Performance-based analysis of polymer-modified emulsions in asphalt surface treatments : final report - Page 106 |
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5. However, polymer modification improves the aggregate retention performance of double
seals, even though the aggregate in the top layer is the lightweight aggregate. It seems
that the uniform gradation of the lightweight aggregate does not contribute to improved
aggregate retention performance in the double seals because the combined aggregate
structure created by the non-uniform granite 78M aggregate in the bottom layer and the
uniform lightweight aggregate in the top layer reduces the beneficial effects of the
uniform gradation in the lightweight aggregate and, thus, enhances the beneficial effects
of polymer modification.
6. Based on the results from bleeding performance tests and visual observation, PME is
recommended to improve bleeding resistance regardless of chip seal type. The bleeding
caused by excess binder does not occur, regardless of chip seal type, in this study because
the EAR used in this study is close to the optimal rate. The bleeding performance of the
double seal is significantly different because the unmodified emulsion in the double seals
shows evidence of bleeding due to aggregate loss, thus indicating a significant
relationship between aggregate loss and bleeding. Nonetheless, the PME chip seal does
not exhibit bleeding after four hours.
7. Polymer modification enhances both resistance to rutting development and aggregate
retention performance. PME shows significant rutting resistance against traffic loading.
Specifically, PME provides rutting resistance at high temperatures.
8. LCCA shows PME to be cost effective on condition that the service life of the PME is
two years longer than that of an unmodified chip seal, despite the fact that PME typically
costs about 30% more than unmodified emulsion. The performance data obtained from
this study, including aggregate loss, bleeding, and rutting, indicate that the use of PMEs
can extend the service life of chip seals more than two years, thus justifying the cost
effectiveness of using PMEs in chip seals.
The main recommendation for future research is to optimize the construction procedure
(including the rolling pattern and traffic closure time) for polymer-modified chip seals to
maximize the benefits of using PME. This report clearly demonstrates that polymer-modified
chip seals behave quite differently than unmodified chip seals. Therefore, the construction
procedure used for unmodified chip seals will not yield the best performance if applied to
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| Title | Performance-based analysis of polymer-modified emulsions in asphalt surface treatments : final report - Page 106 |
| Full Text | 97 5. However, polymer modification improves the aggregate retention performance of double seals, even though the aggregate in the top layer is the lightweight aggregate. It seems that the uniform gradation of the lightweight aggregate does not contribute to improved aggregate retention performance in the double seals because the combined aggregate structure created by the non-uniform granite 78M aggregate in the bottom layer and the uniform lightweight aggregate in the top layer reduces the beneficial effects of the uniform gradation in the lightweight aggregate and, thus, enhances the beneficial effects of polymer modification. 6. Based on the results from bleeding performance tests and visual observation, PME is recommended to improve bleeding resistance regardless of chip seal type. The bleeding caused by excess binder does not occur, regardless of chip seal type, in this study because the EAR used in this study is close to the optimal rate. The bleeding performance of the double seal is significantly different because the unmodified emulsion in the double seals shows evidence of bleeding due to aggregate loss, thus indicating a significant relationship between aggregate loss and bleeding. Nonetheless, the PME chip seal does not exhibit bleeding after four hours. 7. Polymer modification enhances both resistance to rutting development and aggregate retention performance. PME shows significant rutting resistance against traffic loading. Specifically, PME provides rutting resistance at high temperatures. 8. LCCA shows PME to be cost effective on condition that the service life of the PME is two years longer than that of an unmodified chip seal, despite the fact that PME typically costs about 30% more than unmodified emulsion. The performance data obtained from this study, including aggregate loss, bleeding, and rutting, indicate that the use of PMEs can extend the service life of chip seals more than two years, thus justifying the cost effectiveness of using PMEs in chip seals. The main recommendation for future research is to optimize the construction procedure (including the rolling pattern and traffic closure time) for polymer-modified chip seals to maximize the benefits of using PME. This report clearly demonstrates that polymer-modified chip seals behave quite differently than unmodified chip seals. Therefore, the construction procedure used for unmodified chip seals will not yield the best performance if applied to |
