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This paper presents a stress-history-based approach to predict the deformation basins of airport pavements subjected to heavy aircraft loading applied in sequential wanders. Multi-depth deflectometer data from full-scale aircraft landing gear tests conducted at the National Airport Pavement Test Facility built by the Federal Aviation Administration are used to create individual pass residual deformation transverse profiles. The computed residual deformation profiles are further corrected for stress-history effects to predict rut in the selected test sections. The developed model focuses on using the previous load location and stress history of the soil element to develop the deformations in that element. Despite the unavailability of the surface transverse profile data measured in the field at different passes, the initial attempt of the model can closely predict the deformation profile similar to width and shape expected in the field. And after the stress-history effects are accounted for, the initially calculated rut depth decreases significantly to match the final contour basin of the test sections extracted from the post traffic trenching. The advantage of using the stress-history-effects-based rut prediction tool is that it can allow any combination of wander positions and sequences of load applications to be accounted for their effects on the final surface rut development.

Identifying the appropriate overlay thicknesses is critical to a local transportation agency's ability to maintain its pavement network. Local agencies often use empirical approaches for designing the overlay thickness for low-volume pavements. For example, overlay design for low-volume roads in Illinois is currently carried out using assumed layer coefficients for a limited number of material types. Although such empirical approaches are fairly simple to use, they are often not suitable for considering the effects of recycled and nontraditional construction materials that are more commonly considered in current-day sustainable pavement applications. The lack of mechanical testing for evaluating the pavement structural condition often leads to uneconomical practices in the rehabilitation of low-volume roads. This paper presents a mechanistic–empirical approach for overlay thickness designs of low-volume pavements through a combination of nondestructive deflection testing and preestablished pavement damage models. Five pavement sections, with varying structural and traffic characteristics, were selected from two counties in Illinois. Three sets of falling weight deflectometer tests were conducted over a period of one year to monitor changes in pavement deflection responses. Structural conditions of the pavement sections in their original configuration were evaluated first. Then, the corresponding required overlay thicknesses were determined by using two methods currently used by local agencies. The inability of the currently available methods to properly account for current pavement structural conditions was highlighted. A new mechanistic–empirical overlay thickness design method introduced in this study successfully identified structural deficiencies in the original pavement configurations.

Angiosperms at Gobindaganj Upazila of Gaibandha district, Bangladesh was studied from January to December 2018. An extensive floristic survey and angiosperms collection have been made throughout the study area. A total of 295 species belonging to 246 genera under 89 families were recorded. Plant habit analysis shows that herbs, shrubs, climbers and trees are represented by 47.45%, 15.93%, 12.20% and 24.40%, respectively. Distribution of angiosperm species in the families shows variation. Asteraceae is the most dominant family represented by 25 species, followed by Fabaceae (19 species), Euphorbiaceae (18 species), Cucurbitaceae (17 species), Acanthaceae (11 species), Solanaceae (11 species), Amaranthaceae (10 species) and Apocynaceae (10 species). 44 families are represented by a single species each while 37 families are represented by 2 to 8 species each. Status of occurrence has been recorded for proper conservation management and sustainable utilization of the taxa which show 218 (73.89%) to be common, 63 (21.35%) as rare, 10 (3.38%) as vulnerable, and 4 (1.35%) are found as endangered in the study area. For each species scientific name, voucher number, Bangla name, English name, habit, status of occurrence and flowering time were recorded.

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