scholarly journals Granular-slurry rheology and asphalt compaction

2021 ◽  
Vol 249 ◽  
pp. 09010
Author(s):  
Teng Man ◽  
Kimberly Hill
Keyword(s):  
Interstitial Fluid ◽  
Asphalt Binder ◽  
Asphalt Mixtures ◽  
Dem Simulation ◽  
Fine Aggregates ◽  
Efficiency And Effectiveness ◽  
Slurry Rheology ◽  
Modelling Effort ◽  
Shed Light ◽  
Compaction Behaviour

Hot mixed asphalt (HMA) is a mixture of particles (coarse and fine aggregates) and interstitial fluid (asphalt binder) designed to compact and harden for long-lasting roads. In this study, we implement a two-scale approach to capture the compaction behaviour of hot asphalt mixtures using both a granular-slurry rheology (GSR) at a smaller scale and a discrete element method (DEM) simulation at the scale of a compactor. We show that this modelling effort captures the compaction of HMA with different binder viscosities modified by adding graphene nano-platelets (GNP). This research has the capacity to shed light on how the properties of mixture components can influence compaction efficiency and effectiveness.

scholarly journals Rheological and Interaction Analysis of Asphalt Binder, Mastic and Mortar

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 128 ◽  
Author(s):  
Meng Chen ◽  
Barugahare Javilla ◽  
Wei Hong ◽  
Changluan Pan ◽  
Martin Riara ◽  
...  
Keyword(s):  
Phase Change ◽  
Interaction Analysis ◽  
Asphalt Binder ◽  
Asphalt Mixtures ◽  
Physical Interaction ◽  
Fine Aggregate ◽  
Mineral Filler ◽  
Asphalt Mastic ◽  
Fine Aggregates ◽  
Asphalt Mortar

This paper investigated the rheological properties of asphalt binder, asphalt mastic and asphalt mortar and the interaction between asphalt binder, mineral filler and fine aggregates. Asphalt binder, mastic and mortar can be regarded as the binding phase at different scales in asphalt concrete. Asphalt mastic is a blend of asphalt binder and mineral filler smaller than 0.075 mm while asphalt mortar consists of asphalt binder, mineral filler and fine aggregate smaller than 2.36 mm. The material compositions of mastic and mortar were determined from the commonly used asphalt mixtures. Dynamic shear rheometer was used to conduct rheological analysis on asphalt binder, mastic and mortar. The obtained test data on complex modulus and phase angle were used for the construction of rheological master curves and the investigation of asphalt-filler/aggregate interaction. Test results indicated a modulus increase of three- to five-fold with the addition of filler and a further increase of one to two orders of magnitude with cumulative addition of fine aggregates into asphalt binder. Fine aggregates resulted in a phase change for mortar at high temperatures and low frequencies. The filler had stronger physical interaction than fine aggregate with an interaction parameter of 1.8–2.8 and 1.15–1.35 respectively. Specific area could enhance asphalt-filler interaction. The mastic and mortar modulus can be well predicted based on asphalt binder modulus by using particle filling effect. Asphalt mortar had a significant modulus reinforcement and phase change and thus could be the closest subscale in terms of performance to that of asphalt mixtures. It could be a vital scale that bridges the gap between asphalt binder and asphalt mixtures in multiscale performance analysis.

scholarly journals Kinerja Marshall Immersion pada Campuran Asphalt Concrete Wearing Course (AC-WC) dengan Penambahan Cangkang Sawit sebagai Substitusi Agregat Halus

2018 ◽  
Vol 15 (2) ◽  
pp. 99-105
Author(s):  
Mukhlis Mukhlis ◽  
Lusyana Lusyana ◽  
Enita Suardi ◽  
Fauna Adibroto
Keyword(s):  
Asphalt Concrete ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Natural Rock ◽  
Fine Aggregates ◽  
Asphalt Content ◽  
Volumetric Characteristics ◽  
Substitute Materials

Asphalt concrete wearing courses (AC-WC) are asphalt mixtures which consist of coarse and fine aggregates plus fillers which have a continuous gradation with asphalt binder. In general, the aggregates in the AC WC mixtures consist of natural rock materials which are broken down and in certain areas the availability is limited so it must be imported from other regions. This resulted in relatively high prices from the asphalt mixture. This can be anticipated by looking for alternative aggregate substitute materials, one alternative is to use palm oil shells. In this test, palm shells were used as a substitute for fine aggregates with variations in percentage of palm shells, namely 0%, 5%, 10%, 15%, 20%, 25%, the tests were carried out namely the testing of volumetric characteristics, Marshall characteristics, determination of optimum asphalt content and Marshall immersion. From the results of the study obtained the value of Marshall Immersion decreases as the percentage of palm shells increases in the mixture.

