Automation, Worker Welfare, and Productivity: Field Evidence

2019 ◽  
Author(s):  
Ivan P. L. Png
Keyword(s):  
Field Evidence

Fracture-Tolerant and Shear-Resistant Interlayers for Mitigation of Reflective Cracking

2019 ◽  
Vol 2673 (10) ◽  
pp. 35-46
Author(s):  
Cristian Cocconcelli ◽  
Bongsuk Park ◽  
Jian Zou ◽  
George Lopp ◽  
Reynaldo Roque
Keyword(s):  
Asphalt Pavement ◽  
Aggregate Size ◽  
Cost Effective ◽  
Design Guidelines ◽  
Reflective Cracking ◽  
Rubber Membrane ◽  
Near Surface ◽  
Field Evidence ◽  
Cracking Performance ◽  
Interface Cracking

Reflective cracking is frequently reported as the most common distress affecting resurfaced pavements. An asphalt rubber membrane interlayer (ARMI) approach has been traditionally used in Florida to mitigate reflective cracking. However, recent field evidence has raised doubts about the effectiveness of the ARMI when placed near the surface, indicating questionable benefits to reflective cracking and increased instability rutting potential. The main purpose of this research was to develop guidelines for an effective alternative to the ARMI for mitigation of near-surface reflective cracking in overlays on asphalt pavement. Fourteen interlayer mixtures, covering three aggregate types widely used in Florida, and two nominal maximum aggregate sizes (NMAS) were designed according to key characteristics identified for mitigation of reflective cracking, that is, sufficient gradation coarseness and high asphalt content. The dominant aggregate size range—interstitial component (DASR-IC) model was used for the design of all mixture gradations. A composite specimen interface cracking (CSIC) test was employed to evaluate reflective cracking performance of interlayer systems. In addition, asphalt pavement analyzer (APA) tests were performed to determine whether the interlayer mixtures had sufficient rutting resistance. The results indicated that interlayer mixtures designed with lower compaction effort, reduced design air voids, and coarser gradation led to more cost-effective fracture-tolerant and shear-resistant (FTSR) interlayers. Therefore, preliminary design guidelines including minimum effective film thickness and maximum DASR porosity requirements were proposed for 9.5-mm NMAS (35 µm and 50%) and 4.75-mm NMAS FTSR mixtures (20 µm and 60%) to mitigate near-surface reflective cracking.

scholarly journals Unmanned Aerial Systems-Aided Post-Flood Peak Discharge Estimation in Ephemeral Streams

2020 ◽  
Vol 12 (24) ◽  
pp. 4183
Author(s):  
Emmanouil Andreadakis ◽  
Michalis Diakakis ◽  
Emmanuel Vassilakis ◽  
Georgios Deligiannakis ◽  
Antonis Antoniadis ◽  
...  
Keyword(s):  
Flash Flood ◽  
Traditional Approach ◽  
Peak Discharge ◽  
Unmanned Aerial Systems ◽  
Monitoring Networks ◽  
Response Dynamics ◽  
Hydrologic Modelling ◽  
Flood Peak ◽  
Field Evidence ◽  
Aerial Systems

The spatial and temporal scale of flash flood occurrence provides limited opportunities for observations and measurements using conventional monitoring networks, turning the focus to event-based, post-disaster studies. Post-flood surveys exploit field evidence to make indirect discharge estimations, aiming to improve our understanding of hydrological response dynamics under extreme meteorological forcing. However, discharge estimations are associated with demanding fieldwork aiming to record in small timeframes delicate data and data prone-to-be-lost and achieve the desired accuracy in measurements to minimize various uncertainties of the process. In this work, we explore the potential of unmanned aerial systems (UAS) technology, in combination with the Structure for Motion (SfM) and optical granulometry techniques in peak discharge estimations. We compare the results of the UAS-aided discharge estimations to estimates derived from differential Global Navigation Satellite System (d-GNSS) surveys and hydrologic modelling. The application in the catchment of the Soures torrent in Greece, after a catastrophic flood, shows that the UAS-aided method determined peak discharge with accuracy, providing very similar values compared to the ones estimated by the established traditional approach. The technique proved to be particularly effective, providing flexibility in terms of resources and timing, although there are certain limitations to its applicability, related mostly to the optical granulometry as well as the condition of the channel. The application highlighted important advantages and certain weaknesses of these emerging tools in indirect discharge estimations, which we discuss in detail.

Mo Contamination in Rivers near the Erdenet Mining Area, Mongolia: Field Evidence of High Mobility of Mo at pH >8

2021 ◽  
Author(s):  
Solongo Tsetsgee ◽  
Akihiro Okuyama ◽  
Altansukh Ochir ◽  
Ariuntungalag Yunden ◽  
Enkhjin Odgerel ◽  
...  
Keyword(s):  
High Mobility ◽  
Mining Area ◽  
Field Evidence
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