Details:

Creators:
Bennert, Thomas ; Maher, Ali
Bennert, Thomas ; Maher, Ali Less -
Corporate Creators:
New Jersey Department of Transportation
Corporate Contributors:
United States. Federal Highway Administration
Subject/TRT Terms:
[+]
Aggregates Aggregates (Building Materials)--New Jersey Base Course (Pavements) Concrete Pavements Pavements, Concrete--Recycling--New Jersey Recycling Roads--New Jersey--Base Courses Waste Products (Materials) Waste Products As Road Materials--New Jersey
Publication/ Report Number:
FHWA-NJ-2008-002
Resource Type:
Tech Report
Geographical Coverage:
New Jersey
Edition:
Final report; 1/2007-3/2008.
Corporate Publisher:
New Jersey. Dept. of Transportation
Abstract:
The research project was broken up into 2 different parts. The first part involved evaluating the potential use of the Time

Domain Reflectometry, TDR (ASTM D6780), as a non-nuclear means for determining the dry density and moisture content of

granular base and subbase aggregates during quality control. Just prior to the study, Humboldt Equipment Company provided

a device called the Electrical Density Gauge (EDG) that also claimed to be a non-nuclear means of determining dry density and

moisture content. Both units were used on five separate field trials (5 sections for the TDR and 3 sections for the EDG) and

compared against the NJDOT’s nuclear density gauge. The field trials indicated that the TDR test method, as it currently

stands according to ASTM D6780, does not compare well with the nuclear density gauge readings. This was mainly attributed

to the TDR’s soil constant calibration procedure. There also appeared to be a lack of sensitivity with the TDR method when

compared to the nuclear gauge. The EDG showed a better correlation to the nuclear gauge, although this was expected since

at the time of the study, the EDG device required field calibration. A newer version of the EDG now incorporates a laboratory

calibration procedure that would eliminate the need for field calibration with a nuclear gauge.

The second part of the research study was to evaluate potential methods of increasing the permeability of recycled concrete

aggregate (RCA), while attempting to maintain its structural integrity (i.e. – California Bearing Ratio, CBR). Before laboratory

testing began, a survey was developed, sent to various state agencies, and tabulated to determine if other state agencies

currently utilized RCA, and if so, what experience did they have regarding the drainage characteristics of the material. After the

survey results were tabulated, laboratory testing was conducted on RCA blended with different aggregates; dense-graded

aggregate (DGA), NJDOT I-3, and poorly graded sand. Work was also conducted on RCA material which was processed over

a coarser sieve size (2 inches), as opposed to the finer 1.5 inches currently specified by NJDOT, in an attempt to include a

larger, coarser fraction that could open up the internal structure of the RCA. This was in an attempt to meet some of the state

agency specifications of the various states who responded to the survey saying they did not have any current issues with the

permeability/drainage of their RCA materials. The results of the laboratory testing showed that the best performing

modification to the RCA was when blended with 50% DGA. This increased the permeability to levels considered average,

while still providing excellent bearing strength. The attempts of using the NJDOT I-3 and poorly graded sand did not

dramatically increase the permeability, while a decrease in bearing strength was still reported. Increasing the top size of the

processed/screened RCA from 1.5 inches to 2.0 inches helped to increase the permeability, while achieving the same bearing

strength properties (CBR).


Format:
PDF
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:afc852916860df0804661fb93a4dfca625934bc49c9432223058cc9b3f38d08c
Download URL:
https://rosap.ntl.bts.gov/view/dot/17162/dot_17162_DS1.pdf
File Type:

Supporting Files

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