The Experts below are selected from a list of 4839 Experts worldwide ranked by ideXlab platform
Bjorn Birgisson - One of the best experts on this subject based on the ideXlab platform.
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low temperature cracking performance of wma with the use of the superpave Indirect Tensile Test
Construction and Building Materials, 2012Co-Authors: Prabir Kumar Das, Yuksel Tasdemir, Bjorn BirgissonAbstract:Abstract Low temperature cracking of wax modified bitumen and asphalt mixtures were studied using the Dynamic Shear Rheometer (DSR), Bending Beam Rheometer (BBR), Superpave IDT and Thermal Stress Restrained Specimens Test (TSRST). Two types of commercial waxes (FT-paraffin and Asphaltan-B) were added to 70/100 penetration grade bitumen. Hot Mix Asphalt (HMA) fracture mechanics was used to determine fracture parameters. Master curves obtained from DSR and BBR Test results showed stiffening effect due to wax additive at low temperature. The analysis of covariance was performed using a General Linear Model (GLM) on the Superpave IDT Test results for Energy Ratio (ER) by using SPSS (Statistical Program for Social Sciences). Statistical analysis of Superpave IDT results showed a minor negative effect of wax modification at lower temperatures. Statistical analysis also showed that fracture parameters are highly temperature dependent and the two types of aggregate used did not play any significant role in low temperature cracking performance. Results obtained from TSRST Tests indicate wax modification has a minor negative effect in low temperature cracking performance of asphalt mixtures.
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multilayer boundary element method for evaluating top down cracking in hot mix asphalt pavements
Transportation Research Record, 2004Co-Authors: Boonchai Sangpetngam, Bjorn Birgisson, Reynaldo RoqueAbstract:Cracking in hot-mix asphalt (HMA) pavements is a major mode of premature failure. Recent work at the University of Florida has led to the development of a new viscoelastic fracture mechanics-based crackgrowth law called the HMA fracture mechanics law, which is capable of fully describing both initiation and propagation of cracks in asphalt mixtures. The successful simulations of crack growth for generalized pavement conditions depend largely on how well the state of stress can be predicted in and around existing cracks in pavements. Previous work has focused on the adaptation of a displacement-discontinuity boundary-element method for predicting stresses in the Superpave® Indirect Tensile Test (IDT), which then were subsequently used to predict the crack initiation and crack growth in simulated IDT Tests that used HMA fracture mechanics. The previous displacement-discontinuity boundary-element formulation is here extended into layered materials. Homogeneous layers are stitched together numerically in "wel...
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guidelines for use of modifiers in superpave mixtures executive summary and volume 1 of 3 volumes evaluation of sbs modifier
2004Co-Authors: R Roque, Bjorn Birgisson, M Tia, Beomjun Kim, Z CuiAbstract:A laboratory investigation was conducted to evaluate the effects of Styrene Butadiene Styrene (SBS) polymer modification on the cracking resistance and healing characteristics of Superpave mixtures. Asphalt mixtures with low and high design asphalt contents using unmodified and SBS modified asphalt cements were produced in the laboratory. Tests performed with the Superpave Indirect Tensile Test (IDT) included resilient modulus Tests, creep Tests, repeated load fracture Tests, healing Tests, strength Tests at two loading rates, as well as longer-term creep Tests to failure. The Test results showed that the benefit of SBS modifiers to mixture cracking resistance appeared to be derived primarily from a reduced rate of micro-damage accumulation. The reduced rate of damage accumulation was reflected in a lower m-value without a reduction in fracture limit. However, SBS modifier does not appear to influence healing or aging of asphalt mixture. Therefore, it was shown that the benefits of the SBS modifier were clearly identified by using the Hot Mix Asphalt (HMA) fracture model, which accounts for the combined effects of m-value and fracture energy limit on cracking resistance. It was also determined that the residual dissipated energy as determined from Superpave IDT strength Tests appears to be uniquely associated with the presence and benefit of SBS modification, and may provide a quick way to make relative comparisons of cracking performance. Longer-term creep Tests showed that time to crack initiation appeared to provide another parameter uniquely related to the effects of SBS modification. Cost analyses indicate that the construction cost of asphalt concrete (AC) layer would be reduced by using SBS modifier. Consequently, the use of SBS modified mixtures was clearly justified. In conclusion, the key to characterizing the effects of SBS modifier on the cracking resistance of asphalt mixture is in the evaluation of the combined effects of creep and failure limits.
