Details:

Creators:
Watson, Don ; Brown, E. Ray
Watson, Don ; Brown, E. Ray Less -
Corporate Creators:
Auburn University. National Center for Asphalt Technology
Corporate Contributors:
Florida. Dept. of Transportation
Subject/TRT Terms:
[+]
Asphalt Mixtures Contractors Evaluation Sampling Specifications Surveys
Publication/ Report Number:
PR6535008
Resource Type:
Tech Report
Geographical Coverage:
Florida
Corporate Publisher:
Auburn University. National Center for Asphalt Technology
Abstract:
The Florida Department of Transportation (FDOT) has traditionally required that all sampling

and testing of asphalt mixtures be at the Contractor’s production facility. With recent staffing cuts, as

well as budget reductions, FDOT has been considering alternative sampling methods which will

provide greater staffing flexibility, while at the same time provide assurance that a quality product is

placed on the roadway. One of the methods being considered is sampling the asphalt mixture at the

roadway.

The first objective of this study was to conduct a literature review and survey which included

interviewing various transportation engineers to determine which agencies require, or allow, field

sampling for acceptance and whether those efforts have been successful. The second objective of this

study was to evaluate the sampling and testing variability of samples taken at the plant compared to

those taken from the roadway mat and from the paver auger. A statistical evaluation was performed

to compare results from this study to the specification limits currently being used. Superpave 9.5 mm

and 12.5 mm mixes were sampled on 11 dense-graded projects, and two FC-5 projects (Open-Graded

mix) were sampled and tested.

The survey showed as many agencies require sampling from the roadway as require sampling

from the plant; but when agencies allow either location, samples are most often taken from a loaded

truck at the plant. When roadway samples are taken, most often those samples are taken from the

mat behind the paver.

For dense-graded mixes, individual test tolerances for air voids, and Gmm and Gmb values of

limestone mixes will need to be increased if roadway samples are to be used for acceptance or

comparison with contractor results. The differences for percent passing the No. 200 sieve were

statistically significant for auger samples, but deviations were within current tolerances. Asphalt

content was significantly affected by roadway mat samples, but deviations were within current

tolerances. Roadway samples of FC-5 mix from both the mat and auger were statistically different

than the contractor and FDOT samples taken at the plant. Roadway sampling is not recommended for

FC-5 mixes.


Format:
PDF
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:555f9f68e317c752c23b798aff89df19c73b2607b484e709d0fa1ed8e3bb4210
Download URL:
https://rosap.ntl.bts.gov/view/dot/28434/dot_28434_DS1.pdf
File Type:

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