Pavement Preservation Treatments Research Articles

Use of chip seal treatments to mitigate pavement roughness progression in cold regions

ABSTRACT Chip Seals are a type of pavement preservation treatment characterised by its ability to reduce pavement deterioration and restore surface condition. Chip seal performance, like other pavement preservation treatments, depends on several factors such as environmental conditions, traffic level and the condition of the existing pavement structure prior to treatment application. In cold regions, the presence of freeze and thaw cycles promotes the generation of thermal cracks and possible tenting distresses, consequently, pavement roughness has been a prominent parameter to assess treatment performance. The objective of this study was to evaluate the roughness progression on several chip seal configurations in a cold climate region, utilising a set of field performance data from the Pavement Preservation Group Study, a broader research study conducted by the National Center for Asphalt Technology and the Minnesota Department of Transportation’s Road Research Facility. The main findings indicate that chip seals provide a negligible effect on immediate roughness improvement; however, on a long-term basis, they provide a reduction in IRI progression over time. The magnitude of the IRI benefit is dependent on the type of chip seal implemented and the traffic level experienced.

Evaluation of Different Surface Treatments to Extend Pavement Life

When applied at the right time, pavement preservation treatments can restore a smooth, safe driving surface while delaying the cost for rehabilitation, resulting in reduced life cycle cost. The purpose of this study was to evaluate the performance of three preventive maintenance treatments applied to US 301 in Sussex County, Virginia, to extend pavement life. This paper documents the installation of a Cape seal application of fiber-reinforced chip seal (with microsurfacing on top) over an existing asphalt pavement. A performance comparison was made with more conventional surface treatment options: regular Cape seal (modified single chip seal with microsurfacing), and microsurfacing without a chip seal. Five years after the treatment application, a visual survey complemented by automated distress data from the Virginia Department of Transportation Pavement Management System showed that the section with fiber-reinforced chip seal and microsurfacing performed well with very little reflective cracking. The modified single chip seal with microsurfacing (i.e., regular Cape seal) also performed well, but reflective cracking was higher compared with the fiber-reinforced section. The control section (microsurfacing only) showed extensive cracking after 5 years. This study showed that pavement preservation activities such as the use of fiber-reinforced chip seal with microsurfacing and modified single seal with microsurfacing improved both the pavement condition and the surface characteristics in a very cost-effective manner (based on initial cost). However, long-term performance data are needed to evaluate the benefit/cost of each treatment.

Developing Network Slurry Seal Performance Models Using Pavement Management Systems Data

As a popular pavement preservation treatment, a slurry seal is typically included in agencies’ maintenance and rehabilitation toolboxes, in decision trees of pavement management systems (PMS), or both. However, performance prediction models for slurry seals are mostly anecdotal or at undertaken at project level. The goal of this paper is to illustrate a method of developing data-driven performance models for slurry seal applications for use at a network level. A total of 537,891 pavement condition records were collected from 18 different agencies in the United States using the Metropolitan Transportation Commission’s PMS program, StreetSaver®. Of these records, 1,195 slurry seal projects met the requirements to be utilized in the development of slurry seal performance models. The development of slurry seal performance models includes grouping project-level modeling results into functional classes, and testing and validating the slurry seal performance models with test cases as well as on actual data produced by agencies. The performance models for slurry seals placed on an asphalt concrete pavement vary depending mainly on the existing pavement’s performance, the timing of the slurry seal application, the functional class, and surface type. The data-driven slurry seal models improved the accuracy of predicting slurry seal performance using PMS. The models could also be used to develop beneficial area curves, which are useful in estimating the cost-effectiveness of slurry seals constructed at various pavement condition index values and in identifying the optimal timings for slurry seal applications at a network level.

Life-Extending Benefit of Chip Sealing for Pavement Preservation

Chip seals are effective pavement preservation treatments that are usually applied to address non-fatigue cracking, weathering, and raveling, to seal the surface, to delay oxidation, and, finally, to improve skid resistance. This study used field performance data of test sections from the Pavement Preservation Group Study being conducted by the National Center for Asphalt Technology and the Minnesota DOT’s Road Research Facility. Data from test sections located in a low-traffic-volume road with a hot, wet, no-freeze climate collected over a period of 7 years were used to evaluate the effect of several chip seal treatments. Treatments range from single layer to multilayer systems, and include different construction techniques such as rejuvenating scrub seal and fiber membrane. Also, a section was crack sealed before the application of a single layer chip seal to assess the benefits. A semi-parametric survival analysis was performed to determine the differences in median time to failure (MTTF) for different chip seal sections versus a controlled section—representing a “do-nothing” scenario. The results showed that the MTTF for a single layer chip seal ranges from 6.8 to 9.1 years depending on the pretreatment condition. Crack sealing before chip seal could extend the MTTF by an additional 1–3 years, depending on initial conditions. Double and triple layer chip seals extend the MTTF beyond 10 years. Finally, the scrub seal provided the highest benefits, with survival rates close to 100% after 10 years of performance.

