Development of Emulsion Residue Testing Framework for Improved Chip Seal Performance

2012 ◽  
Vol 2293 (1) ◽  
pp. 106-113 ◽  
Author(s):  
Andrew J. Hanz ◽  
Petrina Johannes ◽  
Hussain U. Bahia

To promote sustainability and optimize funding, state highway agencies are integrating pavement preservation strategies into the management of their roadway networks. Chip seals, a prominent pavement preservation alternative, are traditionally being used on low-volume roads with success in many states. However, as advancements in emulsion formulations continue and the use of chip seals on medium- and high-traffic facilities becomes more prevalent, there is a need to improve the methods to select and specify chip seal emulsions. The objective of this study was to develop an emulsion testing framework that captured properties related to critical distresses observed for in-service chip seals and considered the effects of traffic, environment, and aging. The proposed testing framework recommended the use of the dynamic shear rheometer and bitumen bond strength test to evaluate high-, intermediate-, and low-temperature performance. The testing protocols were applied to recovered and pressure aging vessel–aged emulsion residues from six emulsions widely used in Wisconsin, which included two emulsifier chemistries and two types of modification. The base binders before emulsification were also tested to assess the effects of the emulsification process. Results indicated that the proposed test methods could characterize material performance and differentiate between emulsion types and types of modification; however, additional research is needed to establish the relationship between laboratory-measured residue properties and performance of the full chip seal.

2015 ◽  
Vol 42 (11) ◽  
pp. 872-880 ◽  
Author(s):  
Jeong Hyuk Im ◽  
Y. Richard Kim

With an increasing emphasis on pavement preservation treatments due to economic concerns over the high costs of paving materials, one of the most cost-effective pavement preservation treatments, chip seals, now constitutes a significant proportion of the pavement preservation treatments used in the North Carolina highway network. To mitigate a major problem with chip seals, i.e., the loose aggregate particles, fog seals, which are composed of an emulsified product placed on top of the chip seal, can be used to help control the loose aggregate. For this study, fog seals were applied on top of newly fabricated chip. The surface texture of the fog-sealed chip seals was analyzed using the British pendulum test and a three-dimensional laser. Also, fog seal field test methods that were developed to suggest appropriate traffic opening times after fog seal construction were verified. The main findings presented in this paper are that: (i) the use of polymer-modified emulsions improves fog seal performance in terms of better aggregate retention and bleeding resistance; (ii) the skid resistance problems are not evident once the fog seal is applied on the recommended chip seal type; (iii) the relationship between skid number and mean profile depth can be determined based on three trends that are dependent on traffic loadings, and (iv) although the fog seal field tests were unable to be completed due to safety concerns, it can nonetheless be recommended that approximately 60 min after fog seal construction is an appropriate traffic opening time.


Author(s):  
Farhang Jalali ◽  
Adriana Vargas-Nordcbeck

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.


Author(s):  
Hui Li ◽  
John Harvey ◽  
Zhang Chen ◽  
Yuan He ◽  
Thomas J. Holland ◽  
...  

This paper summarizes the results of measurements of macrotexture on a set of California Department of Transportation (Caltrans) and local government pavement surface treatments and their correlation with survey results of bicycle vibration and ride quality on the same sections. The test sections that were used for the bicycle vibration and ride quality measurements included various surface treatments placed on an existing chip seal on SR-198 in Monterey County, a chip seal on SR-1 in San Luis Obispo County, and several other sections with various textures and roughness levels on other state highway and county road sections. Macrotexture was measured in mean profile depth (MPD). Three test methods were used to measure MPD: the sand patch, the laser texture scanner, and the inertial profiler. Presented are statistical correlations between macrotexture, roughness [according to the international roughness index (IRI)], bicycle vibration, and bicycle ride quality for the surveyed treatment sections. Conclusions are presented for MPD values measured on road sections with different treatment designs and for the variability of MPD found between sections built with the same chip seal aggregate grading. Correlations between bicycle vibration and MPD are presented, along with correlations between MPD, IRI, bicycle vibration, and bicyclists' perception of ride quality and pavement acceptability for bicycle use. This study's results can assist Caltrans and other road owners considering gradation when continuing to use the cost-effective chip seal treatment to preserve their pavements while maintaining a bicycle-friendly surface.


