Performance evaluation of fog seals on chip seals and verification of fog seal field tests

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.

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.


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.


2020 ◽  
Vol 12 (11) ◽  
pp. 1880
Author(s):  
Stefano Furlani ◽  
Valeria Vaccher ◽  
Vanja Macovaz ◽  
Stefano Devoto

The photogrammetric method is widely used in coastal areas and in submerged environments. Time-lapse images collected with unmanned aerial vehicles are used to reproduce the emerged areas, while images taken by divers are used to reproduce submerged ones. Conversely, 3D models of natural or human-made objects lying at the water level are severely affected by the difference in refractive index between air and seawater. For this reason, the matching of 3D models of emergent and submerged coasts has been very rarely tested and never used in Earth Sciences. The availability of a large number of time-lapse images, collected at the intertidal zone during previous snorkel surveys, encouraged us to test the merging of 3D models of emerged and submerged environments. Considering the rapid and effective nature of the aforementioned program of swim surveys, photogrammetric targets were not used during image acquisition. This forced us to test the matching of the independent models by recognizing prominent landforms along the waterline. Here we present the approach used to test the method, the instrumentation used for the field tests, and the setting of cameras fixed to a specially built aluminum support console and discuss both its advantages and its limits compared to UAVs. 3D models of sea cliffs were generated by applying structure-from-motion (SfM) photogrammetry. Horizontal time-lapse images, collected with action cameras while swimming parallel to the coastline at nearly constant velocity, were used for the tests. Subsequently, prominent coastal landforms were used to couple the independent models obtained from the emergent and submerged cliffs. The method was pilot tested in two coastal sites in the north-eastern Adriatic (part of the Mediterranean basin). The first site was a 25 m sea wall of sandstone set within a small harbor, while the second site was a 150 m route below plunging limestone cliffs. The data show that inexpensive action cameras provide a sufficient resolution to support and integrate geomorphological field surveys along rocky coastlines.


Author(s):  
Cameron Grile ◽  
Katharine M. Hunter-Zaworski ◽  
Christopher M. Monsere

As part of the project planning process, highway agencies must allocate limited funding to a substantial list of projects that exceeds available resources. For preservation projects, a key component of this decision is to determine which projects receive safety improvements and which are “pave only.” Traditionally, this decision has been made project by project, with the possible result of a selection that does not maximize safety benefits. This paper takes a case study approach and applies a new tool developed in NCHRP Report 486, the Resurfacing Safety Resource Allocation Program (RSRAP), to a subset of the Oregon Department of Transportation's (DOT's) highway network. The RSRAP tool maximizes safety improvements for a given set of projects and budget. Thirty-three projects scheduled to receive a new road surface were selected and analyzed with RSRAP. These projects were subdivided into smaller sites to meet the assumptions of RSRAP. Road geometry, traffic volumes, and crash history for each site were collected and input into the program. The type and cost of the safety improvements output by RSRAP were compared with those selected by Oregon DOT. This research determined that RSRAP, which selected more projects for safety improvements than did Oregon DOT, is a tool that could be used by the department to select various safety improvements on pavement preservation projects. It was also determined that the budget used by Oregon DOT was large enough that all cost-effective improvements could be made.


Author(s):  
Jia-Ruey Chang ◽  
Dar-Hao Chen ◽  
Ching-Tsung Hung

Although the cost-effectiveness of preventive maintenance (PM) treatments for pavement is important, literature addressing this issue is limited. Even under the well-controlled FHWA long-term pavement performance (LTPP) study, incomplete data and sections exist. Criteria for selecting PM treatments often conflict and have to be compromised. The multiple criteria decision-making (MCDM) method is one of numerous approaches available for resolving variations of results. The technique for order preference by similarity to ideal solution (TOPSIS), an MCDM method, was used to analyze successfully all 14 specific pavement study (SPS)-3 sites in Texas. The distress score (DS), international roughness index (IRI), and treatment costs were used as criteria to determine the cost-effectiveness of various PM treatments (thin overlay, slurry seal, crack seal, and chip seal). With TOPSIS, the cost-effectiveness of these treatments can be quantified, with variations caused by subjective judgment thus minimized. When all criteria were considered, the most and least cost-effective methods were chip seal and slurry seal, respectively. When cost was not considered, the most and least effective methods were chip seal and crack seal, respectively. The chip seals performed the best. Chip seals had the most forgiving qualities of all the methods, and they yielded no reflection of the cracking that preceded the treatment applications. The evaluation based on TOPSIS provides a viable option for engineers determining the best PM treatments for pavement in need of maintenance.


