Crack Sealing Research Articles

Path-Planning Algorithm for Automated Pavement Crack Sealing Based on Postman Problems

Path-Planning Algorithm for Automated Pavement Crack Sealing Based on Postman Problems

Incomplete Crack Sealing Causes Localization of Fracturing in Hydrothermal Quartz Veins

AbstractCyclic microfracturing and epitaxial crystal growth have long been recognized in crack‐seal veins, but an understanding of a single crack‐seal cycle is still missing. Here we present a phase‐field model that includes both fracture mechanics of crack propagation, and epitaxial crystal growth on the fracture walls, repeating this cycle multiple times in a polycrystalline, microporous quartz rock. Our simulations have two end members: If a vein completely seals, it is stronger than the host rock, cracking is delocalized, forming many single‐seal microveins. Incomplete sealing makes the vein weaker than the host rock and localizes the new fracture inside the vein, leading to multi‐crack‐seal. We suggest that the sealing degree is a key parameter in hydrothermal systems and multi‐crack‐seal veins are long‐lived, microporous sites of mechanical weakness. We generalize the phase‐field approach to conduct probabilistic simulations in between these two types, and show how systems of microveins and multi‐crack‐seal veins emerge.

Quantitative Assessments of Crack Sealing Benefits by 3D Laser Technology

Crack sealing is one of the most commonly used methods to preserve asphalt pavements. However, quantification of crack sealing benefits (or the long-term delaying effects of crack sealing on crack propagation) remains unavailable because field crack lengths could not be measured accurately and efficiently. In this study, 3D laser technology is proposed to measure and compare the growth of crack lengths between sealed and non-sealed pavement sections and, for the first time, to accurately and efficiently quantify the crack sealing benefits. To validate the proposed method and find adequate treatment timing (or conditions), nine field sites in Georgia, U.S., with different pavement pre-treatment conditions and roadway environmental factors were monitored over 3 years from December 2016 to September 2019. The study results showed that crack sealing can retard crack growth by 40%–128%, and such delaying effects are more significant under better pavement pre-treatment conditions. The findings suggest that transportation agencies can prolong the service life of pavements by applying crack sealing before the pavement condition becomes poor. In addition, this work has been proved to be very valuable for transportation agencies to determine the best timing and treatment criteria for crack sealing.

Decision Trees for Selecting Asphalt Pavement Crack Sealing Method

Crack sealing is an important preventive treatment in the pavement preservation program. To achieve a cost-effective crack seal, it is crucial to select a proper crack sealing method. In Minnesota asphalt pavement cracks are sealed using both the clean-and-seal and rout-and-seal methods; however, there is no guideline for choosing the most suitable crack sealing method. This study deals with a literature review, an online survey, crack seal performance data collection, cost-effectiveness analysis of the crack sealing methods, life cycle cost analysis, and development of two decision trees to aid in selecting the most suitable crack sealing method. The first, which can be used in the pavement management system, needs information such as crack severity, pavement type (new versus overlay), pavement analysis period and design life, traffic level, and crack seal sequence (first, intermediate, or last). The second decision tree, which is a simplified version of the first and can be used by preventive maintenance crews, requires less information, such as crack severity, traffic level, and place in the crack sealing sequence.

Improve Mass Concrete by Controlling the Crack Sealing Mechanism Using Microcapsules of Zinc Oxide

This paper examines the structural, workability, physical and mechanical properties of (mass concrete) with the inclusion of microcapsule of Zinc oxide (ZnOMC) with a size (0.5) µm and in different percentages (0, 0.5, 1 and 1.5) % of cement weight. The proportions of the concrete mixture were (1:2:4.8) and the water-cement ratio (W/C) was 0.4. 0.6% of Superplasticizer (SP) by weight of cement with all concrete mixtures was added. An SEM analysis employed to obtain a better view of the concrete behavior with ZnOMC. Referring to the analysis and discussion, it was found that the types of microcapsule used to have an effective effect on the compressive and flexural strength and mechanism of sealing the crack, also the highest percentage of microcapsule which there has a positive contribution towards mass concrete properties have been recorded.

