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Stone mastic asphalt as an ungrooved runway surface: Case study on Emerald airport
Published in Inge Hoff, Helge Mork, Rabbira Saba, Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Volume 1, 2021
In addition to the normal construction verification processes, the construction trial allowed a relaxation of the SMA thickness to be tested. The SMA trial was nominally 40-65 mm thick. There was no difference in the surface texture, visual appearance, air voids, level control or joint condition noticed throughout the variable thickness SMA trial section. Consequently, the SMA single layer thickness limits were relaxed from 45-55 mm to 45-65 mm, significantly reducing the area of correction layer required and the volume of existing surface profiling required to accommodate the minimum correction later thickness. The trial also allowed the nuclear density gauge to be calibrated to both the DGA and SMA mixtures, which is critical when non-destructive (gauge-based) density testing is adopted for construction acceptance (White & Alrashidi 2021).
Variability of Light Weight Deflectometer during laboratory and field applications for subgrade soils under variable moisture conditions
Published in Andreas Loizos, Imad L. Al-Qadi, A. (Tom) Scarpas, Bearing Capacity of Roads, Railways and Airfields, 2017
Mehran Mazari, Gerardo Garcia, Imad Abdallah, Jose Garibay, Soheil Nazarian
Performance of pavement structures mostly depend on the structural behavior of unbound granular layers and most of the pavement deteriorations could be traced to the insufficient strength of these materials. The current state of practice for Quality Control and Quality Assurance (QC/QA) during the construction process is the estimation of density and sometimes the moisture content using a Nuclear Density Gauge (NDG). On the other hand, the main parameter used for the mechanistic-empirical design of flexible pavements is modulus. Consequently, there is a missing link between the design and QC/QA processes which reflects the need for a modulus-based construction quality control approach.
Nuclear density gauge compaction testing alternatives: synthesis and critical analysis
Published in Journal of Structural Integrity and Maintenance, 2019
While the speed and accuracy of the nuclear density gauge (NDG) are unquestioned, its use of hazardous radioactive material imposes burdensome administrative requirements for the device’s use, storage and transport, not to mention the costs to continually train, certify and recertify the technicians that take field tests. The use of the NDG to find both the density and moisture of a compacted course is ubiquitous. The NDG’s major advantage is its ability to rapidly measure density and moisture content, typically taking between 1 and 4 minutes of testing time (ASTM, 2010). While the NDG is reliable and efficient, it also gives rise to a considerable expenditure of time and expense to meet the statutory requirements of the U.S. Nuclear Regulatory Commission and state emergency management agencies for technician safety training, radiation and certification classes, licenses and storage facilities (2). This time and expense are borne by both the agencies and their construction contractors and materials testing consultants.