Developing Technologies and Procedures to Reduce Tracking and Achieve Uniform and Accurate Tack Coat Application

2020 ◽  
Vol 2674 (6) ◽  
pp. 326-338
Author(s):  
Erdem Coleri ◽  
Richard Villarreal ◽  
Blaine M. Wruck
Keyword(s):  
Fatigue Cracking ◽  
Application Rate ◽  
Asphalt Pavements ◽  
Stress And Strain ◽  
Tack Coat ◽  
Pavement Structure ◽  
Pavement Layers ◽  
Major Factors ◽  
Interlayer Bonding ◽  
Time Point

The tack coat bond is known to affect the longevity of asphalt pavements. Proper interlayer bonding prevents successive pavement layers from acting independently of one another and creating non-uniform stress and strain profiles in the pavement structure. Poor bonding between pavement layers can result in various pavement failures such as slippage cracking, debonding, and early fatigue cracking, all of which contribute to a reduced pavement fatigue life. Tack coat application rate and uniformity (that can be achieved by uniform tack coat application and by avoiding/minimizing tracking) are two major factors that control the performance of the tack coat bonding and longevity of the pavement structure. In this study, a wireless scale system (OreTackRate) that can be controlled from a tablet computer was developed to measure tack coat application rate accuracy and uniformity. The developed wireless scale system was recommended to be implemented during construction to validate application rate accuracy and uniformity. In addition, a distributor truck certification process was developed and presented in this study. The developed scale system can also be used to determine whether the applied tack coat is cured at any time point during construction. Residual tack coat application rate can also be measured using OreTackRate during construction. Implementation of all these tests, procedures, and technologies is expected to improve the tack coat uniformity during construction and improve the overall longevity of the pavement structure.

scholarly journals The Classification of Mechanical Models of Road Pavements

2018 ◽  
Vol 64 (4) ◽  
pp. 155-170
Author(s):  
R. Nagórski
Keyword(s):  
Heavy Traffic ◽  
Mechanistic Modelling ◽  
Physical Criterion ◽  
Structural Criterion ◽  
Mechanical Models ◽  
Pavement Structure ◽  
Pavement Layers ◽  
Interlayer Bonding

AbstractA review of mechanical models of road pavements in the form of a proposal of classification of these models is presented. It is assumed an autonomy of the following elements of pavement model: the models of structural layers, the subgrade model, the interlayer bonding models, including bonding of pavement structure with its subgrade, the models of external impacts on pavement layers, including load of heavy traffic, the models of pavement environment impacts on structural layers’ borders (lateral) and subgrade borders (including the lower one) – according to the selected criteria such as structural criterion, material criterion (physical criterion), dimension criterion and model scope (purpose) criterion − in the frame of assumptions of the classical Newtonian deterministic mechanics. The presented attempt to classify mechanical models of road pavements supports to orientate the roadmen community within a scope of the mechanistic modelling of these structures.

Factors Related to the Appearance of Transverse Bumps in Asphalt Overlays Placed over Crack Sealant

2017 ◽  
Vol 2630 (1) ◽  
pp. 128-133
Author(s):  
Scott Shuler
Keyword(s):  
Asphalt Mixture ◽  
Application Rate ◽  
Asphalt Pavements ◽  
Transverse Cracks ◽  
Water Intrusion ◽  
Asphalt Overlay ◽  
Bow Wave ◽  
Tack Coat ◽  
Asphalt Overlays ◽  
Pavement Foundation

Crack sealants often are used as a preservation tool in asphalt pavements. These sealants are placed in cracks to prevent water intrusion into the pavement foundation. Through the reduction of water intrusion, the strength of foundation layers is maintained, and acceptable pavement performance is extended. However, when a hot-mix asphalt overlay is placed on top of a pavement that contains crack sealants, a bump and additional transverse cracks sometimes occur in the new overlay asphalt. These bumps and sometimes transverse cracks are initiated during breakdown rolling and become progressively more severe on further compaction. This paper presents the results of a 5-year study designed to identify factors that related to the appearance of these bumps and consequent cracks. The results of the study indicated that vibratory breakdown rolling, pavement gradient, sealant geometry, tack coat application rate, and tack coat adhesivity were factors that contributed most to the occurrence of bumps and transverse cracks during asphalt overlay construction over crack sealants. Observations suggested that transverse bumps and consequent cracks occurred in proportion to the size of the bow wave of asphalt concrete present immediately in front of the breakdown roller. The increase in the bow-wave size depended on asphalt mixture properties, breakdown roller size, speed, vibration characteristics, and pavement gradient. Three pavement test sections also indicated that the tack coat application rate had an effect on reduction in the appearance of transverse bumps.

Technological Study on Interlayer Bonding of Double-Layer Porous Asphalt Pavement

2013 ◽  
Vol 405-408 ◽  
pp. 1725-1732 ◽  
Author(s):  
Guo Qi Tang ◽  
Dong Wei Cao ◽  
Ke Zhong ◽  
Xiao Qiang Yang
Keyword(s):  
Double Layer ◽  
Asphalt Pavement ◽  
Layer By Layer ◽  
Simulation Experiments ◽  
Porous Asphalt ◽  
One Step ◽  
Bonding Technology ◽  
Pavement Structure ◽  
Technological Study ◽  
Interlayer Bonding

The interlayer bonding of double-layer porous asphalt pavement will show more variations with different construction technologies, such as one-step molding by double-layer (hot on hot) paver, or paving layer by layer (hot on cold) with or without tack coat, and the variations will definitely have influences on pavement structure. Different interlayer technologies are studied in this paper on three levels including simulation experiments on specimen by indoor preparation, calculation of pavement mechanics, and construction of testing road, so that optimal interlayer bonding technology for double-layer porous asphalt pavement is discussed in combination with its effect on permeability.

Effect of freeze-thaw cycles on fatigue cracking and rutting of asphalt pavements

2019 ◽  
pp. 199-205
Author(s):  
A. Abdelaziz ◽  
C.H. Ho ◽  
J. Shan ◽  
A. Almonnieay
Keyword(s):  
Fatigue Cracking ◽  
Asphalt Pavements ◽  
Freeze Thaw

scholarly journals Long-Term Performance of Pavement Structures with Cold In-Place Recycled Base Course

2021 ◽  
Vol 16 (2) ◽  
pp. 48-65
Author(s):  
Audrius Vaitkus ◽  
Judita Gražulytė ◽  
Andrius Baltrušaitis ◽  
Jurgita Židanavičiūtė ◽  
Donatas Čygas
Keyword(s):  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Asphalt Pavements ◽  
Recycled Asphalt ◽  
Binding Agents ◽  
Pavement Structure ◽  
Pavement Structures ◽  
Base Course ◽  
Surface Distress ◽  
Foamed Bitumen

Properly designed and maintained asphalt pavements operate for ten to twenty-five years and have to be rehabilitated after that period. Cold in-place recycling has priority over all other rehabilitation methods since it is done without preheating and transportation of reclaimed asphalt pavement. Multiple researches on the performance of cold recycled mixtures have been done; however, it is unclear how the entire pavement structure (cold recycled asphalt pavement overlaid with asphalt mixture) performs depending on binding agents. The main objective of this research was to evaluate the performance of cold in-place recycled asphalt pavements considering binding agents (foamed bitumen in combination with cement or only cement) and figure out which binder leads to the best pavement performance. Three road sections rehabilitated in 2000, 2003, and 2005 were analysed. The performance of the entire pavement structure was evaluated in terms of the International Roughness Index, rut depth, and pavement surface distress in 2013 and 2017.

scholarly journals Maintenance Techniques for Cracks in Asphalt Layers

2021 ◽  
pp. 25-37
Author(s):  
M. S. Eisa ◽  
F. S. Abdelhaleem ◽  
V. A. Khater
Keyword(s):  
Failure Load ◽  
Asphalt Pavements ◽  
Water Intrusion ◽  
Small Depth ◽  
Major Stage ◽  
Maintenance Work ◽  
Different Depths ◽  
Maintenance Techniques ◽  
Pavement Structure

Treating cracks in asphalt pavements is a major stage of each maintenance work for engineers. The goal of any crack cure is to limit the water intrusion into underlying pavement structure layers. Such water infiltrates in to base layers of the pavement and may cause damage to the pavement structure. The previous studies focused on crack repairing materials and methods but not the bonding at the interface joint. In this study, the influence of the repairing materials and depth on the bonding at the interface joint using two repairing materials. Slabs were cast to simulate surface of road. Unlikely, slabs contain cracks in the middle of slab with different depths (35 mm, 50 mm, 70 mm). Consequently, these cracks were repaired with two methods; firstly, repairing them with RC+Sand and secondly, with Sika flex®-1a. The slabs were tested after being repaired to know the best method and depth. It has been concluded that slabs having cracks that have been repaired with RC+Sand increase failure load compared with empty cracks and cracks that have been repaired with Sika flex®-1a. Also, cracks with small depth that have been repaired with Sika flex®-1a increase failure load compared with empty cracks.

scholarly journals Influence of Ageing on Flexible Pavement Interface Bond under Repeated Shear Stresses

2020 ◽  
Vol 2 (2) ◽  
pp. 462-475
Author(s):  
Saad Issa Sarsam ◽  
Samah Abdulrazzaq AL Nuaimi
Keyword(s):  
Shear Strength ◽  
Permanent Deformation ◽  
Research Work ◽  
Application Rate ◽  
Shear Stresses ◽  
Interface Shear ◽  
Concrete Core ◽  
Application Rates ◽  
Tack Coat ◽  
Interface Bond

