Many attempts have been made to simulate road aging with laboratory tests. These have generally not been successful. One reason is that other causes of road failure, such as heavy traffic or construction deficiency, can obscure the effect of the asphalt binder. But other reasons are that an adequate model relating laboratory-measured properties to changes in the road is not available and that the oventest temperatures that have been used may be too high to relate oven aging to road aging. Use of the lower-temperature pressure oxygen vessel offers promise of approximating road conditions. It is shown that no test run at a single elevated temperature can be used to simulate road aging and that at road temperature the rate is still too low for practical testing. It is also shown, however, that the oxidative aging mechanism is constant at temperatures up to 82.2 degrees C and that it approximates aging of the asphalt binder in laboratorycores. If this is borne out with road cores, extrapolation of higher temperature data may provide more accurate predictions of road aging. (A)
Samenvatting