- Author
-
Knab, L. I.
|
Sprinkel, M. M.
|
Lane, O. J., Jr.
- Title
- Preliminary Performance Criteria for the Bond of Portland-Cement and Latex-Modified Concrete Overlays.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
Virginia Transportation Council, Charlottesville, VA
Iowa Department of Transportation, Ames
- Report
-
NISTIR 89-4156,
November 1989,
114 p.
- Keywords
-
cements
|
concretes
|
bond strnegth
|
bridge decks
|
direct shear bond test method
|
latex-modified concrete
|
overlay
|
pavement
|
performance criteria
|
precision
|
portland cement concrete
|
repair materials
- Abstract
- Preliminary bond-strength performance criteria were developed for screening and selecting portland-cement concrete (PCC) and latex-modified concrete (LMC) materials to be overlaid on PCC pavements and PCC bridge decks subjected to normal civilian truck and automobile traffic. The criteria were developed based on direct shear bond test results from (i) field cores from pavements and bridge decks which were considered to have performed satisfactorily, and (ii) laboratory- and field-cast specimens with PCC and LMC overlay materials. The criteria consist of minimum direct shear bond strength levels and corresponding minimum compressive strength levels. A direct shear "quillotine"-type performance bond test method, developed at the Brookhaven National Laboratories, was specified using laboratory-cast specimens. The criteria are preliminary because: (i) the criteria are based on very limited field- and laboratory-based bond strengths and should be further verified by being correlated with field performance, including various service conditions (temperature, moisture, wheel loading, etc)., (ii) the criteria need to be assessed with regard to repeatability within, and reproducibility among laboratories, (iii) the effects of material variables (aggregate, cement, mix design, etc.), surface preparation, placement procedures, curing conditions, and curing duration on the criteria need to be evaluated. Therefore, the criteria are a starting point and should be evaluated on a trial basis; most likely, the criteria will need to be modified as additional field performance results and laboratory experience are obtained. A notable limitation of the "guillotine" performance test method is its relatively poor precision, as evidencedby relatively large coefficient of variation values associated with the test method. Although the limitation of imprecision exists, the "guillotine" test method is still considered to be the best available performance bond test method for which field performance data exist. Field-performance data need to be obtained for other bond test methods with potentially better precision, such as the uniaxial tension test method, which was also investigated in the laboratory and reported in this report.