Utilization of Accelerated Pavement Tester (APT) for New Materials and Pavement Structure Research
-
2022-05-30
Details:
-
Creators:
-
Corporate Creators:
-
Corporate Contributors:
-
Subject/TRT Terms:
-
Publication/ Report Number:
-
Resource Type:
-
Geographical Coverage:
-
Edition:Final report January 2019 - May 2022
-
Corporate Publisher:
-
Abstract:Accelerated pavement test (APT) is defined as the controlled application of a prototype wheel loading at the appropriate load to the full-scale pavement structure, which is used to determine the structural responses and performance of the pavement in a short period. Inverted pavement is an unconventional type of flexible pavement structure. In this pavement structure, an unbound aggregate base (UAB) with a low initial modulus is layered between two stiffer layers, an asphalt concrete layer (AC) and a cement-treated base layer (CTB). This project presents two rounds of APT tests on full-scale inverted pavements. In the first-round APT, a comparison study on the rutting performance between the conventional and inverted pavement structures was presented. In addition, the inverted pavements with different thicknesses of UAB and CTB were studied. Significant permanent deflections were observed in all three pavement lanes after 100k passes of APT. Based on the measured deformation, the inverted pavement structure outperformed the conventional pavement in terms of the final surface deformation. And the inverted pavement with a thicker CTB layer had a better performance than the inverted pavement with a thicker UAB layer. Based on the overall pavement conditions, the inverted pavement can be regarded as an alternative to the conventional flexible pavement, and asphalt mixture layer thickness can be reduced during construction. In the second round of APT, the effect of geogrids in the inverted pavement was investigated. The polypropylene geogrids were installed in the full-scale inverted pavements and different locations of geogrids were discussed as well. After 150k passes of APT, the rutting performance was compared and studied. The results show that the geogrids could improve the rutting resistance of the inverted pavement, but the effect of geogrids depended on the location in the UAB layer. In this study, the geogrids placed at the upper 1/3 upper layer of UAB displayed the best rutting performance among the three pavement lanes due to its constraint for the aggregates. However, when the geogrids were installed at the 2/3 thickness of the UAB, the rutting performance of the inverted pavement structure became worse since its position experienced little tension and could not take effect. Therefore, the location of geogrids plays a vital role in improving the rutting resistance of the inverted pavement.
-
Format:
-
Funding:
-
Collection(s):
-
Main Document Checksum:
-
File Type:
Supporting Files
-
No Additional Files
More +