Muller W.,ARRB Group Ltd. |
Muller W.,University of Queensland |
Scheuermann A.,University of Queensland
Journal of Geophysics and Engineering | Year: 2016
Measuring the electrical permittivity of civil engineering materials is important for a range of ground penetrating radar (GPR) and pavement moisture measurement applications. Compacted unbound granular (UBG) pavement materials present a number of preparation and measurement challenges using conventional characterisation techniques. As an alternative to these methods, a modified free-space (MFS) characterisation approach has previously been investigated. This paper describes recent work to optimise and validate the MFS technique. The research included finite difference time domain (FDTD) modelling to better understand the nature of wave propagation within material samples and the test apparatus. This research led to improvements in the test approach and optimisation of sample sizes. The influence of antenna spacing and sample thickness on the permittivity results was investigated by a series of experiments separating antennas and measuring samples of nylon and water. Permittivity measurements of samples of nylon and water approximately 100 mm and 170 mm thick were also compared, showing consistent results. These measurements also agreed well with surface probe measurements of the nylon sample and literature values for water. The results indicate permittivity estimates of acceptable accuracy can be obtained using the proposed approach, apparatus and sample sizes. © 2016 Sinopec Geophysical Research Institute.
Petho L.,ARRB Group Ltd. |
Toth C.,Budapest University of Technology and Economics
RILEM Bookseries | Year: 2012
Hot mix asphalt (HMA) performance in terms of fatigue resistance is a well-developed area of pavement design worldwide. Different equipment is available to predict the fatigue performance due to the well supported technical background.Sophisticated pavement design methods utilises the asphalt performance to predict pavement performance and the relative performance comparison between different mix types is also feasible.The research work presented in this paperprovidesan analytical approach to validate laboratory fatigue tests and in-service pavement performance. Large diameter cores (320 mm) were taken from heavily trafficked heavy duty pavement structures and subsequently 2 point bending tests were performed on the cut specimens. The pavement response to loading derived from the FWD measurement was compared to the performance obtained from the laboratory fatigue tests andthe remaining life of the pavement structure was assessed. © RILEM 2012.
Shayan A.,ARRB Group Ltd.
Proceedings of Institution of Civil Engineers: Construction Materials | Year: 2016
The effects of alkali-aggregate reaction (AAR) on concrete and structures start at the microstructural level, that is, at molecular and microscopic levels, such as the formation of reaction products in concrete and associated microcracking, which ultimately leads to macro-level effects such as visual cracking, differential movements, displacement and so on. The consequences of these effects are also wide ranging, and depend on the severity of the reaction, the configuration and functions of the affected element and the exposure conditions. The effects of AAR on concrete can range from minor cracking in non-load-bearing elements in benign environments, which may not have any significant consequence, to severe cracking in sensitive structural elements, particularly those exposed to aggressive environments, which could have serious detrimental effects on the mechanical and durability properties of concrete. This paper provides an overview of the changes that occur in the mechanical and durability properties of AAR-affected concrete elements. © 2016, Thomas Telford Services Ltd. All right reserved.
Saberi M.,Monash University |
Aghabayk K.,Monash University |
Sobhani A.,ARRB Group Ltd.
Physica A: Statistical Mechanics and its Applications | Year: 2015
Individual pedestrian velocities vary over time and space depending on the crowd size, location of individuals' within the crowd, and formation of self-organized lanes. We use empirical data to explore the spatial fluctuations of pedestrian velocities in bidirectional streams. We find that, unlike ordinary fluids, the velocity profile in bidirectional pedestrian streams does not necessarily follow a hyperbolic form. Rather, the shape of the velocity profile is highly dependent on the formation of self-organized lanes. We also show that the spatial fluctuations of pedestrian velocities along and transverse to the flow direction are widely distributed and can be modeled by a sum of Gaussian distributions. Results suggest that the effect of self-organization phenomenon is strong enough that for the same crowd size, the velocity distribution does not significantly change when pedestrians are highly mixed compared to when separate lanes are formed. © 2015 Elsevier B.V. All rights reserved.
Martin T.,ARRB Group Ltd.
Geotechnical Special Publication | Year: 2010
Some 85 of Australia's sealed road network is comprised of unbound granular pavements with a wearing surface treatment of stone aggregate embedded in a thin bituminous binder seal. Experimental pavement deterioration data gathered by means of accelerated load testing (ALT) on various forms of binder seal and stone aggregate over separate test pavements was used to estimate relative performance factors for cumulative rutting and roughness deterioration under these surface treatments. The ALT experiments were under controlled environmental conditions that were either continuously wet or continuously dry to allow modification of these relative performance factors for other environmental conditions. These relative performance factors have been applied to the observed deterioration of given surface treatments to develop road network deterioration (RD) models that allow prediction of the influence of various surface treatments on pavement deterioration. This paper demonstrates that when the relative performance factors are applied to the observed pavement deterioration under a given surface treatment to predict pavement deterioration under other forms of surface treatment, selection of a surface treatment option with the lowest pavement life-cycle cost is possible for a given traffic load and environmental condition. © 2010 ASCE.