The durability of interface bond was not sufficiently taken into consideration, and the research work in this field is scares and scattered. The interface bond usually practices dynamic shear stresses throughout its service life while ageing due to volatilization provide stiffness at the interface. In this investigation, an attempt has been made to assess the durability of the interface bond in terms of resistance to ageing under repeated shear stresses. Two types of tack coat (Rapid Curing cutback RC-70 and Cationic Medium setting emulsion CMS) and three application rates have been implemented in the preparation of two layers slab samples (base overlaid by binder, and binder overlaid by wearing) courses using roller compactor. Asphalt concrete core specimens were obtained from the roller compacted slab samples and subjected to long term ageing, then the specimens were subjected to 1200 repeated shear stress cycles. The accumulation of permanent deformation was monitored. Afterwards, the specimens were tested for interface shear strength at 20 °C. Control specimens were also tested for comparison. It was concluded that ageing reduces the total microstrain for RC-70 tack coat by (43.6, 25.6, and 29.5) % and (50, 51.3, and 30.2) % for (binder-base) and (wearing-binder) interfaces for the application rate of (0.15, 0.33, 0.5) l/m2  respectively. However, ageing reduces the total microstrain for CMS tack coat by (37, 35.5, and 40.3) % and (45.2 , 49, and 46.8) % for (binder-base) and (wearing-binder) interfaces for the application rate of (0.1, 0.23, 0.35) l/m2  respectively. Ageing increases the interface bond shear strength by a range of (8-27)% for various interfaces, tack coat type and application rates.

Tensile, Torsional and Bending Strain at the Adhesive Rupture of an Iced Substrate

2009 ◽  
Author(s):  
Caroline Laforte ◽  
Jean-Louis Laforte
Keyword(s):  
Adhesion Strength ◽  
Ice Thickness ◽  
Stress And Strain ◽  
Substrate Roughness ◽  
Mean Values ◽  
Time Deformation ◽  
Bending Strain ◽  
Load Cells ◽  
The Mean ◽  
Major Factors

In order to develop an effective deicing device using mechanical deformation of substrates, the adhesive and/or cohesive strains of ice at rupture were measured for three different modes of solicitation: tensile, twisting and bending. A total of 108 icing/deicing tests were conducted with aluminum and nylon samples covered with hard rime ice deposits 2, 5, and 10 mm thick strained at various strains rates in brittle regime at −10°C. Real time deformation was precisely monitored using a strain gage fixed to the A1 interface, and force by means of load cells and a torque-meter. Deicing strain was determined at the time of ice detachment, which corresponds to a visible, instant change in the slope of stress-strain curves. The mean values of deicing strains, ε %, measured in tensile, torsion and bending experiments are respectively, 0.037 ± 0.015%, 0.043 ± 0.023% and 0.004 ± 0.003% As for adhesion strength, the highest values were obtained in tension, 4 MPa ± 50%, and the lowest in bending, 0.014 MPa ± 36%. In torsion, the value was intermediary, at 1.26 MPa ± 67%. Measurements also showed that deicing stress and strain tended to increase with substrate roughness, whereas they decrease with increasing ice thicknesses. In summary, this work points out the effects of two major factors on ice adhesion strength, the solicitation mode and the ice thickness. Finally these results suggest that the first criteria for a mechanical deicing device has to satisfy to be effective is to have the capacity to generating a strain at around 0.04% ice/substrate interface.

scholarly journals Comparison of Two Typical Professional Programs for Mechanical Analysis of Interlayer Bonding of Asphalt Pavement Structure

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Shuangxi Li ◽  
Liang Tang ◽  
Kang Yao
Keyword(s):  
Asphalt Pavement ◽  
Mechanical Analysis ◽  
Layered System ◽  
Professional Programs ◽  
Comprehensive Comparison ◽  
Modeling Calculation ◽  
Pavement Structure ◽  
Calculation Processing ◽  
Interlayer Bonding ◽  
Selection Of

The mechanical analysis of interlayer bonding problem of asphalt pavement is performed by the elastic layered system theory or finite element method (FEM); then, a lot of specialized programs based on the above theories emerged successively, of which BISAR3.0 and EverStressFE are quite representative. In order to further clarify the characteristics of BISAR3.0 and EverStressFE for investigating interlayer bonding problem of asphalt pavement, this paper will carry out a comprehensive comparison from the specific realization viewpoint, such as the principle of interlayer bonding, modeling, calculation processing, and result treatment, and a specific example will be given to compare and analyze their functions. The results indicate that the two programs have certain comparability in analyzing the interlayer bonding problem of asphalt pavement, which will contribute to the foundation for the rational selection of asphalt pavement structure mechanical analysis program.

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