Effect of Performance Warranties on Cost and Quality of Asphalt Pavements

2007 ◽  
Vol 2040 (1) ◽  
pp. 100-106 ◽  
Author(s):  
Scott Shuler ◽  
Tim Aschenbrener ◽  
Robert DeDios
Keyword(s):  
Asphalt Pavements

Performance Analysis of Ultrathin Whitetopping Intersections on US-169: Elk River, Minnesota

2003 ◽  
Vol 1823 (1) ◽  
pp. 18-27 ◽  
Author(s):  
Julie M. Vandenbossche
Keyword(s):  
Test Section ◽  
Hot Mix Asphalt ◽  
Asphalt Pavements ◽  
Department Of Transportation ◽  
Uniform Thickness ◽  
Research Facility ◽  
Transverse Cracks ◽  
Elk River ◽  
Joint Pattern

The Minnesota Department of Transportation constructed an ultrathin whitetopping (UTW) project at three consecutive intersections on US-169 at Elk River, Minnesota, to gain more experience with both the design and the performance of UTW. Distinct cracking patterns developed within each test section. The UTW test sections with a 1.2- ×1.2-m (4- ×4-ft) joint pattern included corner breaks and transverse cracks. Corner breaks were the primary distress in the test section with a 1.8- ×1.8-m (6- ×6-ft) joint pattern, although very little cracking was exhibited. The Minnesota Road Research Facility UTW test sections on I-94 allow comparisons of the same UTW design on hot-mix asphalt (HMA) pavements with different structural capacities to be made. The strain and deflection measurements emphasize the importance of the support provided by the HMA layer. A reduction in this support occurs when the temperature of the HMA is increased or when the HMA begins to ravel. During evaluations of whether UTW is a viable rehabilitation alternative, cores should be pulled from the pavement to determine if the asphalt is stripping and if the asphalt layer has adequate thickness. UTW can be successfully placed on as little as 76 mm (3 in.) of asphalt, if the quality of the asphalt is good. The cores should also reveal whether the asphalt layer is of uniform thickness and whether stripping and raveling have occurred. If the asphalt layer is of uniform thickness and stripping and raveling have not occurred, UTW is a good option for use in the rehabilitation of asphalt pavements.

Predictive quality of the pavement ME design program for field performance of warm mix asphalt pavements

2017 ◽  
Vol 131 ◽  
pp. 400-410 ◽  
Author(s):  
Weiguang Zhang ◽  
Shihui Shen ◽  
Ahmed Faheem ◽  
Prasanta Basak ◽  
Shenghua Wu ◽  
...  
Keyword(s):  
Field Performance ◽  
Warm Mix Asphalt ◽  
Asphalt Pavements ◽  
Predictive Quality ◽  
Design Program ◽  
Pavement Me Design

The Quality of Infiltrated Water Through Porous and Conventional Asphalt Pavements

2007 ◽  
Vol 8 (4) ◽  
pp. 617-641 ◽  
Author(s):  
M. Legret ◽  
V. Colandini ◽  
C. Pagotto ◽  
A. Jullien
Keyword(s):  
Asphalt Pavements

Hot In-Place Recycling of Asphalt Pavements: Oregon Experience

1996 ◽  
Vol 1545 (1) ◽  
pp. 113-119 ◽  
Author(s):  
David F. Rogge ◽  
Walter P. Hislop ◽  
Richard L. Dominick
Keyword(s):  
Design Procedure ◽  
Project Selection ◽  
Lessons Learned ◽  
Mix Design ◽  
Asphalt Pavements ◽  
Ride Quality ◽  
Department Of Transportation ◽  
Suitable Candidate

A study was carried out to evaluate the potential of using hot in-place recycling (HIR) as a rehabilitation alternative in Oregon. Data from six Oregon Department of Transportation HIR projects constructed in 1992–1993 were analyzed. The construction equipment, pavement properties, project selection, mix design, and resulting performance are summarized and presented. Only one HIR project was successful in rejuvenating the pavement and restoring ride quality. Of particular interest are the problems encountered in the other projects, which are discussed and show the importance of preliminary engineering and project selection for successful HIR. The lessons learned from the six projects are used as guidelines for selecting suitable candidate pavements for HIR. The results from the HIR projects combined with a literature review and limited laboratory testing led to a recommended HIR mix design procedure. Significant findings include the following: (a) HIR is a developing technology that shows promise for properly selected projects, (b) project selection is the most critical step in the HIR process, and (c) critical mix design inputs come from testing in situ pavement properties and laboratory specimens remolded with rejuvenating agent added.