Multi-objective optimization of pavement preservation strategy considering agency cost and environmental impact

Road network requires timely maintenance to keep pavement surface in good condition for reduction of fuel consumption with the limited budget. This study focused on development of pavement preservation strategies in the road network considering multi-objective optimization of agency cost and environmental impact (in terms of CO2 emission). Field data from long-term pavment performance (LTPP) database were used to quantify the impact of pavement preservation treatments (crack seal, chip seal, and thin overlay) on the changes of surface roughness. The emission rate functions of vehicles with respect to speed and pavement surface condition were developed using Motor Vehicle Emission Simulator (MOVES) with the updated tire rolling resistance coefficients. The multi-objective optimization problem was solved using the Simulated Constraint Boundary Model (SCBM) method. The final solution was recommended based on the minimized distance from the utopia point to the Pareto front. The results show that the optimization solutions are affected by the available budget, existing pavement condition, truck traffic, and unacceptable level of pavement roughness. For multi-objective optimization of minimizing both agency cost and CO2 emission, the recommended preservation treatments among different segments is a combination of crack seal and thin overlay in most cases. These findings can be used by highway agencies to make road maintenance decisions considering the tradeoff between agency cost and environmental impact.

Environmental impact comparison of new micro-milling and thin overlay and conventional milling for sustainable pavement preservation

Micro-milling and thin overlay, a new pavement preservation treatment developed and first implemented by the Georgia Department of Transportation (GDOT) in 2007, as an alternative pavement preservation to conventional milling and resurfacing, is used to remove and replace a thin, deteriorated open-graded surface layer (2.2 cm) without disturbing the sound underlying layer. This paper focuses on quantifying micro-milling and thin overlay’s environmental impacts by comparing conventional milling and overlay with micro-milling and thin overlay to complement the previous economic impact study. The environmental impacts are quantified using a pavement construction decision tool entitled Pavement Life-Cycle Assessment Tool for Environmental and Economic Effects (PaLATE). The results show a 60% reduction in all environmental impacts assessed, including energy usage, water consumption, and CO2 emissions largely due to the savings in asphalt needed. Results have demonstrated that this new method is a promising pavement preservation alternative that is environmentally sustainable. This paper provides quantitative comparison information useful for transportation agencies in selecting sustainable pavement preservation alternatives.

Developing Life-Extending Benefit Curves for Asphalt Pavements with Preservation Treatments

Over time, new pavements deteriorate due to the effect of traffic loads and the environment. If appropriate treatments are applied during the early stages of deterioration, it is possible to improve pavement conditions and extend pavement life without increasing expenditures. The National Center for Asphalt Technology (NCAT) has partnered with the Minnesota DOT’s Road Research Facility (MnROAD) to conduct a pavement preservation study that evaluates the life-extending benefit of a variety of preservation treatments, ranging from crack sealing to thin overlays. The objective of this research partnership is to develop performance curves for the treated pavements under different conditions (climate, traffic and initial condition of the pavement). In this study, full-scale test sections were treated first in a southern location (Alabama) on roadways subjected to both low and high traffic levels, starting in the summer of 2012. The experiment was extended in 2016 to include test sections in a northern location (Minnesota) to evaluate the effect of cold climate, also for low and high traffic levels. Throughout this time, cracking, roughness, rutting and macrotexture data were collected biweekly to evaluate pavement performance. The observed trends in the first years of the experiment indicate that there is not a significant variation in roughness or rutting over time, and that performance is mainly affected by the amount of cracking. Furthermore, the condition of the pavement at the time of treatment significantly affects the performance of the treated pavements, as pavements that are treated while still in good condition tend to remain in that category for a longer time. The results also demonstrate the effectiveness of applying pavement preservation treatments versus the “do nothing” scenario. After 4.8 years, the amount of cracking observed is less than the amount expected if the sections were left untreated, even for sections treated with applications that are not designed to address cracking. The results shown in this paper should be considered preliminary and used with caution. Data collection efforts continue in both southern and northern locations with the objective of determining the life-extending benefits of pavement preservation treatments as a function of initial condition, climate and traffic.