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.

Determining Optimum Carbon Nanotubes Content for Asphalt Mixture in Road Pavements

2021 ◽  
Vol 1023 ◽  
pp. 121-126
Author(s):  
Van Bach Le ◽  
Van Phuc Le
Keyword(s):  
Carbon Nanotubes ◽  
Asphalt Pavement ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Construction Cost ◽  
Asphalt Mixtures ◽  
Static Modulus ◽  
Pavement Construction ◽  
Modified Binder ◽  
Marshall Stability

Although small amount of binder in asphalt concrete mixture may commonly range from 3.5 to 5.5% of total mixture as per many international specifications, it has a significant impact on the total cost of pavement construction. Therefore, this paper investigated the effects of five carbon nanotubes contents of 0.05%, 0.1%, 0.15%, 0.2%, 0.25% by asphalt weight as an additive material for binder on performance characteristics of asphalt mixtures. Performance properties of CNTs modified asphalt mixtures were investigated through the Marshall stability (MS) test, indirect tensile (IDT) test, static modulus (SM) test, wheel tracking (WT) test. The results indicated that asphalt mixtures with CNT modified binder can improve both the rutting performance, IDT strength and marshall stability of tested asphalt mixtures significantly at higher percentages of carbon nanotubes. However, the issue that should be considered is the construction cost of asphalt pavement. Based on the asphalt pavement structural analysis and construction cost, it can be concluded that an optimum CNT content of 0.1% by asphalt weight may be used as additive for asphalt binder in asphalt mixtures.

scholarly journals Assessments on the Performance of Asphalt Mixtures Prepared with Adhesion Promoters

2019 ◽  
Vol 8 (3S3) ◽  
pp. 332-339
Keyword(s):  
Mechanical Performance ◽  
Water Immersion ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Adhesion Promoters ◽  
Modified Asphalt ◽  
Service Characteristics ◽  
Bonding Properties ◽  
Mechanical Performances

Asphalt pavement is typically susceptible to moisture damage. However, it could be improved with the incorporation of additives or modifiers through binder modifications. The objective of the study is to assess the effect of adhesion promoters, namely PBL and M5000, onto the Hot Mix Asphalt (HMA). The performance of asphalt mixture has been assessed in terms of the service characteristics, the bonding properties, and mechanical performances. The service characteristics were assessed through the Workability Index (WI) and Compaction Energy Index (CEI) to evaluate the ease of asphalt mixture during the mixing and compaction stage. The bonding properties of the modified asphalt mixtures were determined using the boiling water test and static water immersion test to signify the degree of coating after undergoing specific conditioning period and temperature. The mechanical performances of the modified asphalt mixture were evaluated via Marshall stability, semi-circular bending, and modified Lottman tests. All specimens were prepared by incorporating adhesion promoters at the dosage rates of 0.5% and 1.0% by weight of asphalt binder. From the investigation, the bonding properties significantly improved for the modified asphalt mixture compared to the control mixture. The WI of the modified asphalt mixture increased while the CEI decreased in comparison to the control specimen. This implies the workability of modified asphalt mixture is better and requires less energy to be compacted. Modified asphalt mixture generally had better mechanical performance. Therefore, it can be deduced that the asphalt mixture with adhesion promoters have better overall performance than the control mixture.

Effect of Coarse Aggregate Morphology on the Resilient Modulus of Hot-Mix Asphalt

2005 ◽  
Vol 1929 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Tongyan Pan ◽  
Erol Tutumluer ◽  
Samuel H. Carpenter
Keyword(s):  
Surface Texture ◽  
Coarse Aggregate ◽  
Resilient Modulus ◽  
Asphalt Binder ◽  
Aggregate Size ◽  
Asphalt Mixtures ◽  
Maximum Aggregate Size ◽  
Asphalt Mixes ◽  
Aggregate Morphology ◽  
The Relationship

The resilient modulus measured in the indirect tensile mode according to ASTM D 4123 reflects effectively the elastic properties of asphalt mixtures under repeated load. The coarse aggregate morphology quantified by angularity and surface texture properties affects resilient modulus of asphalt mixes; however, the relationship is not yet well understood because of the lack of quantitative measurement of coarse aggregate morphology. This paper presents findings of a laboratory study aimed at investigating the effects of the material properties of the major component on the resilient modulus of asphalt mixes, with the coarse aggregate morphology considered as the principal factor. With modulus tests performed at a temperature of 25°C, using coarse aggregates with more irregular morphologies substantially improved the resilient modulus of asphalt mixtures. An imaging-based angularity index was found to be more closely related to the resilient modulus than an imaging-based surface texture index, as indicated by a higher value of the correlation coefficient. The stiffness of the asphalt binder also had a strong influence on modulus. When the resilient modulus data were grouped on the basis of binder stiffnesses, the agreement between the coarse aggregate morphology and the resilient modulus was significantly improved in each group. Although the changes in aggregate gradation did not significantly affect the relationship between the coarse aggregate morphology and the resilient modulus, decreasing the nominal maximum aggregate size from 19 mm to 9.5 mm indicated an increasing positive influence of aggregate morphology on the resilient modulus of asphalt mixes.

