[BUCH][B] Asphalt mixtures containing chemically modified binders

KD Stuart - 1993 - trid.trb.org
KD Stuart
1993trid.trb.org
The properties of a mixture containing an AC-20 control asphalt binder were compared with
those of mixtures in which the binder was modified with either 1.5% chromium trioxide
(CrO3), 6.0% maleic anhydride (MAH), or 0.75% furfural. Penetration and viscosity data of
binders recovered from the mixtures indicated that the three chemically modified binders
should be stiffer at high pavement temperatures and softer at low pavement temperatures
than the AC-20 control asphalt. The permanent strains from a creep test were used to …
The properties of a mixture containing an AC-20 control asphalt binder were compared with those of mixtures in which the binder was modified with either 1.5% chromium trioxide (CrO3), 6.0% maleic anhydride (MAH), or 0.75% furfural. Penetration and viscosity data of binders recovered from the mixtures indicated that the three chemically modified binders should be stiffer at high pavement temperatures and softer at low pavement temperatures than the AC-20 control asphalt. The permanent strains from a creep test were used to evaluate the susceptibilities of the mixtures to rutting. The three chemically modified binders decreased these strains by an average of 25%. However, this difference was not statistically significant because of the high variability of the test data. The three chemically modified binders provided improved low-temperature properties down to approximately-16 deg C (3.2 deg F) on the basis of diametral tests. All four mixtures showed equivalent data below this temperature. The MAH-modified mixture passed both engineering tests used to evaluate moisture susceptibility. The CrO3, furfural, and AC-20 control mixtures each failed at least one of the tests. The AC-20 control mixture had a high amount of visual stripping, whereas all three modified mixtures showed no visual stripping. It was concluded that the poor engineering test results shown by the CrO3-and furfural-modified mixtures were related to a loss of cohesion rather than a loss of adhesion. Except for the moisture susceptibility results, the three modified mixtures performed similarly.
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