Field Verification of Proposed Changes to the AASHTO R 30 Procedures for Laboratory Conditioning of Asphalt Mixtures (2019) / Chapter Skim
Currently Skimming:
Pages 3-8
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 3... ...
3 Introduction Background Asphalt pavements are subject to rheological changes in the form of stiffening over time in response to oxidation. As asphalt mixtures are produced in plants, they are subjected to heat and air during mixing and storage.
|
From page 4... ...
4 Previous Research -- NCHRP Project 09-52 For NCHRP Project 09-52, the focus was to (a) develop a laboratory short-term aging protocol to simulate the aging and asphalt absorption of an asphalt mixture during production and transportation, and (b)
|
From page 5... ...
5 CDD values for post-construction cores tested and presented in NCHRP Report 815 (Newcomb et al.
|
From page 6... ...
6 After short-term aging during production and construction, asphalt pavements age at a continually slower rate throughout their in-service life. The changes resulting from field aging in asphalt mixture properties should be accounted for with performance testing after LTOA.
|
From page 7... ...
7 Reference Short-Term Aging Major Finding Heithaus and Johnson 1958 Field Aging Most aging during production and construction through compactionTraxler 1961 Chipperfield and Welch 1967 West et al. 2014 • WMA less aging than HMA during production • Reduced difference between WMA and HMA with field aging • Equivalent binder true grade and binder absorption for WMA versus HMA after 2 years of field aging Traxler 1961 Factor on Field Aging Binder chemistry and aggregate absorption major effects Chipperfield and Welch 1967 Aggregate gradation no effect Lund and Wilson 1984 and 1986 Binder type and binder source significant effects Mogawer et al.
|
From page 8... ...
8 a laboratory STOA protocol of 4 hours at 275°F (135°C) was representative of the short-term aging that usually occurs at production and construction.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.