Details:

Creators:
Castorena, Cassie ; Fried, Andrew ; Malladi, Haritha
Castorena, Cassie ; Fried, Andrew ; Malladi, Haritha Less -
Corporate Creators:
North Carolina State University. Department of Civil, Construction, and Environmental Engineering
Corporate Contributors:
North Carolina Department of Transportation. Research and Development Unit
Subject/TRT Terms:
[+]
Absorption Application Rate Asphalt Emulsions Chip Seals Pavements Tack Coats
Publication/ Report Number:
FHWA/NC/2018-15
Resource Type:
Tech Report
Geographical Coverage:
United States
Edition:
Final Report, 8/1/2017-5/31/2021
Corporate Publisher:
North Carolina Department of Transportation. Research and Development Unit
Abstract:
The Emulsion Application Rate (EAR) is critical to the performance of both tack coats and chip seals. When emulsion is applied to an aged flexible pavement, a portion of the applied emulsion will be absorbed by the existing pavement. To compensate, the current practice is to adjust the required target EAR used in the construction based on visual inspection of the existing pavement surface, which is subjective. The objectives of this project are to: (1) determine the pavement emulsion absorption rate as a function of surface characteristics and (2) develop guidelines for the adjustment of the target EAR to account for emulsion absorption based on quantitative measurement of the existing pavement surface characteristics. Tack Lifter field experiments conducted on 13 pavements indicate that the absorbed EAR vary considerably depending on the existing pavement surface conditions. Statistical analysis of the field measurements acquired in this study indicate that the application (i.e., chip seal versus tack coat) and mean texture depth affect the resultant pavement emulsion absorption rate. A linear regression model was calibrated to predict the pavement emulsion absorption rate as a function of mean texture depth and application that yielded moderate prediction accuracy (R2 = 0.56). The moderate prediction capability indicates that other factors that were not captured by the application type and texture influence the emulsion absorption capacity of pavements but allows for an approximation of the absorbed EAR in cases where project-specific Tack Lifter testing cannot be conducted. Tack Lifter experiments conducted on field cores in the laboratory indicate that Colorimeter measurements of hue are moderately correlated to the pavement emulsion absorption rate (R2 = 0.42), which merits further investigation using field experiments in the future. Field core measurements of emulsion absorption rates indicated differences from field measurements of emulsion absorption rates with respect to sensitivity to the mean texture depth and mean values in tack coat applications. This could be due to differences in application procedures in the field versus the lab. Also, field measurements were made in the wheel path whereas field cores were extracted elsewhere.
Format:
PDF
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:52e611a1a6a77c575e22856027658f4c4047aec2149885fce61e5c49e483af68
Download URL:
https://rosap.ntl.bts.gov/view/dot/61233/dot_61233_DS1.pdf
File Type:

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