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21.
The objective of this study was to investigate and evaluate the rheological and moisture susceptibility of the WMA mixtures
containing moist aggregates. The experimental design included the utilizations of two aggregate sources, two moisture, two
anti-stripping additives, and three WMA additives and control. Several properties of the binders and mixtures were obtained
including: viscosity, dynamic shear rheometer, beam bending rheometer of WMA binders, indirect tensile strength (ITS), tensile
strength ratio (TSR), and flow values. The experimental results indicate that the WMA additives can result in a slight decrease
in viscosity and an increase in failure temperature. In addition, the moisture susceptibility results illustrated that the
mixtures containing moist aggregates generally have similar ITS values to other mixtures regardless of HMA or WMA types. Moreover,
there were no significant differences in the wet ITS values of WMA mixture amongst four types of mixtures under identical
conditions (same moisture and lime contents) except for the mixtures containing liquid anti-stripping additive and Asphamin
additive. 相似文献
22.
Khaldoun M. Shatanawi Szabolcs BiroAndras Geiger Serji N. Amirkhanian 《Construction and Building Materials》2012,28(1):96-103
The use of furfural (C5H4O2) as an activation agent has been suggested as a method to improve the rheological properties of asphalt binders due to its compatibility with crumb rubber. This study uses five different crude sources and both ambient and cryogenic produced crumb rubber modifiers (CRM). The rheological properties for furfural activated and conventional CRM binders were evaluated using the dynamic shear rheometer (DSR) and the gel permeation chromatography (GPC). The results indicated that furfural activation has variable effects on the properties of the CRM binder. However, the most pronounced effect is shown in the storage stability improvement which will have an effect on the storage of CRM binder. Also, the activation caused a reduction in the ratio of the small molecular size distribution which is considered an improvement in the binder properties. 相似文献
23.
Soon-Jae Lee Hakseo Kim Serji N. Amirkhanian Kwang W. Kim 《Construction and Building Materials》2009,23(2):997-1004
This paper presents an experimental analysis of the relationship between molecular sizes of mixed rubberized binders (aged rubberized binders + virgin rubberized binders) and the engineering properties of recycled aged rubberized mixtures. Gel permeation chromatography (GPC) was utilized to characterize the molecular size change of rubberized binders depending on three aging levels and four long-term aged (LTA) binder percentages. Rubberized mixtures were artificially long-term aged in the laboratory, and the aged rubberized mixtures were recycled at 0%, 15%, 25%, and 35% (by weight of total mixture) using typical recycling guildelines. Samples of laboratory-prepared recycled aged rubberized mixtures were tested for indirect tensile strength (ITS) in dry and wet states, rutting resistance, resilient modulus, and ITS after long-term aging in the laboratory. In general, the results indicated that the compositional changes of mixed rubberized binders have good correlations with the engineering properties of recycled aged rubberized mixtures, except for the resilient modulus. 相似文献
24.
Soon-Jae Lee Serji N. Amirkhanian Nam-Won Park Kwang W. Kim 《Construction and Building Materials》2009,23(6):2371-2379
Reclaimed asphalt pavement (RAP) comprises one of the largest recycled materials, and warm mix asphalt (WMA) technologies become more commonly used due to their promising advantages in the United States and Europe. This paper addresses the laboratory investigation of performance properties of WMA binders containing aged binders. The recycled binders with the additives were produced using two (i.e., zeolite Aspha-min® and wax Sasobit®) of the available warm asphalt processes. The recycled WMA binders were artificially short-term and then long-term aged through the rolling thin film oven (RTFO) and pressure aging vessel (PAV) procedures. Superpave binder tests were carried out on the binders through the rotational viscometer, the dynamic shear rheometer (DSR), and the bending beam rheometer (BBR). In general, the results of this study indicated that (1) the additives and aged binders played an important role in determination of the binder properties; (2) the use of lower PG grade as a virgin binder (PG 58-28 in this study) was critical on offsetting the increase of binder stiffness caused by the addition of WMA additives and aged binders; and (3) even at the low recycling percentage of 15%, the lower PG grade was needed to get the results meeting current Superpave binder requirements. 相似文献
25.
Feipeng Xiao P.E. Wenbin Zhao Serji N. Amirkhanian 《Construction and Building Materials》2009,23(10):3144-3151
The long-term performance of pavement is associated with various factors such as pavement structure, materials, traffic loading, and environmental conditions. Improving the understanding of the fatigue behavior of the specific rubberized warm mix asphalt (WMA) is helpful in recycling the scrap tires and saving energy. This study explores the utilization of the conventional fatigue analysis approach in investigating the fatigue life of rubberized asphalt concrete mixtures containing the WMA additive. The fatigue beams were made with one rubber type (?40 mesh ambient crumb rubber), two aggregate sources, two WMA additives (Asphamin® and Sasobit®), and tested at 20 °C. A total of eight mixtures were performed and 29 fatigue beams were tested in this study. The test results indicated that the addition of crumb rubber and WMA additive not only reduced the mixing and compaction temperatures of rubberized asphalt mixtures offset by crumb rubber but also effectively extended the long-term performance of pavement when compared with conventional asphalt pavement. In addition, the exponential function forms are efficient in achieving the correlations between the dissipated energy and load cycle as well as mixture stiffness and load cycle. 相似文献