scholarly journals Characterization of the Adhesive and Cohesive Moisture Damage for Asphalt Concrete

2019 ◽  
Author(s):  
Mona Nobakht
Keyword(s):  
Asphalt Concrete ◽  
Asphalt Binder ◽  
Damage Model ◽  
Moisture Diffusion ◽  
Adhesive Bond ◽  
Moisture Damage ◽  
Asphalt Mixtures ◽  
Asphalt Pavements ◽  
Dynamic Modulus Test ◽  
Early Degradation

Durability of asphalt concrete is significantly influenced by moisture damage, resulting in early degradation of asphalt pavements. There are several tests and conditioning methods adopted by agencies and researchers to identify the susceptibility of asphalt mixtures to the moisture damage. However, there is a need to develop predictive models that account for the impacts of moisture on fundamental mechanistic properties of asphalt concrete. In this regard, the focus of this paper is to develop an adhesive and a cohesive moisture damage model that enable the prediction of the amount of induced damages due to the moisture diffusion in the asphalt concrete. The models are developed based on intermolecular bond energy/force, and the mechanisms of cohesive and adhesive failures. They assume water vapor diffusion as the dominant moisture transport mode in asphalt pavements. The models are calibrated and validated by conducting dynamic modulus test on Fine Asphalt Matrix mixtures as well as Bitumen Bond Strength test on the adhesive bond between aggregate and asphalt binder. The results of validation process show the competence of the proposed models in predicting the adhesive and cohesive moisture damage of asphalt mixtures.

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.

Laboratory Evaluation of Mixture Type on Highly Modified Asphalt Mixtures in Virginia

2018 ◽  
Vol 2672 (28) ◽  
pp. 59-68
Author(s):  
Benjamin F. Bowers
Keyword(s):  
Asphalt Binder ◽  
Aggregate Size ◽  
Asphalt Mixtures ◽  
Laboratory Evaluation ◽  
Maximum Aggregate Size ◽  
Air Voids ◽  
Modified Asphalt ◽  
Modified Asphalt Binder ◽  
Dynamic Modulus Test ◽  
Scb Specimen

The work presented attempts to address reflective cracking of asphalt-surfaced pavements through binder modification with a highly polymer (HP)-modified asphalt binder. Nine asphalt mixtures ranging from fine dense-graded mixtures to stone matrix asphalt (SMA) mixtures were investigated with conventional polymer modified binders and HP binder. The dynamic modulus test, overlay test (OT), and semi-circular bend (SCB) test were used to evaluate the mixtures. In the cracking tests, HP mixtures outperformed the conventionally modified control mixtures for the same mixture type. For HP mixtures, in general, SMA mixtures performed better in the cracking test than dense-graded mixtures. One of the dense-graded mixtures having larger nominal maximum aggregate size (NMAS) performed better than the mixture with a smaller NMAS, whereas the other having a larger NMAS was not significantly different in crack testing. Further, a discussion on the calculation of bulk specific gravity and percent air voids in a cut OT and SCB specimen using saturated surface dry or vacuum sealing methods is presented.

scholarly journals Effect of Nanoclay Particles on the Performance of High-Density Polyethylene-Modified Asphalt Concrete Mixture

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 434
Author(s):  
Ghada S. Moussa ◽  
Ashraf Abdel-Raheem ◽  
Talaat Abdel-Wahed
Keyword(s):  
Asphalt Concrete ◽  
High Density Polyethylene ◽  
Storage Stability ◽  
Chemical Change ◽  
Asphalt Binder ◽  
Moisture Damage ◽  
High Density ◽  
Damage Resistance ◽  
Negative Impacts ◽  
Roadway Construction

Utilizing polymers for asphalt concrete (AC) mixture modification has many drawbacks that hinder its wide implementations for roadway construction. Recently, research on employing complementary materials, such as nanomaterials, to balance negative impacts of polymers while enhancing the AC mixture’s performance has received great attention. This study aimed to investigate the effect of incorporating nanoclay (NC) particles on the performance of a high-density polyethylene (HDPE)-modified AC mixture. A 60/70 asphalt binder was first modified with HDPE, and then NC particles were gradually added at a concentration of 1–4% by weight of the asphalt binder. The binders’ physical characteristics, storage stability, and chemical change were scrutinized. AC mixture performance, including pseudo-stiffness, moisture damage resistance, stripping susceptibility, and rutting tendency, was investigated. A statistical analysis on the experimental results was conducted using Kruskal–Wallis and Dunn tests. Test results showed that employing NC/HDPE significantly increased penetration index and thereby enhanced binder temperature sensitivity. Moreover, it prevented oxidation action and separation and, therefore, enhanced binder storage stability. Furthermore, incorporating NC amplified pseudo-stiffness and significantly improved resistance against moisture damage and stripping of HDPE-modified mixtures. Moreover, it improved both elastic (recoverable) and plastic (unrecoverable) deformations of mixtures. The most satisfactory results were attained when incorporating 3% of NC.

