Details:

Creators:
Shen, Junan ; Xie, Zhaoxing ; Li, Bo
Shen, Junan ; Xie, Zhaoxing ; Li, Bo Less -
Corporate Creators:
Georgia Southern University
Corporate Contributors:
United States. Federal Highway Administration
Subject/TRT Terms:
[+]
Asphalt Mixtures Bituminous Binders Crumb Rubber Dynamic Modulus Of Elasticity Evaluation Fatigue (Mechanics) Hot Mix Paving Mixtures Laboratory Tests Mix Design Pavement Performance Rutting Weathering
Publication/ Report Number:
FHWA-GA-12-1229
Resource Type:
Tech Report
Geographical Coverage:
Georgia
Corporate Publisher:
Georgia. Department of Transportation. Office of Research
Abstract:
This project investigated the long-term performance of hot asphalt mixes containing crumb rubber

modifiers (CRM) added in dry or wet processes. A total of eight asphalt mixtures—four Porous

European Mixtures (PEMs) and four Stone Matrix Asphalts (SMAs)—were designed with PG 76-22

modified with CRM, which was added in either a dry or wet process. These mixtures were compared to

control mixtures using an SBS-modified PG 76-22. Mixtures incorporating a “hybrid”-modified PG

76-22 were also evaluated. First, the samples were weathered in the Georgia Weathering Asphalt Device

(GWAD) for 1,000 hrs and 3,000 hrs and tested to determine their dynamic modulus, fatigue life,

rutting, and Cantabro. Binders extracted from the weathered samples were then evaluated using a

dynamic shear rheometer (DSR), gel-permeable chromatography (GPC), and Fourier transform infrared

spectroscopy (FTIR). Second, the interactions of dry- and wet-processed CRM with asphalt binder were

compared during storage and paving. Results indicated: 1) adding TOR to the CRM binder improved

PG grade and separation resistance; 2) the dynamic modulus, |E*|, of both rubberized PEM and SMA in

dry process did not differ significantly from that of the control mixtures or mixtures using the “hybrid”-

modified binders before and after weathering; 3) the fatigue life (Nf) of unaged rubberized PEM and

SMA in the dry process was similar to that in wet process, although lower than that of control SBS; 4)

after 3000-hrs aging, the fatigue life of the dry-processed rubberized SMA is similar to that of the

wet-processed but lower than that of hybrid and SBS SMA, regardless of strain and stress levels or test

temperatures; 5) the rutting and Cantabro loss of the rubberized PEM and SMA in dry process were

higher than those of control SBS after weathering; 6) CRM and asphalt binder interact during the

production and paving stages based on DSR, GPC, FTIR, and AFM results. The effect of weathering on

the properties of the asphalt binders in rubberized, dry-processed PEMs and SMAs was similar to that in

the wet-processed mixtures but greater than that in the control SBS.


Format:
PDF
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:e7cf65ed37de184bd21cac2080d9f48a02086c27ab5a6a10bae9830691ab9d28
Download URL:
https://rosap.ntl.bts.gov/view/dot/29368/dot_29368_DS1.pdf
File Type:

Supporting Files

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