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.


2021 ◽  
pp. 002199832110092
Author(s):  
Daniel A Drake ◽  
Rani W Sullivan ◽  
Andrew E Lovejoy ◽  
Stephen B Clay ◽  
Dawn C Jegley

Fiber-reinforced polymer composites are widely used in the aerospace industry due to their high stiffness and strength-to-weight ratios. However, their applicability can be limited by their relatively low interlaminar properties when compared to metallic alternatives. Through-thickness reinforcement approaches, such as stitching, z-pinning, needling, tufting, and three-dimensional weaving, have been developed in recent decades to enhance the interlaminar properties of composites. Stitching is considered to be an efficient and cost-effective method to reinforce composites in the through-thickness direction. Additionally, stitch parameters (stitch density, linear thread density, thread material, pretension, etc.) highly influence the in-plane and out-of-plane properties. This paper summarizes results from over one hundred papers on the influence of stitch parameters on fracture energy, interlaminar strength, and impact characteristics of stitched composite laminates, sandwich composites, and high-temperature composites. Much of the research on the influence of stitch parameters has focused on thermoset polymer matrix composites (PMCs), while fewer studies have investigated the impact of stitch parameters on high temperature or sandwich composites. Modification of existing and new test methods have been developed to adequately measure the effectiveness of stitching on the out-of-plane behavior of PMC panels. Results demonstrate that out-of-plane properties of PMCs are highly dependent on stitch parameters and can be enhanced by through-thickness stitching.


Author(s):  
Gerrit J Jordaan ◽  
Wynand J VdM Steyn ◽  
Andre Broekman

Emulsion stabilisation of base layers surfaced with chip seals often proves problematic with chips punching into the base and early distress. This can be aggravated by the use of modified binders that restricts the evaporation of moisture from pavement layers. The introduction of New-age (Nano) Modified Emulsion (NME) stabilisation has the advantage that water is chemically repelled from the stabilised layer resulting in an accelerated development of strength. A need was identified to evaluate the early life performance of selected chip seals, together with identified binders. Three different chip seal surfacings with unconventional modified binders were constructed and evaluated using Accelerated Pavement Testing (APT) with the MMLS3. The objectives of the experimental design and testing were to evaluate binder performance, early loss of chips before chip orientation at low temperatures, punching of the chips into the NME stabilised base, deformation characteristics of a Cape seal and the effect of the use of a standard normal modified binder. This paper contains details of the NME base layer, the binder and seal selection and the test results. It is shown that a cost-effective thin chip seal in combination with a suitable binder can be used on a NME stabilised base with confidence.


2021 ◽  
Vol 342 ◽  
pp. 02008
Author(s):  
Ábel Dániel Antonovits ◽  
József Molnár

Underground coal mining was finished in the north-eastern region of Hungary after its operation of more than two centuries, as a result of economic, technical, environmental and political reasons. A fairly significant part of the reserve is still available to extract. With a different perspective of coal mining, considering different ways of utilization (such as coal chemistry, etc.) the extraction of the material can still be cost effective. In the past few years, several studies were conducted regarding the possible utilization of the available reserve. The properties of the coal are highly mutable, therefore, comprehensive knowledge about the geology is indispensable. Two and three-dimensional modelling of the coal seam is discussed in this paper, with the optimal coal face height, and the expected quality of mining products taken into consideration. Applying the method presented, the production can fulfil the desired properties, regarding to the utilization of the coal.


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