Greg White - Academia.edu (original) (raw)
Papers by Greg White
International Journal of Pavement Research and Technology, 2021
Airfield and Highway Pavements 2021
Road Materials and Pavement Design
Construction and Building Materials, 2021
Abstract The compressive dynamic modulus (E*) and the flexural modulus (MF) of an asphalt mixture... more Abstract The compressive dynamic modulus (E*) and the flexural modulus (MF) of an asphalt mixture are two of the main criteria in structural design and evaluation of flexible pavements. The correlation between these properties and the characterisation of their trends indicates a dynamic response of the asphalt concrete mixtures. In this study, a non-dimensional compressive dynamic modulus index (φE*) and a non-dimensional flexural modulus index (φMF) are proposed as ways to characterise the trends of changes of the dynamic modulus at different temperatures and frequencies. Analysis of Variance (ANOVA) and Ridge Regression were used in analysis of different variables of experiments and statistical modelling, respectively. ANOVA results showed that the proposed parameters are function of the temperature, frequency, and the interactions. Also, the analysis of trends showed that the values of φMF converge at 3% as temperature increases, while only a decreasing trend was observed for φE*. Furthermore, the correlation between φMF and φE* depends on the type of binder. The effect of binder type can be seen in the master curves. Furthermore, the analysis showed that the values of MF are at least 75% of E*, so this can be used as proximity factor to convert MF into E* for use in mechanistic pavement design. In addition, a statistical predictive model was proposed as function of MF, temperature and frequency. The outputs showed that MF and temperature at the frequency domain have significant effects on E* with a high correlation. In conclusion, the proposed parameters and the model can be used as a basis for development of a universal predictive model of dynamic modulus through trends of changes and material properties.
Solving Pavement and Construction Materials Problems with Innovative and Cutting-edge Technologies, 2018
Traditionally, airport asphalt resurfacing works were delivered using a construct-only contract, ... more Traditionally, airport asphalt resurfacing works were delivered using a construct-only contract, requiring compliance with a design provided by the client, usually prepared by a design consultant. However, a number of generally compliant airport asphalt surfaces have failed to performed as required. Consequently, there is a desire to make asphalt contractors more responsible for the performance of airport asphalt surface that they have constructed. This paper describes the recent use of design and construct contracts for the delivery of airport asphalt resurfacing works in Australia. It is recommended that suitably sized and scoped airport asphalt resurfacing project consider a design and construct approach in the future. However, a robust preliminary design, nominated quantities for tendering and appropriate risk apportionment are all critical to project success.
Lecture Notes in Civil Engineering, 2022
Lecture Notes in Civil Engineering, 2022
Airfield and Highway Pavements 2021, 2021
Sustainable Civil Infrastructures, 2020
Sustainable Civil Infrastructures, 2018
Foamed bitumen base is one method for producing a bitumen stabilised granular material for paveme... more Foamed bitumen base is one method for producing a bitumen stabilised granular material for pavement construction. Foamed bitumen relies on the rapid expansion (foaming) of hot bitumen when introduced to cold water, temporarily reducing the viscosity of the bitumen, allowing mixing, placement and compaction. The resulting material is fast to construct, stiffer than crushed rock, moisture resistant and almost immediately able to support traffic, making it valuable for expedient pavement expansion and strengthening works. Airports with single runways often require expedient pavement construction methods and this paper presents foamed bitumen base through a case study on the runway strengthening at Whitsunday Coast Airport in Australia. Foamed bitumen base was produced ex-situ, initially using new crushed rock, prior to transitioning to the existing pavement materials. Challenges included the inability to recover existing pavement material in a representatively pulverised condition during the mixture design phase and the high sensitivity of the foamed bitumen base to production moisture content. Isolated underlying unsuitable materials were also encountered and this impacted the overall productivity and program. However, the relative density and resilient modulus of all samples exceeded the relevant requirements and foamed bitumen base is recommended to other airports requiring expedient pavement upgrade solutions.
