The use of recycled concrete aggregate in a dense graded aggregate base course.

Details

• Creators:
  Bennert, Thomas ; Maher, Ali
• Corporate Creators:
  New Jersey Department of Transportation
• Corporate Contributors:
  United States. Federal Highway Administration
• Subject/TRT Terms:
  • Aggregates
  • Base course (Pavements)
  • Concrete pavements
  • Recycling
  • Waste products (Materials)
  • Aggregates (Building materials)--New Jersey
  • Roads--New Jersey--Base courses
  • Pavements, Concrete--Recycling--New Jersey
  • 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 A newer version of the EDG now incorporates a laboratory ; calibration procedure that would eliminate the need for field calibration with a nuclear gauge.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).
  More +
• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/17162/dot_17162_DS1.pdf
• File Type:
  [PDF - 791.08 KB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:afc852916860df0804661fb93a4dfca625934bc49c9432223058cc9b3f38d08c