Soft Asphalt Pavement – Solution for Low-Volume Roads in Changing Climate and Economy

2014 ◽  
Vol 934 ◽  
pp. 47-52 ◽  
Author(s):  
Audrius Vaitkus ◽  
Viktoras Vorobjovas ◽  
Donatas Čygas ◽  
Algis Pakalnis
Keyword(s):  
Asphalt Concrete ◽  
Laboratory Tests ◽  
Applied Research ◽  
Asphalt Pavement ◽  
Cost Effective ◽  
Asphalt Mixtures ◽  
Alternative Solution ◽  
Asphalt Pavements ◽  
Low Volume Roads ◽  
Low Volume

In Lithuania, it has always has been an important issue to find durable and cost-effective solutions for paving low-volume roads. The conventional asphalt concrete structures were built using paving grade bitumen with the penetration of 70/100 or 100/150 over the recent 20 years. The performance of those pavements was satisfactory. As an alternative solution, the use of soft asphalt pavements was proposed. This technology is widely used in Nordic countries. But in Lithuania it has never been applied. Research on the designed soft asphalt mixtures was carried out and the trial on-site sections were constructed. The results of laboratory tests and on-site research were positive and promising. Based on that, the technology could be considered as successfully implemented and good quality was achieved.

Low Temperature Cracking Evaluation of Asphalt Rubber Mixtures Using Semi-Circular Bending Test

2011 ◽  
Vol 243-249 ◽  
pp. 4201-4206 ◽  
Author(s):  
Jing Hui Liu
Keyword(s):  
Low Temperature ◽  
Asphalt Concrete ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Asphalt Pavements ◽  
Dry Process ◽  
Wet Process ◽  
Asphalt Rubber ◽  
Scb Test ◽  
Low Temperature Cracking

Low temperature cracking is the main distress in asphalt pavements in winter. As asphalt rubber course is increasing, there is no standard method to characterize the resistance to cracking of asphalt rubber mixtures. This paper investigates the use of a Semi Circular Bend (SCB) test as a candidate for a low-temperature cracking specification. Based on the SCB test, this paper presents the findings of a laboratory study that aimed to evaluate the effects of recycled tire rubber on the Low temperature cracking properties of asphalt mixtures. Three mix types, a conventional hot-mix asphalt concrete, a dry process rubber modified asphalt concrete, and a wet process asphalt-rubber asphalt concrete, were included in the investigation. It is found that the asphalt mixtures produced by the wet process showed much better low temperature crack resistance, the binder effect modified by rubber was significant.

Effects of Conductive Fillers on the Dynamic Response and Fatigue life of Conductive Asphalt Concrete

2007 ◽  
Vol 348-349 ◽  
pp. 145-148 ◽  
Author(s):  
Shao Peng Wu ◽  
Bo Li ◽  
Jian Qiu ◽  
Ning Li
Keyword(s):  
Fatigue Life ◽  
Asphalt Concrete ◽  
Dynamic Modulus ◽  
Load Cycle ◽  
Initial Crack ◽  
Asphalt Pavements ◽  
Negative Effects ◽  
Cycle Times ◽  
Dynamic Modulus Test ◽  
Conductive Fillers

It is currently interesting to use thermal or electrical conductive asphalt concrete for snow-melting and maintenance of asphalt pavements in winter. The addition of conductive fillers may have negative effects on the mechanical properties of asphalt concrete. The performance of conductive asphalt concrete is greatly affected by the initial crack and its propagation. Laboratory tests for neat and conductive asphalt concrete include Dynamic Modulus Test (DMT) and Indirect Tensile Fatigue Test (ITFT). DMT tests indicates that the value of dynamic modulus of asphalt concrete decreases with the increasing graphite content. It means that the conductive asphalt concrete achieves lower stiffness. It can be concluded from ITFT tests that the fatigue life (load cycle times) of conductive asphalt concrete is more than neat ones when stress level is under 1.0 MPa. Meanwhile higher fatigue resistance of conductive asphalt concrete is observed when carbon fibers (2 weight % of total aggregate) were added together with 22% graphite, especially at low stress levels.

Effect of Latex to Minimize the Use of Asphalt in Asphalt Concrete Wearing Course

2019 ◽  
Vol 961 ◽  
pp. 39-44
Author(s):  
Henri Siswanto
Keyword(s):  
Asphalt Concrete ◽  
Asphalt Pavement ◽  
Asphalt Binder ◽  
Renewable Resource ◽  
Binder Content ◽  
Asphalt Mixtures ◽  
Total Weight ◽  
Mineral Aggregate ◽  
Wet Process

One aspect that needs to be considered in the application of asphalt pavement is the fact that asphalt is a non-renewable resource which requires constant maintenance throughout its lifetime. Thus, developing a mix with asphalt contents reduced to the minimum is a challenge in and of itself. Latex, in this case, would seem to be potentially viable additives. The aim of this research is to investigate the effects of using latex as an additive to minimize the use of asphalt in asphalt concrete wearing courses (ACWC). Four varying amounts of latex were mixed with asphalt at 0%, 2%, 4%, and 6% of the total weight of an asphalt binder. A wet process was then employed to blend the mixtures together. Afterward, the latex-asphalt mixtures were added to an aggregate to form various mixtures ranging from 5% to 7% of the aggregate and the incremental weight of 0.5% of the latex-asphalt ACWC. For each latex-asphalt-aggregate mixes, the optimum binder content was determined based on stability, flow, Marshall quotient, voids in the mineral aggregate (VMA), voids in the mixture (VIM) and voids filled by the binder (VFB). The results of this experiment indicated that the addition of latex reduces the need for asphalt contents.