Cost Effectiveness and Optimal Timing of Crack Sealing in Asphalt Concrete Overlays

Crack sealing of asphalt concrete (AC) overlays is an important component of pavement preventive maintenance. The objectives of this study were to evaluate the cost effectiveness (CE) of crack sealing applied on AC overlays (flexible and composite) in Louisiana considering the pretreatment overlay conditions and to determine the optimal timing of crack sealing. To achieve these objectives, AC overlay, crack sealing, and chip seal projects in Louisiana were identified for data collection. Based on the data collected, the equivalent annual cost (EAC), life-cycle cost analysis (LCCA), and CE approaches were employed to identify the optimal timing of crack sealing. Additionally, a case study was considered including five different alternative strategies for which the LCCA was calculated to identify the optimal long-term strategy as well as the corresponding optimal timing of this strategy. The results of the cost-benefit analysis for the field projects and case study were compiled and analyzed to provide the final recommendation for crack sealing. Results indicated that the cost effectiveness of crack sealing is optimum when the pretreatment overlay condition ranges between 81 and 89. When the pretreatment overlay condition exceeds 90, crack sealing should not be applied. Based on the results of this study, a series of automated Microsoft Excel spreadsheets were developed to allow the user to predict the cost effectiveness and optimal timing of crack sealing knowing the project conditions and costs without the need for additional calculations.

Use of LTPP Data to Quantify Moisture Damage under Crack Sealing and Surface Treatments in Asphalt Pavements

Crack sealing and seal coats are used to prevent the ingress of water into the pavement, thus delaying its deterioration. Yet, earlier studies indicated that sealing pavements in areas with high ground water table (GWT) prevented moisture from escaping upwards through the cracks of asphalt pavements, therefore, accelerating stripping. The objectives of this study were to determine whether these treatments contribute to stripping in Asphalt Concrete (AC) and/or moisture accumulation in the base and to evaluate the effect of GWT, rain, and traffic on subsurface failures under these treatments. In this study, nine test sections included in the Long-Term Pavement Performance (LTPP) program and several field chip seal projects in Louisiana were analyzed. Results indicated that these treatments do not contribute to stripping. However, the cause of common stripping under these treatments in the Southern United States is moisture entrapment under the AC layer under shallow GWT conditions, which is also the key contributor to stripping under unsealed sections.

Field Evaluation and Cost Effectiveness of Crack Sealing in Flexible and Composite Pavements

One of the most common methods used to treat longitudinal and transverse cracks is crack sealing (CS), which is categorized as a preventive maintenance method. Field performance and cost-effectiveness of this treatment widely vary depending on pavement conditions and installation of the material. The objective of this study was to evaluate the field performance and cost-effectiveness of CS in flexible and composite pavements in hot and wet climates such as Louisiana, and to develop a model that would quantify the expected benefits of CS given project conditions. To achieve this objective, 28 control sections that were crack-sealed between 2003 and 2010 were monitored for at least four years. These sections included flexible and composite pavements, sealed and unsealed segments, and varying traffic levels. The performance of these sections was evaluated for the random cracking index (RCI) and roughness index (RI). Based on the results of this analysis, it was concluded that CS only has a significant impact on random cracking. When compared with untreated segments, CS extended pavement service life (PSL) by two years. When compared with the original pavement, CS extended PSL by 5.6 and 3.2 years for flexible and composite pavements, respectively, if applied at the correct time. The cost-benefit analysis indicated that CS is cost-effective whether asphalt emulsion or rubberized asphalt sealant is used. A non-linear regression model was developed to predict the extension in PSL because of CS without the need for performance data based on the average daily traffic (ADT), pavement type, and prior pavement conditions.

Use of Crack Characteristics in Crack Sealing Performance Modeling and Network-Level Project Selection

Crack sealing (CS) and crack filling (CF) are commonly used crack treatment methods. However, the study of their performance is still very limited, making it difficult for highway agencies to systematically and optimally select network-level CS-CF projects within available budgets. To address this issue, a generalized performance model for CS-CF–treated pavements is proposed. Detailed crack characteristics—including crack type, density, and width—are employed in the model. In the proposed performance model, crack density related to three types of cracks (transverse cracks, nonwheelpath longitudinal cracks, and wheelpath longitudinal cracks) is used to determine performance gain. Two discount functions are incorporated to consider the negative impact caused by alligator cracks and cracks that are very tight or very wide. The proposed model is instantiated and estimated using the practices of the Georgia Department of Transportation on CS and CF and the department’s pavement distress survey protocol. The case study—which uses three-dimensional laser data collected from a 1-mi pavement section on State Route 26 (US-80) near Savannah, Georgia, from 2011 to 2016—validates the feasibility and reasonableness of the model. An integer programming method is formulated for network-level CS-CF project selection. The testing results of 53 pavement segments show that the model and programming method can be used to select CS-CF projects within budget constraints while maximizing the length-weighted average performance gain. The proposed performance model and integer programming method show promise for use in incorporating CS and CF into a highway agency’s pavement management system. Conclusions and recommendations are offered.

Mobile Robots for the Concrete Crack Search and Sealing

This study proposes a multi-robot system, using multiple autonomous robots, to explore concrete structures and assist in their maintenance by sealing any cracks present in the structure. The proposed system employed a new self-localization method that is essential for autonomous robots, along with a visualization system to recognize the external environment and to detect and explore cracks efficiently. Moreover, more efficient crack search in an unknown environment became possible by arranging the robots into search areas divided depending on the surrounding situations. Operations with increased efficiency were also realized by overcoming the disadvantages of the infeasible logical behavioral model design with only six basic behavioral strategies based on distributed control-one of the methods to control swarm robots. Finally, this study investigated the efficiency of the proposed multi-robot system via basic sensor testing and simulation.

Evaluation of Premature Failures of Asphalt Pavement Crack Sealing Bands

AbstractCompared to conventional hot-applied asphalt sealant, the new cold-applied crack seal bands have outstanding advantages such as high installation efficiency, fewer secondary failures, and more environmentally friendly. However, some new failure modes happen during field application. Based on field investigation and laboratory testing, the short-term and long-term failure modes of seal bands were identified in this study. The laboratory testing methods were then developed to evaluate the short-term or premature failures and explore the causes of the short-term failures of installation failure or bending, unevenness, and stripping. The strategies to prevent and reduce the short-term failures of crack sealing bands were recommended regarding material selection and construction control.

Development of a crack recognition algorithm from non-routed pavement images using artificial neural network and binary logistic regression

Road pavements require periodic maintenance and repair, which as a national infrastructure facility requires an enormous annual. The crack sealing method has been widely used in the implementation of pavement repair and maintenance. Developed countries have recognized the importance of the crack sealing method and have continuously pursued research on the development of automated crack sealing equipment such as ARMM(Automated Road Maintenance Machine), OCCSM(Operator Controlled Crack Sealing Machine), and TTLS(Transfer Tank Longitudinal Sealer) since the early 1990s. In 2004, APCS(Automated Pavement Crack Sealer), which seals routed cracks on the road, was developed in Korea, and since 2009, the development of ACSTM(Automated Crack Sealer with Telescopic Manipulator) for the sealing of non-routed cracks has been underway. Because the non-routed crack is characterized by a very narrow width of 2~3 mm, in comparison to the routed crack, it is necessary to use high-resolution pavement images of over five million pixels in order to detect non-routed cracks. Moreover, it is very effective to employ intelligent algorithms that can distinguish cracks and noise from the high-resolution images using the morphological characteristics of non-routed crack. The purpose of this study is to develop an intelligent algorithm, which can distinguish crack and noise by eliminating the noise, to enable the ACSTM equipment in easy detection of the non-routed cracks. This study subjects the binary high-resolution images of the non-routed cracks to artificial neural network and binary logistic regression analysis for this purpose of intelligently discerning the crack images from the noise. Actual pavement images have been used to compare and verify the accuracy of the proposed algorithm in identifying cracks.

