rut

Maintenance and rehabilitation of the road are very serious actions. Therefore, road conditions should be inspected accurately before taking these actions. Manual and visual inspection in the field is the traditionally used method to monitor road conditions. However, it is time-consuming, labor-intense and costly. In addition, the traditional inspection method is unsafe directly for the inspectors and indirectly for primary users of the road, such as pedestrians and drivers. In this study, the unmanned aerial vehicle (UAV) was used to inspect the road condition. UAV technology is becoming a valuable tool for collecting data efficiently and accurately. The proposed method involved three steps. First, several images were acquired from a UAV flight. Then, these images were used to generate a three-dimensional (3D) point cloud, digital surface model and orthomosaic. Finally, road distresses were detected and measured from two-dimensional (2D) and 3D data. The measurements obtained from the proposed methodology were compared against the measurements obtained from the traditional inspection method. It was found that both measurements produced similar results. In conclusion, the use of the UAV measurement technique was found to be suitable for detecting road distress. Given the advantages of the proposed methodology, it can also be inferred that UAVs can be used instead of the traditional inspection method.

The use of warm mix asphalt (WMA) technology has increased dramatically in recent years to protect the environment and reduce energy consumption. Despite numerous advantages, WMAs are less commonly used as a result of their lower performance in comparison to HMAs. One of the main reasons for the low performance of WMAs is their high moisture sensitivity. In recent decades, bitumen modifiers have been used to improve the performance of asphalt mixtures. One of the additives that has recently been used to modify the characteristics of bitumen, is bentonite. The grade of asphalt cement used in this study is PG 64 -22 and the Bitumen is modified with 1, 3, 5 and 7% nano bentonite. Also, 0.3% fatty Arbocel has been used for the preparation of WMA. Indirect tensile strength (ITS) test and Nicholson stripping test are used to determine moisture sensitivity and dynamic creep test and LCPC are also used to evaluate the rutting potential. The results indicate that, increasing the percentage o...

The social organization of giraffes ( Giraffa camelopardalis ) imposes a high-cost reproductive strategy on bulls, which adopt a ‘roving male’ tactic. Our observations on wild giraffes confirm that bulls indeed have unsynchronized rut-like periods, not unlike another tropical megaherbivore, the elephant, but on a much shorter timescale. We found profound changes in male sexual and social activities at the scale of about two weeks. This so far undescribed rutting behaviour is closely correlated with changes in androgen concentrations and appears to be driven by them. The short time scale of the changes in sexual and social activity may explain why dominance and reproductive status in male giraffe in the field seem to be unstable.

The new FHWA Mechanistic–Empirical Pavement Design Guide (M-E PDG) does away with the AASHO-derived concept of the equivalent single-axle load and calculates damage caused by various axle configurations directly. Because multiple axles represent about half the axle configurations that the pavement will experience, there is a need to evaluate the M-E PDG procedure for predicting rutting due to multiple-axle configurations. Axle factors (AFs) based on rutting were calculated for different axle configurations by using three procedures: the M-E PDG, accounting for the effect of each individual axle within a group, and integrating the entire strain pulse. The AFs from these procedures were compared with laboratory-derived values for asphalt concrete. Also, layer rutting contributions were predicted for six in-service SPS-1 experiment sections from the Long-Term Pavement Performance Program with the M-E PDG software and were compared with the analysis of their transverse surface profiles....

Acrylonitrile styrene acrylate (ASA) plastic and stamp sand are both waste materials that impose a significant burden on the environment. This study investigates the potential of using stamp sand and ASA plastic composite as pavement or road surfacing mixture. It should be noted that this new material does not use asphalt materials. A series of lab tests usually used for asphalt pavement materials were employed for the stamp sand and ASA plastic composite material. The dynamic modulus test was performed to reflect the deformation under different load and frequency levels. The high-temperature properties were assessed by the Hamburg wheel tracking device (HWTD), and the low-temperature performance was assessed by the disc-shaped compact tension (DCT) test. The moisture susceptibility was determined by the dry/wet strength ratio. The coefficient of permeability was estimated by the water permeability test, and the mass loss of aggregate was estimated by the Cantabro loss test. The dynamic modulus results showed that the ASA mixtures have improved high-temperature deformation resistance as compared to the asphalt mixtures. The ASA mixture with 40% sand showed higher stiffness than the ASA mixture with 30% sand. The ASA mixtures have excellent rutting resistance and moisture damage resistance. The fracture energy of the asphalt mixture is 42-77% higher than the ASA mixture. The tensile strength ratio of the ASA and asphalt mixture are all larger than 0.8 and therefore satisfy the Superpave specification. The average coefficient of permeability of the ASA mixture is 6-10 times higher than the asphalt mixture in the same air void level. The average aggregate loss percent of the ASA mixtures is 9.2-10.8 times higher than asphalt mixtures. In summary, the implementation of stamp sand and ASA plastic mixtures may be a successful solution