Determination of Creep Compliance and Tensile Strength of Hot-Mix ...

1.00Creep Compliance (1/GPa)0.1007-123 [BP-1]: PG64-22: 20% RAP (Dolomite)06-125 [SP125C]: PG64-22: (Limestone)06-105 [SP125C]: PG70-22: 10% RAP (Dolomite)06-150 [SP125C]: PG70-22: 10% RAP (Limestone)06-84 [SP125BSM]: PG76-22: (Porphry)06-101 [SP125B]: PG76-22: (Dolomite)0.011 10 100Time (sec)'06-84 06-101 06-125 06-150 07-123 06-105Figure 9: Creep Compliance Comparisons: 6.5% Voids, 0°CTwo rounds of IDT creep testing of the BP-1 (07-123) mix were performed becausethe first round of creep testing was performed with an insufficient load. The loadduring the first round of testing produced initial horizontal deformations that did notmeet the lower limit of ~33 microstrain. So, although six replicate specimens weretested for tensile strength, only the last 3 replicate specimens (round 2) were used tocalculate creep compliance.There were also two rounds of IDT creep testing on 06-84, the SMA mix. The firstround of testing resulted in creep compliance values for the 4% voids specimensthat were greater than the 6.5% voids specimens, backward from the expectedtrend. The non-uniform void distribution in the SMA specimens resulted in one faceof the sawn specimen sometimes possessing large exposed voids while theopposite face was much smoother. It is speculated that this difference in face texturecould have been the cause of the unexpected trend. The second round of creeptesting produced expected results and those values are the ones reported in Table5. There was not a second round of tensile strength testing immediately following thesecond round of creep testing.At 6.5% air voids and at all three test temperatures, 07-123 is the stiffest or leastcompliant of the six mixes investigated, whereas 06-125 is the most compliant. Thisresult dramatically shows the effect that RAP has on creep compliance. Both 07-123and 06-125 utilize PG64-22 as the virgin binder yet they are at the extremes, at least21