Moisture Damage Evaluation of Asphalt Mixtures by Considering Both Moisture Diffusion and Repeated-Load Conditions

2003 ◽  
Vol 1832 (1) ◽  
pp. 42-49 ◽  
Author(s):  
DingXin Cheng ◽  
Dallas N. Little ◽  
Robert L. Lytton ◽  
James C. Holste
Keyword(s):  
Surface Energy ◽  
Diffusion Model ◽  
Gas Adsorption ◽  
Moisture Diffusion ◽  
Moisture Damage ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Adsorption Model ◽  
Damage Models ◽  
Adhesion Failure

Two moisture damage models based on major moisture failure mechanisms are proposed. The adhesion failure model was developed to analyze the adhesive fracture between asphalt and aggregate in the presence of water. Cohesive and adhesive fractures in an asphalt-aggregate system are directly related to the surface energy characteristics of asphalt and aggregate. The surface energy of adhesion with or without the presence of water can be calculated from the surface energies of asphalt and aggregate. A moisture diffusion model was developed based on the one-dimensional consolidation of soil and a gas adsorption model. The moisture diffusion model was used to obtain the moisture diffusion characteristics of asphalt binders, including the amount of moisture that can permeate a binder and the diffusivity of the binder. The amount of moisture that permeates a binder is identified as a key factor in the moisture damage. Finally, mechanics-based experiments conducted on asphalt mixtures validated the results from the adhesion failure and diffusion models.

Evaluation of rheological behavior and performance to permanent deformation of nanomodified asphalt mixtures with carbon nanotubes

2016 ◽  
Vol 43 (5) ◽  
pp. 472-479 ◽  
Author(s):  
João Victor Staub de Melo ◽  
Glicério Trichês
Keyword(s):  
Carbon Nanotubes ◽  
Permanent Deformation ◽  
Asphalt Binder ◽  
Asphalt Mixtures ◽  
Asphalt Pavements ◽  
Accelerated Degradation ◽  
Wheel Tracking Test ◽  
And Performance ◽  
Wheel Tracking ◽  
Reference Mixture

Rutting is one of the most important issues associated with asphalt pavements. This defect leads to the accelerated degradation of the pavement and considerably reduces the level of road safety. This paper reports on the results obtained in the optimization of nanocomposite asphalt containing carbon nanotubes (CNTs) with regard to the resistance to permanent deformation. Nanocomposite asphalts were prepared with the addition of different proportions of CNTs. Based on a study on the empirical and rheological properties of the nanocomposites developed, optimization of the CNT content incorporated into the conventional asphalt binder was carried out. Then two asphalt mixtures were investigated, a reference mixture and a nanomodified mixture with CNTs (optimal content). The rheological evaluations were carried out on four-point fatigue equipment and the resistance to permanent deformation was tested in a traffic simulator (wheel tracking test). The results demonstrate the efficient contribution of the nanocomposite to the resistance to permanent deformation.

scholarly journals Laboratory and Statistical Analysis of the Fatigue Response of Self-Healing Asphalt Mixtures Containing Metal By-Products

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 385
Author(s):  
Marta Vila-Cortavitarte ◽  
Daniel Jato-Espino ◽  
Daniel Castro-Fresno ◽  
Miguel Á. Calzada-Pérez
Keyword(s):  
Asphalt Concrete ◽  
Asphalt Pavement ◽  
Fatigue Behavior ◽  
Asphalt Mixtures ◽  
Environmental Benefits ◽  
Asphalt Pavements ◽  
Similar Response ◽  
Self Healing ◽  
By Products ◽  
Industrial Sand

Fatigue is one of the main forms of deterioration in asphalt mixtures, endangering their service life due to the progressive appearance and expansion of cracks. A sustainable approach to increase the lifetime of asphalt pavement has been found in self-healing technology, especially if boosted with metal by-products due to their economic and environmental interest. Under these circumstances, this research addressed the fatigue behavior of self-healing asphalt mixtures including industrial sand blasting by-products obtained from sieving and aspiration processes. Hence, a uniaxial fatigue test was carried out to determine whether these experimental mixtures can provide a similar response to that of a reference asphalt concrete (AC-16). This analysis was undertaken with the support of descriptive and inferential statistics, whose application proved the absence of significant differences in the fatigue performance of self-healing experimental mixtures with respect to conventional asphalt concrete. These results suggest that designing self-healing mixtures with metal by-products is a sustainable approach to increase the lifetime of asphalt pavements, while contributing to the circular economy through diverse economic and environmental benefits.

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