Initial Ride Quality of Hot-Mix Asphalt Pavements

2005 ◽  
Vol 1907 (1) ◽  
pp. 104-112
Author(s):  
M. Stroup-Gardiner ◽  
Alan Carter ◽  
Thomas Das ◽  
Brian Bowman
Keyword(s):  
Hot Mix Asphalt ◽  
Asphalt Pavements ◽  
Ride Quality ◽  
Acceptance Testing ◽  
International Roughness Index ◽  
Wide Range ◽  
Key Issues ◽  
Lane County ◽  
Local Anomalies

Ride quality assessed with an inertial profiler on flexible pavement was used to provide initial information on the following key issues: repeatability associated with international roughness index (IRI) values for a wide range of hot-mix asphalt (HMA) material variables, timing of acceptance testing for initial ride quality, IRI changes with type of roadway, influence of stops and starts in the paving operation on ride quality, identification of “bump,” and effect of grinding on IRI. IRI was calculated for 25-ft intervals instead of the standard 0.1 mi (528 ft) for all testing to highlight local anomalies such as bumps due to paving stoppages. Results indicate that the standard deviation of three replicate passes with an inertial profiler is 5 in./mi (includes 46 HMA mixes on the Auburn University National Center for Asphalt Technology test track). IRI measurements with time suggest that initial acceptance testing can be conducted within 7 days, which allows more flexibility in scheduling by the agency. Limited traffic also slightly reduces the IRI values, which is to the contractor's advantage. IRI values are suggested for two-lane county roads and medium- to high-traffic facilities. Separate IRI ranges are indicated for each of these categories on the basis of the type of HMA construction: new, repair and overlay, and mill and overlay. These ranges are set for best and good practices (continuous paving, no stoppages; consistent supply of trucks, very short stops). IRI values greater than 125 in./mi in any given 25-ft interval indicate a bump; bumps can be ground so that these areas have IRI values of less than 100 in./mi.

Immunoferritin localization of intracellular antigens in positively stained frozen sections

1978 ◽  
Vol 36 (2) ◽  
pp. 168-169
Author(s):  
K. T. Tokuyasu
Keyword(s):  
Surface Tension ◽  
Water Surface ◽  
Thin Layers ◽  
The Other ◽  
Positive Staining ◽  
Frozen Sections ◽  
The Past ◽  
Ultrathin Frozen Sections ◽  
Definition Of

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).

Lithography below 100 nm

1983 ◽  
Vol 41 ◽  
pp. 96-99
Author(s):  
L. D. Jackel
Keyword(s):  
Spatial Distribution ◽  
Electron Beam ◽  
Electron Scattering ◽  
Electron Beam Lithography ◽  
Substrate Material ◽  
Local Electron ◽  
Electron Dose ◽  
Positive Resist ◽  
Exposure Process

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.

Convergent Beam Electron Diffraction

1978 ◽  
Vol 36 (3) ◽  
pp. 304-315
Author(s):  
G. Lehmpfuhl
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Crystal Surface ◽  
Diffraction Spot ◽  
Crystal Thickness ◽  
Large Area ◽  
Electron Microscopic ◽  
Additional Information ◽  
Microscopic Investigations

Introduction In electron microscopic investigations of crystalline specimens the direct observation of the electron diffraction pattern gives additional information about the specimen. The quality of this information depends on the quality of the crystals or the crystal area contributing to the diffraction pattern. By selected area diffraction in a conventional electron microscope, specimen areas as small as 1 µ in diameter can be investigated. It is well known that crystal areas of that size which must be thin enough (in the order of 1000 Å) for electron microscopic investigations are normally somewhat distorted by bending, or they are not homogeneous. Furthermore, the crystal surface is not well defined over such a large area. These are facts which cause reduction of information in the diffraction pattern. The intensity of a diffraction spot, for example, depends on the crystal thickness. If the thickness is not uniform over the investigated area, one observes an averaged intensity, so that the intensity distribution in the diffraction pattern cannot be used for an analysis unless additional information is available.

Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 26-27
Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Image Contrast ◽  
Objective Lens ◽  
Thick Specimen ◽  
Transmission Electron ◽  
Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

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