Specification parameter for asphalt mixtures using frequency sweep data from the Superpave shear tester

2000 ◽  
Vol 1 (1-2) ◽  
pp. 75-96 ◽  
Author(s):  
Aroon Shenoy ◽  
Pedro Romero
Keyword(s):  
Asphalt Mixtures ◽  
Frequency Sweep ◽  
Shear Tester

Precision of Shear Tests in Evaluating Asphalt Mixtures

2003 ◽  
Vol 1832 (1) ◽  
pp. 155-160 ◽  
Author(s):  
R. Michael Anderson ◽  
Richard K. Steger ◽  
Gerald A. Huber ◽  
Pedro Romero
Keyword(s):  
Mechanical Properties ◽  
Hot Mix Asphalt ◽  
Shear Stiffness ◽  
Asphalt Mixtures ◽  
Shear Tests ◽  
Frequency Sweep ◽  
Constant Height ◽  
Repeated Load ◽  
Shear Tester ◽  
Highway Research

Various methods exist to measure the mechanical properties of hot-mix asphalt (HMA). To be useful such a test not only must measure a property that controls performance but also must be repeatable. The Strategic Highway Research Program developed tests with the Superpave® shear tester that have been shown to be related to HMA performance. To date, repeatability has not been quantified. The results of a repeatability study for the measurement of shear stiffness (frequency sweep) and of permanent shear strain (repeated-load, constant-height testing) are reported.

scholarly journals The Effect of Ageing on Chemical and Mechanical Properties of Asphalt Mortar

2018 ◽  
Vol 8 (11) ◽  
pp. 2231 ◽  
Author(s):  
Ruxin Jing ◽  
Xueyan Liu ◽  
Aikaterini Varveri ◽  
Athanasios Scarpas ◽  
Sandra Erkens
Keyword(s):  
Mechanical Properties ◽  
Asphalt Mixtures ◽  
Pavement Performance ◽  
Frequency Sweep ◽  
Carbonyl Index ◽  
Mineral Particles ◽  
Tension Tests ◽  
Ftir Spectrometry ◽  
Diffusion Paths ◽  
Asphalt Mortar

Asphalt mortar is a mixture of bitumen, filler, and sand. Mortar plays an important role in asphalt mixtures as it serves as the adhesive between the coarser aggregates. Due to the effect of bitumen ageing, the chemical and mechanical properties of asphalt mortar evolve with time. The mortar becomes more brittle and prone to cracking, thus leading to inferior pavement performance. In this study, Fourier transform infrared (FTIR) spectrometry was used to quantify changes in the chemical functional groups related to ageing and to calculate the carbonyl and sulfoxide indices. In addition, frequency sweep tests and uniaxial tension tests were performed by means of dynamic shear rheometer (DSR) tests to determine evolution of the stiffness and strength due to ageing. Two different oven ageing protocols were used to evaluate the effect of fine mineral particles on bitumen ageing. The protocols differed with respect to the order of ageing and mixing of the constituents. The results showed that both the chemical and mechanical properties of mortars significantly changed with ageing. Specifically, the carbonyl index, stiffness, and strength of the mortar increased. Under the same ageing conditions, a higher ageing level was observed for mortars produced by first mixing and then ageing compared to the mortars produced by mixing aged bitumen with filler and sand. This could be due to the presence of sand and filler particles, which resulted in an increased length of diffusion paths and consequently a slower ageing process.

Do Asphalt Mixtures Correlate Better with Mastics or Binders in Evaluating Permanent Deformation?

2003 ◽  
Vol 1829 (1) ◽  
pp. 16-25 ◽  
Author(s):  
Aroon Shenoy ◽  
Kevin Stuart ◽  
Walaa Mogawer
Keyword(s):  
Rheological Properties ◽  
Permanent Deformation ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Strong Interactions ◽  
Two Phase ◽  
Modified Asphalt ◽  
Asphalt Mastics ◽  
Polymer Modified Asphalt ◽  
Shear Tester

Researchers have often looked for relationships between mechanical properties of asphalt mixtures and rheological properties of binders when assessing the resistance of mixtures and binders to permanent deformation. When mixtures are subjected to deformation on application of a stress, aggregates act as load-bearing entities, and binders deform in response to applied stress. Intuitively, a correlation must exist between the properties of mixtures and binders. However, a good correlation usually is not observed. There could be a number of reasons for the observed poor correlations, including ( a) variability in the data or a possible change in the microstructure of two-phase, polymer-modified asphalt in the presence of aggregates, or ( b) strong interactions between the aggregate and the binder that, of course, are not reflected in the binder properties. In such cases, there are reasons to believe asphalt mastics might provide a better correlation because they would account for at least the physicochemical aspects of the aggregate–binder interaction. The present work compared asphalt mixture data initially with mastic data and then separately with binder data. The mastic and binder rheological data were generated with the same equipment under identical conditions of measurement to identify which one correlates better with the mixture data. A good correlation was obtained in only one case when Superpave® shear tester data for mixtures were compared with the dynamic shear rheometer data for binders. In all cases analyzed in this work, no correlation was found between the permanent deformation for mixtures and the rheological properties of the mastics.

Uniaxial Shear Tester – new test method to determine shear properties of asphalt mixtures

2016 ◽  
Vol 18 (sup1) ◽  
pp. 87-103 ◽  
Author(s):  
Josef Zak ◽  
Carl L. Monismith ◽  
Erdem Coleri ◽  
John T. Harvey
Keyword(s):  
Asphalt Mixtures ◽  
Test Method ◽  
Shear Properties ◽  
Shear Tester

Frequency sweep implementation of adaptive multi-level substructuring

1997 ◽  
Author(s):  
Jeffrey Bennighof ◽  
Matthew Kaplan ◽  
Jeffrey Bennighof ◽  
Matthew Kaplan
Keyword(s):  
Frequency Sweep ◽  
Multi Level

A Hybrid Model to Predict the Gyratory Compaction of Hot Mixed Asphalt

2019 ◽  
Author(s):  
Teng Man
Keyword(s):  
Hybrid Model ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Aggregate Size ◽  
Asphalt Mixtures ◽  
Compaction Process ◽  
Particle Rearrangement ◽  
Compaction Behavior ◽  
Grain Size Distributions ◽  
Gyratory Compaction

The compaction of asphalt mixture is crucial to the mechanical properties and the maintenance of the pavement. However, the mix design, which based on the compaction properties, remains largely on empirical data. We found difficulties to relate the aggregate size distribution and the asphalt binder properties to the compaction behavior in both the field and laboratory compaction of asphalt mixtures. In this paper, we would like to propose a simple hybrid model to predict the compaction of asphalt mixtures. In this model, we divided the compaction process into two mechanisms: (i) visco-plastic deformation of an ordered thickly-coated granular assembly, and (ii) the transition from an ordered system to a disordered system due to particle rearrangement. This model could take into account both the viscous properties of the asphalt binder and grain size distributions of the aggregates. Additionally, we suggest to use the discrete element method to understand the particle rearrangement during the compaction process. This model is calibrated based on the SuperPave gyratory compaction tests in the pavement lab. In the end, we compared the model results to experimental data to show that this model prediction had a good agreement with the experiments, thus, had great potentials to be implemented to improve the design of asphalt mixtures.

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