Effectiveness of Loaded Wheel Tracking Test to Ascertain Moisture Susceptibility of Asphalt Mixtures

2021 ◽  
pp. 036119812110363
Author(s):  
Moses Akentuna ◽  
Louay N. Mohammad ◽  
Sanchit Sachdeva ◽  
Samuel B. Cooper ◽  
Samuel B. Cooper
Keyword(s):  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Moisture Damage ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Creep Recovery ◽  
Moisture Susceptibility ◽  
Freeze Thaw ◽  
Wheel Tracking ◽  
Mixture Samples

Moisture damage of asphalt mixtures is a major distress affecting the durability of asphalt pavements. The loaded wheel tracking (LWT) test is gaining popularity in determining moisture damage because of its ability to relate laboratory performance to field performance. However, the accuracy of LWT’s “pass/fail” criteria for screening mixtures is limited. The objective of this study was to evaluate the capability of the LWT test to identify moisture susceptibility of asphalt mixtures with different moisture conditioning protocols. Seven 12.5 mm asphalt mixtures with two asphalt binder types (unmodified PG 67-22 and modified PG 70-22), and three aggregate types (limestone, crushed gravel, and a semi-crushed gravel) were utilized. Asphalt binder and mixture samples were subjected to five conditioning levels, namely, a control; single freeze–thaw-; triple freeze–thaw-; MiST 3500 cycles; and MiST 7000 cycles. Frequency sweep at multiple temperatures and frequencies, and multiple stress creep recovery tests were performed to evaluate asphalt binders. LWT test was used to evaluate the asphalt mixture samples. Freeze–thaw and MiST conditioning resulted in an increase in stiffness in the asphalt binders as compared with the control. Further, freeze–thaw and MiST conditioning resulted in an increase in rut depth compared with the control asphalt mixture. The conditioning protocols evaluated were effective in exposing moisture-sensitive mixtures, which initially showed compliance with Louisiana asphalt mixture design specifications.

Effect of polyphosphoric acid on fracture properties of asphalt binder and asphalt mixtures

2021 ◽  
Vol 310 ◽  
pp. 125240
Author(s):  
Mohammad Ali Ziari ◽  
Pouria Hajikarimi ◽  
Afarin Kheirati Kazerooni ◽  
Fereidoon Moghadas Nejad ◽  
Elham H. Fini
Keyword(s):  
Polyphosphoric Acid ◽  
Asphalt Binder ◽  
Asphalt Mixtures ◽  
Fracture Properties

scholarly journals Linking the Effect of Aggregate Interaction to the Compaction Theory for Asphalt Mixtures Using Image Processing

2018 ◽  
Vol 8 (11) ◽  
pp. 2045 ◽  
Author(s):  
Kyoungchul Kim ◽  
Myungook Kang
Keyword(s):  
Image Processing ◽  
High Temperature ◽  
Asphalt Binder ◽  
Asphalt Mixtures ◽  
Energy Index ◽  
Optimum Temperature ◽  
Frictional Behavior ◽  
Viscosity Effect ◽  
Frictional Interaction ◽  
Compaction Energy

This study presents a modified compaction concept of asphalt mixtures based on aggregate frictional behavior using self-developed image processing for measuring the aggregate orientation. The compaction energy index was introduced to evaluate the aggregate orientation on different compaction temperatures. For the better rearrangement of aggregates, there was an optimum temperature at which a preferred orientation exists, providing lower compaction efforts. An excessively high temperature reduced the asphalt contents for lubrication and caused additional aggregate friction to require higher compaction efforts. This phenomenon can be found in the changes of the volume of the effective asphalt binder (Veac) and the absorbed asphalt binder (Pba). The mixture produced higher Veac, at which an optimum compaction temperature required lower compaction energy. Despite being higher than the optimum temperature for the PG62-28 mixture, the Veac decreased by 0.4%. An increase of 0.35% in the Pba was inferred to flow into the aggregates. Clearly, a reduction of lubricant in the mixture caused a higher frictional interaction between aggregates. Changes in the Veac and the Pba can eliminate the viscosity effect for the rearrangement of aggregates. Based on the aggregate orientation and change in mixture volumetrics, the aggregate interaction effect was introduced to the Mohr–Coulomb compaction theory to explain the additional friction.

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