Search Results (2)

Expansion relief groove (ERG) controlling excess arch expansion has become a research hotspot. Based on statistical arch expansion data, this paper proposes a novel structural design for ERG, selecting asphalt-treated base (ATB-25) and graded gravel (GG) as fill materials for trial paving. Through three years of monitoring, the temperature, stress, and displacement across the two solutions were comparatively analyzed to evaluate their control effectiveness. The results indicated five points. (1) The reasonable spacing of the expansion through should be 200 m, and the width should not be less than 50 cm in ERG structure design. (2) The annual temperature difference of ATB-25 ERG (55 °C) > GG ERG (51 °C) > cement-treated base (CTB) (47 °C). The large annual temperature difference causes the expansion of the base. (3) The performance of ERGs is highly correlated with the seasonal alternation. The compressive stress increases in summer, resulting in compressive deformation, and decreases in winter, resulting in extended deformation. (4) According to three years of monitoring, the plastic deformation accumulated, and the compression deformation in the two ERGs increased to 155% and 943.47% of that in the first year. The expansion pressure in the base layer is constrained, resulting in compression deformation of the base. (5) GG is more suitable as the filler of the ERG to deal with arch expansion disease and demonstrates excellent cost-effectiveness. Full article

In this study, the performance of the fiber-reinforced, stress-absorbing membrane interlayer (F-SAMI) method was evaluated to suppress reflective cracks, which usually occur when the overlay method is applied for the maintenance of existing aged pavement. The F-SAMI method has an effect of suppressing the occurrence of reflective cracks by constructing a material composed of emulsified asphalt, fibers, and aggregates between the surface layer and the base layer. The mechanical performance of the F-SAMI was evaluated through both small-scale (model mobile load simulator 3, or MMLS3) and large-scale (accelerated pavement testing, or APT) pavement acceleration tests on the specimen and pavement structures, respectively, with the F-SAMI layer applied between the surface layer and the base layer. In this study, the base layer was made with an asphalt mixture or a concrete mixture, and the surface layer was made with polymer-modified stone mastic asphalt (PSMA). Evaluation was conducted by applying four types of F-SAMI layer, according to the content of asphalt and aggregate and compared with the case where general tack coating was applied. In order to induce the occurrence of reflective cracks, a notch was made in the center of the base layer. As a result of the experiment, it was shown that regardless of the mixture type of the base layer, the specimen or pavement with the F-SAMI method was much more resistant to reflective cracking than those with the tack coating. In addition, it was found that the F-SAMI method with aggregates was more resistant to reflective cracks than that without aggregates. Full article