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development of efficient crack growth simulator based on hot mix asphalt fracture mechanics
Transportation Research Record, 2003Co-Authors: Boonchai Sangpetngam, Bjorn Birgisson, Reynaldo RoqueAbstract:It has long been accepted that cracking of hot-mix asphalt (HMA) pavements is a major mode of premature failure. Many state departments of transportation have verified that pavement cracking occurred not only in fatigue cracking in which a crack initiates from the bottom of the asphalt layer but also in other modes such as low-temperature cracking and the more recently identified top-down cracking. Recent work at the University of Florida has led to the development of a crack growth law based on viscoelastic fracture mechanics that is capable of fully describing both initiation and propagation of cracks in asphalt mixtures. The model requires the determination of only four fundamental mixture parameters, which can be obtained from less than 1 h of Testing using the Superpave® Indirect Tensile Test (IDT). These parameters can account for microdamage, crack propagation, and healing for stated loading conditions, temperatures, and rest periods. The generalization of the HMA crack growth law needed for its su...
Reynaldo Roque - One of the best experts on this subject based on the ideXlab platform.
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multilayer boundary element method for evaluating top down cracking in hot mix asphalt pavements
Transportation Research Record, 2004Co-Authors: Boonchai Sangpetngam, Bjorn Birgisson, Reynaldo RoqueAbstract:Cracking in hot-mix asphalt (HMA) pavements is a major mode of premature failure. Recent work at the University of Florida has led to the development of a new viscoelastic fracture mechanics-based crackgrowth law called the HMA fracture mechanics law, which is capable of fully describing both initiation and propagation of cracks in asphalt mixtures. The successful simulations of crack growth for generalized pavement conditions depend largely on how well the state of stress can be predicted in and around existing cracks in pavements. Previous work has focused on the adaptation of a displacement-discontinuity boundary-element method for predicting stresses in the Superpave® Indirect Tensile Test (IDT), which then were subsequently used to predict the crack initiation and crack growth in simulated IDT Tests that used HMA fracture mechanics. The previous displacement-discontinuity boundary-element formulation is here extended into layered materials. Homogeneous layers are stitched together numerically in "wel...
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development of efficient crack growth simulator based on hot mix asphalt fracture mechanics
Transportation Research Record, 2003Co-Authors: Boonchai Sangpetngam, Bjorn Birgisson, Reynaldo RoqueAbstract:It has long been accepted that cracking of hot-mix asphalt (HMA) pavements is a major mode of premature failure. Many state departments of transportation have verified that pavement cracking occurred not only in fatigue cracking in which a crack initiates from the bottom of the asphalt layer but also in other modes such as low-temperature cracking and the more recently identified top-down cracking. Recent work at the University of Florida has led to the development of a crack growth law based on viscoelastic fracture mechanics that is capable of fully describing both initiation and propagation of cracks in asphalt mixtures. The model requires the determination of only four fundamental mixture parameters, which can be obtained from less than 1 h of Testing using the Superpave® Indirect Tensile Test (IDT). These parameters can account for microdamage, crack propagation, and healing for stated loading conditions, temperatures, and rest periods. The generalization of the HMA crack growth law needed for its su...
Boonchai Sangpetngam - One of the best experts on this subject based on the ideXlab platform.
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multilayer boundary element method for evaluating top down cracking in hot mix asphalt pavements
Transportation Research Record, 2004Co-Authors: Boonchai Sangpetngam, Bjorn Birgisson, Reynaldo RoqueAbstract:Cracking in hot-mix asphalt (HMA) pavements is a major mode of premature failure. Recent work at the University of Florida has led to the development of a new viscoelastic fracture mechanics-based crackgrowth law called the HMA fracture mechanics law, which is capable of fully describing both initiation and propagation of cracks in asphalt mixtures. The successful simulations of crack growth for generalized pavement conditions depend largely on how well the state of stress can be predicted in and around existing cracks in pavements. Previous work has focused on the adaptation of a displacement-discontinuity boundary-element method for predicting stresses in the Superpave® Indirect Tensile Test (IDT), which then were subsequently used to predict the crack initiation and crack growth in simulated IDT Tests that used HMA fracture mechanics. The previous displacement-discontinuity boundary-element formulation is here extended into layered materials. Homogeneous layers are stitched together numerically in "wel...
