Details:

Creators:
Kim, Yong-Rak ; Souza, Leonardo T.
Kim, Yong-Rak ; Souza, Leonardo T. Less -
Corporate Creators:
University of Nebraska--Lincoln. Dept. of Civil Engineering
Subject/TRT Terms:
[+]
Aggregates Angularity Asphalt Mixtures Asphalt Pavements Bituminous Mixtures Mechanical Tests Pavement Performance Performance Tests
Publication/ Report Number:
MPM-10
Resource Type:
Tech Report
Geographical Coverage:
United States
Corporate Publisher:
Nebraska Transportation Center
NTL Classification:
NTL-HIGHWAY/ROAD TRANSPORTATION-Pavement Management and Performance;NTL-HIGHWAY/ROAD TRANSPORTATION-Materials;
Abstract:
This research targeted two primary purposes: to estimate current aggregate angularity test methods and to evaluate current

aggregate angularity requirements in the Nebraska asphalt mixture/pavement specification. To meet the first research

objective, various aggregate angularity tests were estimated with the same sets of aggregates and were compared by

investigating their characteristics on testing repeatability, cost, testing time, workability, and sensitivity of test results. For

the second objective, the effect of aggregate angularity on mixture performance was investigated by conducting

laboratory performance tests (the uniaxial static creep test and the indirect tensile fracture energy test) of five mixes

designed with different combinations of coarse and fine aggregate angularity, and statistical analyses of five-year asphalt

pavement analyzer test results of field mixtures. Results from the indirect tensile fracture energy test were then

incorporated with finite element simulations of virtual specimens, which attempted to explore the detailed mechanisms of

cracking related to the aggregate angularity. Results from the estimation of various angularity test methods implied that

for the coarse aggregate angularity measurement, the AASHTO T326 method was an improvement over the current

Superpave method, ASTM D5821, in that it was more objective and was very simple to perform with much less testing

time. For the fine aggregate angularity measurement, the current Superpave testing method, AASHTO T304, was

considered reasonable in a practical sense. Rutting performance test results indicated that higher angularity in the mixture

improved rut resistance due to better aggregate interlocking. The overall effect of angularity on the mixtures’ resistance to

fatigue damage was positive because aggregate blends with higher angularity require more binder to meet mix design

criteria, which mitigates cracking due to increased viscoelastic energy dissipation from the binder, while angular particles

produce a higher stress concentration that results in potential cracks. Finite element simulations of virtual specimens

supported findings from experimental tests. Outcomes from this research are expected to potentially improve current

Nebraska asphalt specifications, particularly for aggregate angularity requirements and test methods to characterize local

aggregate angularity.


Format:
PDF
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:40c3a02bd1509304fab23523cd84d150ddcb9b01ace868c68c7ce864175cc215
Download URL:
https://rosap.ntl.bts.gov/view/dot/25454/dot_25454_DS1.pdf
File Type:

Supporting Files

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