Details:

Creators:
Wang, Linbing, ; Druta, Cristian ; Lane, D. Stephen
Wang, Linbing, ; Druta, Cristian ; Lane, D. Stephen Less -
Corporate Creators:
Virginia Transportation Research Council (VTRC) ; Virginia. Dept. of Transportation ; United States. Federal Highway Administration
Virginia Transportation Research Council (VTRC) ; Virginia. Dept. of Transportation ; United States. Federal Highway Administration Less -
Subject/TRT Terms:
[+]
Aggregates Aggregates (Building Materials)--Testing--Virginia Carbonate Rocks Pavements Pavements--Skid Resistance--Virginia Polishing (Aggregates) Road Materials--Testing--Virginia Skid Resistance Texture
Publication/ Report Number:
VTRC 10-CR7 ; FHWA/VTRC 10-CR7
VTRC 10-CR7 ; FHWA/VTRC 10-CR7 Less -
Resource Type:
Tech Report
Geographical Coverage:
Virginia
Edition:
Final contract report.
Corporate Publisher:
Virginia Transportation Research Council (VTRC)
Abstract:
The predominant aggregate resources located in the western parts of Virginia are carbonate rocks. The mineral components of these rocks tend to be relatively soft and subject to abrasive wear under traffic that leads to a fairly rapid smoothing of the aggregate surface and the surface of pavements containing them. This smoothing or polishing leads to a loss of surface friction and thus skid resistance of the pavement, creating potential safety issues. As a consequence, surface courses of pavements are constructed with nonpolishing aggregates, which in the western districts can mean lengthy transport of materials. With rising economic and environmental costs associated with transportation, increasing the use of locally available materials through improved methods to discern subtle differences in polishing tendencies or blending of polishing with nonpolishing aggregates could translate into significant cost savings. In this study, a suite of carbonate aggregates suspected to show a range of polishing characteristics based on previous studies was selected for evaluation along with several sources currently used as nonpolishing aggregates. The aggregates were examined petrographically, and the carbonate sources were tested for insoluble residue and subjected to a dilute acid etch to form the basis for a tentative classification of polishing susceptibility. The aggregates were tested in the Micro-Deval apparatus using both the standard procedure for coarse aggregates and a cyclical A/P procedure with silica sand devised for this study to examine how the various aggregate types responded when subjected to various degrees of wearing under similar conditions. Following abrasion cycles, 2-D digital aggregate images were obtained and analyzed using specialized software to assess their morphological properties with emphasis on angularity and surface texture. These properties were assessed before and after abrasion to determine the degree and rate of change in surface texture as well as the texture distribution within an aggregate sample. In addition, pictures were taken of the exposed surfaces of three experimental pavement sections in the Virginia Department of Transportation's Bristol District containing carbonate rock as the fine aggregate blended with nonpolishing coarse aggregate to visually assess the effect of traffic in the last 3 years. The carbonate rocks evaluated could be grouped according to polishing and wear tendency based on petrographic characteristics and mass loss in the Micro-Deval tests. Although visual distinctions could be discerned, these differences were not identified statistically by the image analysis program, but factors affecting the program were identified. A second phase of work is proposed that focuses on developing an accelerated pavement wearing protocol for assessing polishing tendencies and evaluating various mixtures of carbonate and nonpolishing aggregates
Format:
PDF
Funding:
91337
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:a0fa069b24670b3b2aa554bce5f66f5f96dad3ec9891afb63e6b92f18adb8223
Download URL:
https://rosap.ntl.bts.gov/view/dot/20244/dot_20244_DS1.pdf
File Type:

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