DIGEST 2006 - Sabita

Figure 1. Figure 1. Bitumen grades sampled from 4 refineries for finger printing
testing was incorporated in the
project and is reported on.
Strategy
Fingerprint testing carried out at
Madison covered the following:
• Standard Dynamic Shear
Rheometer (DSR) testing on:
º Unaged binder (with
repeats);
º RTFOT aged;
º Pressure Ageing Vessel
(PAV) aged.
• Additional DSR testing on two
manufacturers of apparatuses
at:
º 0.1% strain versus 12%
strain;
º Different times of day
(temperature control).
• Bending Beam Rheometer
(BBR).
Standard DSR testing at 12%
strain (ε), according to SHRP
protocols, was carried out. In
addition, the Shear Modulus G*
versus Frequency was measured
at 0.5% ε for bitumen from four
SA refineries, as shown in Figure
2.
The DSR results show particularly
good agreement between the
measurements at different strain
levels, verifying that the 12% ε is
within the linear range of testing.
This verifies that SHRP’s reasoning
for adopting 12% ε as their
standard protocol is sound and
applicable to SA bitumen too.
The SHRP SuperPave Grading
System classifies a binder by
defining the average 7-day
maximum pavement design
temperature (ºC) as well as the
minimum pavement design
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