Field Investigation and Laboratory Evaluation of Asphalt Pavement Crack Seal Band

Crack sealing and filling are two of the main traditional techniques of asphalt pavement preventive maintenance. However, these techniques have the shortcomings of low operating efficiency and poor performance such as secondary cracking and edge failure. In this paper, the investigation results of field performance of crack seal band are presented. The seal band is a promising material of crack repair because it results in fewer secondary cracks and greater operating efficiency (two to four times more efficient than crack sealing). However, the field investigation also revealed four major failure modes of seal band, namely, unevenness, cohesion failure, adhesion failure, and pullout that provide the demand to carry out laboratory studies on the properties of seal band material. The following standards are referenced in the studies: (1) standard of hot-applied sealant, (2) standard of building waterproof roll, and (3) standards of related enterprises. Six evaluating test methods are put forward based on the laboratory studies, including: thickness meterage, width meterage, cone penetration test, softening point test, pullout test, and bond test. Fifteen seal band samples are tested in a laboratory evaluation. Based on the field investigation and test results, the technical requirements of different seal bands used in different areas are proposed.

Practical, Interactive, and Object-Oriented Machine Vision for Highway Crack Sealing

This paper discusses a machine vision system that is used to find pavement cracks for a robotic crack sealing machine. The system includes a high-resolution digital camera which captures live or still images of the robot's 3.7 m by 4.3 m (12 ft by 14 ft) workspace. The live images are used for overall crack searching, whereas the higher resolution still images allow for accurate robot path planning. The operator interacts with the system to select cracks to be sealed. With the significant advancement in graphical and object-oriented programming, interactive and object-oriented machine vision offers advantages over fully automatic machine vision in that it is much less expensive, requires less complex hardware, its algorithms are much simpler, easier to develop and implement, and the operation can be much easier, faster, and more accurate reliable. The machine vision system described has been successfully used for sealing many actual highway pavement cracks.

Field and Laboratory Evaluations of Hot-Poured Thermoelastic Bituminous Crack Sealing of Asphalt Pavements

This paper describes the results of field and laboratory tests evaluating four configurations and three materials used for crack surfacing. Crack surfacing, as defined in this paper, is the sealing of cracks over 1 in. (25 mm) wide in asphalt pavements. Laboratory testing using the thermal stress restrained specimen test (TSRST; AASHTO TP 10-93) determines the temperature at which a specimen with its ends restrained fails due to thermal contraction. Field studies evaluate the performance of two materials with the uniform overband configuration on three roads in Wyoming. All crack surfacing materials are commercially available hot-poured thermoelastic bituminous products. Overband configurations are found to be the preferred method for applying crack surfacing, based on the TSRST. Failure modes are evaluated and generally found to propagate from the interface between the surfacing material and the pavement to which it is bonded. Field studies indicate that traffic and snowplowing have a significant influence on the performance of crack surfacing. Cracks sealed with the same configuration and the same material performed substantially better on US-26 than on I-25 over the same time periods. The only obvious difference between the two is that I-25 has three to four times as much traffic and correspondingly greater snow control efforts. This study concludes that materials, configurations, and traffic or snowplowing frequency influence the performance of crack surfacing.

Field and Laboratory Evaluations of Hot-Poured Thermoelastic Bituminous Crack Sealing of Asphalt Pavements

This paper describes the results of field and laboratory tests evaluating four configurations and three materials used for crack surfacing. Crack surfacing, as defined in this paper, is the sealing of cracks over 1 in. (25 mm) wide in asphalt pavements. Laboratory testing using the thermal stress restrained specimen test (TSRST; AASHTO TP 10-93) determines the temperature at which a specimen with its ends restrained fails due to thermal contraction. Field studies evaluate the performance of two materials with the uniform overband configuration on three roads in Wyoming. All crack surfacing materials are commercially available hot-poured thermoelastic bituminous products. Overband configurations are found to be the preferred method for applying crack surfacing, based on the TSRST. Failure modes are evaluated and generally found to propagate from the interface between the surfacing material and the pavement to which it is bonded. Field studies indicate that traffic and snowplowing have a significant influen...