Author(s):  
Douglas D. Gransberg

A survey of U.S. public highway and road agencies that use chip seals as a part of their roadway maintenance program was developed and conducted to identify best practices in chip seal design and construction. A total of 72 individual responses from 42 U.S. states and 12 U.S. cities and counties were received; of those, nine respondents reported that they were getting excellent results from their chip seal programs. Those responses were grouped together and analyzed by the case study method to identify trends that lead to consistently excellent chip seal results. The study found that the successful chip seal programs had much in common. They use chip seals as a preventive maintenance tool, applying them to roads before distress levels were classified as moderate. They require their contractors to use the latest technology, and they exploit advances in material science such as the use of modified binders. And most of them use chip seals on both high- and low-volume roads.


Author(s):  
Adriana Vargas-Nordcbeck ◽  
Michael C. Vrtis ◽  
Benjamin Worel

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.


Author(s):  
Javon Adams ◽  
Mohammad Ilias ◽  
Cassie Castorena ◽  
Y. Richard Kim

This paper details the development of a framework for emulsion performance-grade (EPG) specifications for chip seal treatments. Chip seals are preservation surface treatments that are designed to improve the condition of the pavement surface while mitigating deterioration of the overall pavement structure. Asphalt emulsions used in chip seals often are selected based on factors that are not necessarily related to performance. Aggregate loss and bleeding have been identified as the most critical chip seal distresses that are related to binder performance. Storage stability, sprayability, and drain-out have been determined to be the most critical constructability concerns. For this study, binder and mixture test methods were identified to reflect the failure mechanisms for each critical distress type. The emulsion residue test methods that were identified to capture chip seal performance are the multiple stress creep and recovery test for bleeding and the dynamic shear rheometer frequency sweep test for low-temperature aggregate loss. The fresh emulsion test methods that were identified to capture chip seal constructability are the three-step shear test and storage stability test. The proposed EPG specifications for the fresh emulsion properties that are related to constructability were developed using statistical analysis of the binder test results. The proposed EPG specifications for the residual binder properties were developed by defining the temperature-independent relationships between the emulsion residue properties and mixture performance that correspond to each critical distress. Preliminary specification limits were then established based on the values of the binder properties that correspond to the critical mixture performance thresholds.


2010 ◽  
Vol 15 (2) ◽  
pp. 121-131 ◽  
Author(s):  
Remus Ilies ◽  
Timothy A. Judge ◽  
David T. Wagner

This paper focuses on explaining how individuals set goals on multiple performance episodes, in the context of performance feedback comparing their performance on each episode with their respective goal. The proposed model was tested through a longitudinal study of 493 university students’ actual goals and performance on business school exams. Results of a structural equation model supported the proposed conceptual model in which self-efficacy and emotional reactions to feedback mediate the relationship between feedback and subsequent goals. In addition, as expected, participants’ standing on a dispositional measure of behavioral inhibition influenced the strength of their emotional reactions to negative feedback.


2016 ◽  
Vol 6 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Kathleen Van Benthem ◽  
Chris M. Herdman

Abstract. Identifying pilot attributes associated with risk is important, especially in general aviation where pilot error is implicated in most accidents. This research examined the relationship of pilot age, expertise, and cognitive functioning to deviations from an ideal circuit trajectory. In all, 54 pilots, of varying age, flew a Cessna 172 simulator. Cognitive measures were obtained using the CogScreen-AE ( Kay, 1995 ). Older age and lower levels of expertise and cognitive functioning were associated with significantly greater flight path deviations. The relationship between age and performance was fully mediated by a cluster of cognitive factors: speed and working memory, visual attention, and cognitive flexibility. These findings add to the literature showing that age-related changes in cognition may impact pilot performance.


2016 ◽  
Vol 15 (2) ◽  
pp. 55-65 ◽  
Author(s):  
Lonneke Dubbelt ◽  
Sonja Rispens ◽  
Evangelia Demerouti

Abstract. Women have a minority position within science, technology, engineering, and mathematics and, consequently, are likely to face more adversities at work. This diary study takes a look at a facilitating factor for women’s research performance within academia: daily work engagement. We examined the moderating effect of gender on the relationship between two behaviors (i.e., daily networking and time control) and daily work engagement, as well as its effect on the relationship between daily work engagement and performance measures (i.e., number of publications). Results suggest that daily networking and time control cultivate men’s work engagement, but daily work engagement is beneficial for the number of publications of women. The findings highlight the importance of work engagement in facilitating the performance of women in minority positions.


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