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development of efficient crack growth simulator based on hot mix asphalt fracture mechanics
Transportation Research Record, 2003Co-Authors: Boonchai Sangpetngam, Bjorn Birgisson, Reynaldo RoqueAbstract:It has long been accepted that cracking of hot-mix asphalt (HMA) pavements is a major mode of premature failure. Many state departments of transportation have verified that pavement cracking occurred not only in fatigue cracking in which a crack initiates from the bottom of the asphalt layer but also in other modes such as low-temperature cracking and the more recently identified top-down cracking. Recent work at the University of Florida has led to the development of a crack growth law based on viscoelastic fracture mechanics that is capable of fully describing both initiation and propagation of cracks in asphalt mixtures. The model requires the determination of only four fundamental mixture parameters, which can be obtained from less than 1 h of Testing using the Superpave® Indirect Tensile Test (IDT). These parameters can account for microdamage, crack propagation, and healing for stated loading conditions, temperatures, and rest periods. The generalization of the HMA crack growth law needed for its su...
Baoshan Huang - One of the best experts on this subject based on the ideXlab platform.
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evaluation of moisture damage in hot mix asphalt using simple performance and superpave Indirect Tensile Tests
Construction and Building Materials, 2008Co-Authors: Xingwei Chen, Baoshan HuangAbstract:Abstract Moisture damage has been one of the major concerns for hot mix asphalt (HMA) pavements. In the present study, efforts have been made to evaluate the moisture damage of a dense-graded surface HMA mixture using simple performance Test (SPT) and Superpave™ Indirect Tensile Test (IDT). Coarse gravels at three different angularity levels (100, 50 and 0% fractured surface counts) were used to produce mixtures with similar aggregate gradations. Asphalt binders (PG 64-22) with and without amine-based antistrip additive (ASA) were used to make mixtures for laboratory moisture damage evaluations. Specimens were conditioned by four different methods: (1) one cycle of freeze-thaw (F-T), (2) two cycles of F-T, (3) 500 cycles of pore pressure pulses with Moisture Induced Stress Tester (MIST), and (4) 1000 cycles with MIST. The dynamic modulus, Superpave IDT creep, resilient modulus and strength Tests were performed on conditioned and unconditioned specimens. The results from this study indicated that the SPT dynamic modulus Test and the Superpave IDT with F-T or MIST conditionings were effective to characterize lab-measured moisture susceptibility of HMA mixtures. Increasing F-T or MIST cycles would increase moisture damage in HMA mixtures. Amine-based antistrip additive was effective to decrease the moisture damage in HMA mixtures. Increasing coarse aggregate angularity (CAA) levels could increase dynamic modulus; however, it seemed that CAA had no significant effects on the lab-measured moisture resistance of HMA mixtures.
Prabir Kumar Das - One of the best experts on this subject based on the ideXlab platform.
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low temperature cracking performance of wma with the use of the superpave Indirect Tensile Test
Construction and Building Materials, 2012Co-Authors: Prabir Kumar Das, Yuksel Tasdemir, Bjorn BirgissonAbstract:Abstract Low temperature cracking of wax modified bitumen and asphalt mixtures were studied using the Dynamic Shear Rheometer (DSR), Bending Beam Rheometer (BBR), Superpave IDT and Thermal Stress Restrained Specimens Test (TSRST). Two types of commercial waxes (FT-paraffin and Asphaltan-B) were added to 70/100 penetration grade bitumen. Hot Mix Asphalt (HMA) fracture mechanics was used to determine fracture parameters. Master curves obtained from DSR and BBR Test results showed stiffening effect due to wax additive at low temperature. The analysis of covariance was performed using a General Linear Model (GLM) on the Superpave IDT Test results for Energy Ratio (ER) by using SPSS (Statistical Program for Social Sciences). Statistical analysis of Superpave IDT results showed a minor negative effect of wax modification at lower temperatures. Statistical analysis also showed that fracture parameters are highly temperature dependent and the two types of aggregate used did not play any significant role in low temperature cracking performance. Results obtained from TSRST Tests indicate wax modification has a minor negative effect in low temperature cracking performance of asphalt mixtures.
