Performance Of Asphalt Mixes Research Articles

Effect of Filler Types on Marshall Stability and Retained Strength of Asphalt Concrete

Mineral fillers play a critical role in the performance of asphalt mixes. Several types of mineral fillers are used worldwide. In Kuwait, two main mineral fillers are used; ordinary Portland cement (OPC) and pulverized limestone. This paper presents the results of a study undertaken to compare the effects of using the two types of mineral fillers on the strength of asphalt mixes as measured by Marshall stability and retained strength. Three filler contents were considered in the study; they were: 4, 5, and 6% by weight of aggregate. The analysis showed that both filler types have similar effect on Marshall stability. However, using OPC resulted in higher values of retained strength.

Laboratory Characterization of Asphalt Mixes of SPS-1 Sections on US281

ABSTRACT This paper presents the results of comprehensive laboratory characterization of the premature rutted specific pavement studies-1 (SPS-1) sections on US281 in south Texas. It was soon found that it was the undocumented change in aggregate type from the limestone to gravel screenings and too much asphalt binder that caused the deeply premature rutting. As a follow-up study, the extensive laboratory tests on those cores were further conducted to establish which of the available laboratory test procedures could match the observed field performance. It was determined that both uniaxial Repeated Simple Shear Test at Constant Height and repeated load test could correctly rank the rutting performance of asphalt mixes. For the wheel tracking tests, the Asphalt Pavement Analyzer performed better than Hamburg Wheel Tracking Test, but both failed to differentiate between the bad and good mixes in this case. The moduli at high temperature, including axial dynamic modulus, axial resilient modulus, and shear resilient modulus, could screen out the bad mixes. However, except for shear resilient modulus, others failed to further differentiate the performance of mixes in each good or bad group.

Measurement of Aggregate Texture and its Influence on Hot Mix Asphalt (HMA) Permanent Deformation

Aggregate shape has a significant effect on the performance of asphalt mixes. Designing well-performing asphalt pavements requires developing methods to quantify rapidly and accurately the different aggregate shape properties, and most importantly, relate these properties to performance. Aggregate texture has been identified in several studies to be the shape property that has the most significant influence on asphalt mix performance. This study presents a new procedure for measuring aggregate texture using image analysis techniques. The main advantages of this new procedure are the ability to capture the different sizes of texture elements, to separate the true texture from the color variations on the aggregate surface, and to characterize both fine and coarse aggregates. The procedure is used to measure texture for a wide range of fine and coarse aggregates, and the results are compared with the laboratory performance of asphalt mixes. The analysis shows that the procedure yields detailed information on aggregate texture in a short time. The texture measurements have very good correlation with the resistance of asphalt mixes to permanent deformation measured in the laboratory using different wheel tracking devices.

Laboratory Characterization of Asphalt Mixes of SPS-1 Sections on US281

ABSTRACT This paper presents the results of comprehensive laboratory characterization of the premature rutted specific pavement studies-1 (SPS-1) sections on US281 in south Texas. It was soon found that it was the undocumented change in aggregate type from the limestone to gravel screenings and too much asphalt binder that caused the deeply premature rutting. As a follow-up study, the extensive laboratory tests on those cores were further conducted to establish which of the available laboratory test procedures could match the observed field performance. It was determined that both uniaxial Repeated Simple Shear Test at Constant Height and repeated load test could correctly rank the rutting performance of asphalt mixes. For the wheel tracking tests, the Asphalt Pavement Analyzer performed better than Hamburg Wheel Tracking Test, but both failed to differentiate between the bad and good mixes in this case. The moduli at high temperature, including axial dynamic modulus, axial resilient modulus, and shear resilient modulus, could screen out the bad mixes. However, except for shear resilient modulus, others failed to further differentiate the performance of mixes in each good or bad group.

Asphalt Mix Evaluations: Case Study at San Francisco International Airport

A forensic study of asphalt mix performance at the San Francisco International Airport (SFIA) using the simple shear test developed by the Strategic Highway Research Program is described. The study examined taxi ways subjected to stationary and slow movements of heavy aircraft wheel loads and covered a period of about 2.5 years. The results of the study indicate the need to modify (or change) current FAA criteria for mix design of asphalt mixes for heavy-duty airfield pavements, particularly for taxi ways used for takeoff operations and subjected to stop-and-go operations of heavy aircraft like the Boeing 747-400. Information presented suggests that the simple shear test conducted in repeated loading while the height of the specimen is maintained constant (RSST-CH) can be used as a replacement for the current FAA mix evaluation procedure using the Marshall test. Mix design criteria are presented and are based on satisfactory performance of a high-stability mix introduced at SFIA for taxiways.