Performance of Flexible Pavement Maintenance Treatments in the Long-Term Pavement Performance SPS-3 Experiment

A study was conducted to assess the relative performance of different flexible pavement maintenance treatments, including the influence of pretreatment condition and other factors. The data used in the study were drawn from the Long-Term Pavement Performance Studies' Specific Pavement Studies (SPS) SPS-3 experiment. The maintenance treatments used in the SPS-3 experiment are thin overlays, slurry seals, crack seals, and chip seals. The initial and long-term effects of the maintenance treatments on international roughness index (IRI), rutting, and cracking were analyzed, as were the influences of time, truck traffic, pretreatment condition, and climate. Thin overlays were found to be the most effective of the treatments studied, followed by chip seals and slurry seals. Crack sealing did not demonstrate any beneficial initial or long-term effect with respect to IRI, rutting, or cracking.

Robotic Machine for Highway Crack Sealing

An operator-controlled crack-sealing machine was developed and tested at the Advanced Highway Maintenance and Construction Technology (AHMCT) Research Center at the University of California, Davis. The machine, integrated onto a single truck, provides ease of operation and a simple, automated method of sealing random pavement cracks. The operator provides the machine its tasks and is the decision maker; the machine automatically performs the repetitive and dangerous tasks of mapping pavement cracks, creating seal paths for the robot, and sealing the cracks. The operator communicates with the machine through a simple user interface adjacent to the driver. This operator control approach drastically reduces the machine’s control complexity relative to fully automated crack-sealing machines. To be able to seal cracks within a full lane without intruding into adjacent lanes, a telescoping long-reach robotic arm was developed that can position the sealing head mounted to its end in a large 3.7- x 4-m (12- x 13-ft) workspace, within 0.4 mm (1/64 in.) at a traverse speed up to 1 m/s (3 ft/s). A special sealant applicator that deploys a pressurized reservoir was developed to allow high-speed and automated sealing operations. A 100-Mbps fast Ethernet and 10-Mbps wireless control network allows for distributed real-time motion control, input/output control, and machine vision. A fully object-oriented, multithreaded Internet-based software architecture allows reliable and efficient system integration and provides an interactive and responsive user interface for feature-rich and easy imaging, path planning, and system control.

Cost-Effectiveness of Joint and Crack Sealing: Synthesis of Practice

The sealing and resealing of joints and cracks in pavements is assumed to be an important component of pavement maintenance. If performed effectively and timely, sealing may retard pavement deterioration and prolong pavement life. Historically, sealing and resealing has been an accepted practice by state highway agencies (SHAs) but this practice has recently been challenged by research. Additionally, studies that provide a clear quantitative defense that joint/crack sealing is cost effective are few in number and limited in scope. Millions of dollars are spent annually by SHAs to accomplish joint and crack sealing with no quantitative evidence to justify the expenditure. The sealing operations are conducted simply because the “industry” assumes the benefits of sealing outweigh the costs. The objective of this research was to investigate the cost-effectiveness of joint/crack sealing specifically in relation to pavement performance. This report represents a synthesis of practice (extensive literature review and survey of practice) used for determining whether further research was needed to determine the cost-effectiveness of crack/joint sealing in Indiana. Ultimately, it led to the development of a comprehensive field study that the Indiana Department of Transportation is sponsoring.

Sealant Degradation during Crack Sealing of Pavements

Application practices of bituminous hot-poured crack sealants, typically used to effect repairs on pavements, were monitored in the field and heating conditions were reproduced in the laboratory. From viscometry, thermogravimetry, and tensile testing measurements, it was found that sealants degrade upon heating at recommended installation temperatures. Consequently, given the level of product degradation observed from laboratory evaluations, it is not expected that a consistent low temperature sealant performance could be obtained in the field. These conclusions help explain the number of premature sealant failures that exist despite the fact that these materials may be in accordance with the requirements in ASTM D 3405.