Environmental and Economic Analysis of Selected Pavement Preservation Treatments

Pavements are one of the highest assets and represent massive investment. The need to design and provide a sustainable maintenance service is becoming a priority and this comes mutually with the intentions to reduce impacts caused by maintenance treatments to the environment. This paper through a case study presents a Life Cycle Cost and Assessment technique during a 30 year analysis period to measure the cost effectiveness, embodied energy and carbon emissions of selected preservation treatments. These treatments can either be applied separately or in combination during the preventive maintenance of road pavements. This study entails three life cycle phases of material extraction and production, transportation and construction of maintenance activities. Through a literature review, raw materials energy and emission inventory data was averaged followed by the analysis of the equipment involved by using the specific fuel consumption to calculate the energy and emissions spent by the machine and finally the selected treatment energy and emissions was computed. Results show that preservation treatments can have an LCC of 30-40 % and embodied energy and carbon emission of 3-6 times lower than the traditional approach. This study bridges gaps in literature on integrated evaluation of environmental and economic aspects of preservation treatments.

ζ Potential as a Measure of Asphalt Emulsion Stability

Asphalt emulsions are most often oil-in-water emulsions widely used in pavement preservation treatments as a result of lower application temperatures and versatility for many pavement preservation ...

Life cycle cost analysis of Portland cement slurry seal and microsurfacing to correct rutting

ABSTRACTPortland cement slurry seal and microsurfacing can both be used as pavement preservation treatments to fill ruts, which extends service life and decreases road surface life cycle cost. Microsurfacing has a history for being a technically effective and cost-efficient solution for correcting pavement rutting in both asphalt and concrete pavement surfaces. On the other hand, Portland cement slurry seal is a relatively new product that provides an alternative rut filling solution. The potential of both treatments as rut fillers is generally unrecognized and as such, they are both underutilized in that role. This paper compares the life cycle costs of both treatments, using friction data as the primary performance indicator derived from field trial skid data collected over a period of 36 months on the same highway. The paper finds that each alternative performed comparably with regard to surface friction deterioration, and the life cycle cost output was such that either treatment is an economically feasible solution for filling ruts in both asphalt and concrete pavements.

Life-Extending Benefit of Crack Sealing for Pavement Preservation

Crack sealing and filling is used as a pavement preservation treatment to prevent water infiltration and loss of load-carrying capacity, hence extending the life of the pavement. This study used field performance data of test sections from the Pavement Preservation Group (PG) Study being conducted in part by the National Center for Asphalt Technology (NCAT). Data from test sections located in a low traffic volume road with a hot, wet, no-freeze climate collected over a period of more than 6 years were used to evaluate the effect of crack sealing and filling, either as a stand-alone treatment or in combination with other surface treatments. A semi-parametric survival analysis was performed to determine the difference in median time to failure (MTTF) for sections with and without crack sealing. The results showed that when used as a stand-alone treatment on a pavement in “good” condition, the life-extending benefit from crack sealing/filling could not be calculated for the selected analysis period because the MTTF would not be reached within 10 years. The estimated benefit for pavements in “fair” and “poor” condition ranged from 1.1 to 7.3 years, depending on pretreatment condition and travel lane. If used in combination with a chip seal, the additional life-extending benefit for a pavement in “good” condition is approximately 2 years, and is slightly decreased to approximately 1.5 years if the pavement is in “fair” to “poor” category. Test sections continue to be monitored as part of a broader long-term study.

Performance of Chip Seal Treatments in Two Different Climatic Regions

Over time, new pavements deteriorate because of the effect of traffic loads and the environment. Pavement preservation treatments, such as chip seals, are a cost-effective alternative for extending the service life of the pavement without incurring in costly rehabilitation or reconstruction activities. Chip seals are preservation treatments that can help protect the pavement structure, reduce the rate of pavement deterioration, improve skid resistance, and address minor surface problems. As part of the National Center for Asphalt Technology and Minnesota Road Research Facility Pavement Preservation Study, chip seal test sections were placed on low-traffic-volume roads in Alabama and Minnesota. The two locations were selected to represent different climate conditions. Lee County Road 159 in Auburn, Alabama, is subjected to warm, wet, no-freeze climate, while County State Aid Highway (CSAH 8) is located in a cold, wet, freeze area in Pease, Minnesota. Treatments have been in service for approximately 6 years in the southern sections, and 2 years in the northern sections. During this time, cracking, roughness, rutting, and macrotexture data were collected periodically to evaluate pavement performance. The results determined that cracking is a predominant form of distress for these treatments. While the treatments are not expected to address rutting or roughness, the results indicated little variation in the case of the southern treatments, and an increasing trend in international roughness index in the northern sections, likely related to the appearance of thermal cracking. Macrotexture data may be used to assess the functional life of the treatments.

