Evaluation of MSCR Testing for Adoption in ADOT Asphalt Binder Specifications
-
2019-08-01
-
Details:
-
Creators:
-
Corporate Creators:
-
Corporate Contributors:
-
Subject/TRT Terms:
-
Publication/ Report Number:
-
Resource Type:
-
Geographical Coverage:
-
Edition:Final Report
-
Corporate Publisher:
-
Abstract:The purpose of this study is to recommend whether ADOT should consider adopting AASHTO T 350, Standard Method of Test for Multiple Stress Creep Recovery (MSCR) Test of Asphalt Binder Using a Dynamic Shear Rheometer (DSR), and AASHTO M 332,Standard Specification for Performance-Graded Asphalt Binder Using Multiple Stress Creep Recovery (MSCR) Test. The methods used in this study include a survey of the literature, interviews with personnel from other state DOTs, and laboratory experiments on asphalt binder and asphalt mixtures used by ADOT. The asphalt binder experiments include those currently called for by ADOT specifications and by AASHTO T 350. Asphalt mixture experiments include tests for the dynamic modulus as well as for fatigue and rutting resistance. The results of these experiments are compared to determine whether the AASTHO T 350 test is a better predictor of asphalt mixture performance than the tests currently used. The study finds that the AASHTO T 350 test parameter, nonrecoverable creep compliance, Jnr, is a better indicator of rutting than |G*|/sin δ. (|G*| is the dynamic shear modulus and δ is the material phase angle, both of which are measured as part of current ADOT specifications.) The study also finds that the recovery value, %R, from the AASHTO T 350 test can discern between asphalt binder with and without polymer-modification. Finally, the study finds that polymer-modified asphalt mixtures exhibit substantially better fatigue performance than do non-polymer-modified mixtures, and that the %R can also capture this increased performance. The primary conclusions from this study are that (1) the Jnr value is a better indicator of rutting performance for ADOT materials than |G*|/sin δ; (2) polymer-modified binders provide a greater fatigue life for ADOT materials than do non-polymer-modified binders; and (3) the %R parameter is not an indicator of rutting resistance, but it can distinguish between materials with better or worse fatigue performance.
-
Format:
-
Funding:
-
Collection(s):
-
Main Document Checksum:
-
Download URL:
-
File Type: