was conducted against the Emirates of Dubai and Abu Dhabi in the United Arab Emirates, the State of Qatar, and the Sultanate of Oman. The United States of America was selected as the international benchmark country, being one of the leading countries in both research and practice in various areas of pavement engineering, and having the largest road network in the world.

Results from the benchmarking study can ultimately aid highway agencies and stakeholders in performing an internal evaluation of their current state-of-practice. The study can be used as a solid reference for future industry and research projects in KSA. It can aid in identifying areas of possible improvement and needs for modification of existing practices, launching of new initiatives, creation of programs, and adoption of new technologies.

Life-Cycle Assessment of Using Sulfur-Extended Asphalt  in Pavements

(Principal Investigator: Dr. Yanfeng Ouyang,TEST, Inc,USA)

With the excess of by-product sulfur in many oil and gas producing countries, engineers must find new markets that can successfully use this by-product. In the recent decades, interest in sulfur-extended asphalt (SEA) has emerged. In order for the KSA to move forward with the use of SEA, a comprehensive environmental assessment conducted to better evaluate the sustainability of using sulfur in roadway construction compared to other conventional or modified AC pavements. To ensure that a systematic and accurate approach is used, a life-cycle assessment (LCA) methodology has been applied to various product systems, including pavements, to capture environmental impacts at each stage of a product’s life-cycle.

The study modeled the processes and technologies used in the KSA by collecting questionnaire responses distributed to various contractors, plant facilities, and Ministry of Transportation (MOT) representations in the KSA. The main contribution of this study was an LCA report detailing the potential environmental impacts of using SEA as well as a LCA software (SEL²ECT v1.0) developed as part of this project. The software allows users to calculate the life-cycle environmental impacts of various types of pavement projects, including SEA and conventional AC pavements. This software can be implemented by various stakeholders and decision makers in the KSA to analyze future pavement projects to obtain an indication of the environmental impacts of various pavement designs, including those involving SEA.

Future project:

Influence of asphalt binder properties on the performance of asphalts in Saudi Arabia (Principal Investigator: Dr. Ghassan Chehab, American University of Beirut, Lebanon)

The behavior of asphalt concrete as a material, and the subsequent performance of a flexible pavement, is influenced by the properties of the constitutive materials of the asphalt mix: the aggregates, asphalt binder, and air voids, as well as their interaction. Therefore, an understanding of the behavior of the binder in general, and under local conditions in particular, is required to develop adequate binder specifications that help avoid the development of distresses such as rutting, cracking, raveling, bleeding, and shoving that deteriorate the pavement surface and structure and significantly reduce its service life.  This study is expected to conduct in collaboration with Saudi Aramco, KFU and AUB.