Role of Preventive Treatments in Low-Volume Road Maintenance Program: Full-Scale Case Study

The lack of information on reliable life-extending benefit for pavement preservation treatments led the National Center for Asphalt Technology (NCAT) to conduct a preservation study applying preservation treatments on a low-volume county road in Auburn, Alabama, which began in 2012. The primary objective of the study is to develop performance models for preservation treatments to be used in pavement management systems. Performance measures including rutting, cracking, and roughness are collected on a regular basis to the present date. Among all the collected measures, only cracking shows an upward trend and therefore was used in this study as the performance index for the analysis. The present study aims to implement a semi-parametric survival analysis technique to assess the effectiveness of treatments used, and to investigate associated risk factors. The study confirms that preservation strategies significantly decrease the risk of failure when compared with a “do-nothing” scenario. It was found that initial condition, treatment family, recycled material usage, and crack sealing application have a significant impact on future deterioration. It is also concluded that survival analysis techniques are useful tools in aiding decision makers in the selection of proper treatment choices.

Exploring the influence of pavement preservation, maintenance, and rehabilitation on Arkansas’ highway network: an education case study

ABSTRACT There is significant literature available on pavement preservation, but the information available to date is highly regional and spread across several years, preventing a simple comparison. A new website, RoadResource.org, is now available that can compare twenty-two treatment types and quantifies the impact of these treatments through four calculators. The first calculator, Life Cycle Cost, indicated that treatments such as fog seals can save approximately 40 billion over a fifty year design period in the state of Arkansas compared to major mill and fills if applied across the entire network. The second calculator, Equivalent Annualized Cost, showed that the assumed life extension of a treatment can equate the cost of preservation treatments and rehabilitation treatments. The third calculator, Remaining Service Life, indicated that all twelve pavement preservation treatments provided a net gain in lane-kilometer-years, while only two of the nine rehabilitation/reconstruction treatments showed a net gain. Finally, the fourth calculator, Cost Benefit Value, showed promise as a tool to rank treatment strategies but appears to require human judgment for the inputs. RoadResource.org is a powerful tool that can help agencies better understand pavement preservation, maintenance, and rehabilitation.

Development of performance related specifications for chip seal treatments

ABSTRACT Road agencies are increasingly incorporating performance-related specifications (PRS) in construction contracts to specify quality in terms of parameters related to desired long-term performance. PRS provides a means to account for the value lost or gained by the variances of the designed performance parameters from the specified target values. The use of PRS for pavement preservation treatments (e.g. chip seals) has been generally non-existent. The objective of this paper is to establish a step-by-step procedure for formulating chip seals PRS guidelines. The percent embedment (PE) of aggregates into emulsified asphalt was selected as the acceptance quality characteristic (AQC). Chip seal specimens with varying percent embedment levels were prepared using aggregate and emulsion types in Michigan. Aggregate loss and bleeding were selected as performance indicators. Laboratory tests were conducted to compute PE, aggregate loss and bleeding for the chip seal specimens. Relationships were developed between quality measures, service life, and pay factors. The expected pay curves were developed based on quality measures and were used to establish acceptable and unacceptable quality levels. The pay factors were evaluated to ensure fair payments for the quality of work produced. The work presented will provide the general guidelines for developing PRS for chip seal projects.

Time-Dependent Water Infiltration Resistance of Thin-Lift Asphalt Overlay Longitudinal Joints

AbstractIn recent years, the Mississippi Department of Transportation (MDOT), among others, has begun considering thin-lift overlays (e.g., 2.5 cm or less) as a pavement preservation treatment; how...

Universal Method to Measure Water Infiltration into Asphalt Pavements Independent of Pavement Preservation Surface Treatment

In recent years, greater focus has been placed on pavement preservation treatments, where one of the primary goals is to seal an existing pavement (especially cracks) to preserve it from further oxidation (i.e. decrease its permeability). The industry needs the ability to measure the effectiveness of these surface treatments; a single universal method that could be used for this purpose would be ideal, especially if traditional asphalt pavement surfaces could also be evaluated or field and laboratory measurements successfully related. This paper’s objective is to present a simple permeameter device, the Mississippi permeameter (MSP), for measuring water infiltration into asphalt pavements independent of the surface (e.g. dense-graded asphalt (DGA), chip seal). In this paper, the MSP was evaluated against traditional field and laboratory permeameters (e.g. NCAT permeameter) on a range of surfaces from open-graded friction course (most permeable) to DGA (most common) to chip and scrub seals (least permeable, roughest texture, most difficult to measure). The MSP provided measurements as reasonable as those of existing permeameters and was also successfully used to test chip and scrub sealed cracks, which is beyond existing permeameters’ abilities. Additional refinements are needed for relating field and laboratory measurements, but the MSP concept appears promising and worth pursuing given the increasing pavement preservation focus.

Surface texture and friction characteristics of diamond-ground concrete and asphalt pavements

Abstract Recently, diamond grinding has gained increasing attention as pavement preservation treatment to restore desired surface characteristics, particularly friction. Compared to other pavement preservation treatments such as surface overlays and high friction surface treatments, diamond grinding may cost less, save construction time, or require minimum maintenance. Diamond grinding produces longitudinal, continuous, and line-type texture that contains corrugations with evenly spaced ridges. The improved surface texture will immediately enhance pavement surface friction and reduce the possibility of hydroplaning in rainy weather. However, little information has been documented on the texture characteristics and long-term friction performance of diamond-ground pavements. A field evaluation was conducted to examine the surface texture and friction characteristics in diamond-ground concrete and asphalt pavements by the authors. Five pavement test sections, including two diamond-ground concrete pavements, one diamond-ground concrete bridge deck, one diamond-ground asphalt pavement, and one transversely tined concrete pavement, were selected for evaluation. Laser scanner testing was performed to capture both macro and microtexture profiles. Locked wheel testing was performed to measure the friction numbers. The test results were examined and compared so as to evaluate two performances, after construction and long-term friction performance of diamond-ground pavements. It was found that longitudinal diamond grinding can provide durable, satisfactory surface friction performance for both concrete and asphalt pavements.

Subsurface Condition Evaluation of Asphalt Pavement for Pavement Preservation Treatments

Abstract The Indiana Department of Transportation (INDOT) has developed a guideline for evaluation of subsurface condition, a project-level evaluation for applicability of Indiana pavement preservation treatments (PPT). The developed guideline, using ground penetration radar (GPR) measurements, surface distress, and laboratory tests, determines the pavement subsurface distress severity and its distribution. The guideline also incorporates the newly developed water stripping severity test utilizing the digital image processing. The guideline has hierarchal evaluation system based on the type of data available for the test section. Level 1 is selected if GPR analysis data is available, level 2 is selected if surface distress data is available, and level 3 is used for all other cases. In addition, the subsurface distress distribution analysis tool (DCUAL) provides the locations of the PPT applicable sections. Case studies were conducted to provide aid to better understand the guideline, to present the example evaluation results upon the application of the guideline, and to validate the applicability of guidelines. Three test roads treated with PPTs within two to three years in Indiana were selected, and different evaluation levels were applied to the test roads. Level 1 and level 2 were applied for state road (SR) SR-70, and level 2 and 3 was applied for SR-257 and SR-43, respectively. Level 1 and level 2 analyses in the case study showed a good agreement with the case of the non-uniform subsurface distress distribution. In the process of determining the PPT applicability, pavements with the overall score of 60 or higher were found to be suitable for PPTs for all three levels of analysis and suitable for the Indiana State Roads having average annual daily traffic of less than 9000. Overall, the case study validated that the guideline provides a consistent, rational, and data-driven decision-making process for the applicability of the project-level pavement preservation program.

THE EFFECT OF PRESERVATION MAINTENANCE ACTIVITIES IN ASPHALT CONCRETE PAVEMENT SUSTAINABILITY

Pavement infrastructure is crucial to quality lifestyle and affluence of society. Since the pavement structure deteriorates after a while, appropriate pavement preservation maintenance is essential to attain a superior performing, safety, and economic pavement network for the users. Nowadays, within a modern society resources and budget are restricted that make it necessary for transportation agencies to discover approaches to use the resources to optimize benefits included in daily operation. Simultaneously, focus on the idea of environmental sustainability has increased substantially. Pavement preservation assists environmental sustainability by preserving energy, raw materials, and mitigating greenhouse gases (GHG) by maintaining good roads in the perfect condition. Thereby, a sustainable pavement maintenance program should look into allocating budget and resources to pavement preservation. Various types of pavement preservation treatments use different levels of energy and produce GHG emissions. Preservation treatments considered in this study included thin hot-mix asphalt (HMA) overlay, chip seal, slurry seal and crack seal. This research states the methodology in sustainable pavement preservation maintenance. Its focus is on quantifying and recognizing which of these pavement preservations practices minimize environmental impacts. As the economic is one of the components in triple bottom-line in sustainability, the next step is focusing on cost-benefit of preservation maintenance activity and comparing by rehabilitation activity. This research aims to persuade pavement organization to apply correct perseverance activity on the right time and proper manner to enhance sustainable development.