Airfield and Highway Pavements 2021, 2021
Road & Transport Research, 2015
Bitumen supplies into Australia have become more diverse as importation of bitumen has become com... more Bitumen supplies into Australia have become more diverse as importation of bitumen has become common and Australian refineries have been closed or reduced in their capacity. The products on which empirical links between bitumen properties and field performance were established are likely to have changed over the years. This has undermined the effectiveness of the empirical bitumen specifications used in Australia. Similar experiences in New Zealand and South Africa prompted the introduction of performance-based testing. In the USA, the multiple stress creep recovery (MSCR) test was developed as a high-temperature performance grading criterion. The MSCR test is performed using a dynamic shear rheometer. A number of these devices are already available in Australia. The test is simple and takes about 15 minutes to complete. The MSCR test was adopted by the USA for high temperature performance grading of binders because of its advantages over the traditional G* /sin delta. The MSCR was ...
Australian Journal of Civil Engineering, 2021
Foamed bitumen stabilisation is a unique pavement treatment option for improving new granular mat... more Foamed bitumen stabilisation is a unique pavement treatment option for improving new granular materials or rehabilitating existing granular layers that have exceeded their serviceable life. As a ty...
The empirical basis for aircraft pavement thickness determination is the full scale trafficking t... more The empirical basis for aircraft pavement thickness determination is the full scale trafficking tests performed by the US Corps of Engineers between the 1940s and 1970s. This culminated in the publishing of the S77-1 design method, which relates subgrade deflection to the number of allowable repetitions of that deflection. Pavement life was found to depend not only upon the magnitude of deflection, but also upon the aircraft wheel configuration that produced that deflection. Consequently, different pavement thickness adjustment factors, called Alpha Factors, were required for each different wheel configuration. APSDS uses strain as its indicator of pavement damage. The APSDS relationships between strain and pavement life were not obtained by direct calibration against the Corps’ full-scale trafficking tests, but by calibrating against S77-1. The initial APSDS calibration considered only dual and dual-tandem aircraft at maximum weight, and two coverage levels of 10,000 and 100,000. T...
Sustainable Civil Infrastructures, 2018
In recent years, software has been developed to calculate aircraft pavement strength ratings from... more In recent years, software has been developed to calculate aircraft pavement strength ratings from modulus values that are back-calculated from deflections measured by a falling weight deflectometer. Deflection data from a uniform section of consistent runway pavement was analysed for variability to determine the effect of deflection variability on back-calculated modulus and the resulting pavement strength rating. The drop force of the falling weight had a significant influence on the calculated pavement strength, with 50 kN drop force rating the pavement approximately 35% lower than the 100 kN drop force. The number of layers in the nominated pavement structure also had a significant influence on the back-calculated modulus values, but not the resulting pavement strength rating. Compared to traditional design-based evaluation using intrusively measured layer thicknesses and laboratory material characterisation, the falling weight deflection back-calculation underestimated the pavem...
Plastic drink bottles, single-use plastic bags and other waste plastics have a significant impact... more Plastic drink bottles, single-use plastic bags and other waste plastics have a significant impact on the environment. Consequently, there is global interest in recycling and reuse of waste plastics. Significant progress has been made towards the incorporation of waste plastics into building and construction materials, although this has focussed mainly on cement and concrete applications. This paper assesses the use of three commercially available recycled plastic products for bituminous binder extension and modification in asphalt mixtures. Using a drymixing process, shredded and pelletised recycled waste plastics replace 6% of the binder volume. Comparative laboratory testing of two typical UK asphalt mixtures indicated that asphalt containing the recycled waste plastic products showed improved deformation resistance and fracture resistance compared to conventional 40/60 penetration grade binder. The viability of imported recycled plastic waste use in Australian asphalt mixtures wa...
Airfield and Highway Pavements 2017, 2017
Proceedings of the 12th International Conference on Concrete Pavements, 2021
FAARFIELD is a common mechanistic-empirical software that uses a combination of layered elastic a... more FAARFIELD is a common mechanistic-empirical software that uses a combination of layered elastic and finite element methods for the determination of rigid aircraft pavement thickness. The primary input parameters are the aircraft type, mass and departures, concrete flexural strength, sub-base material and thickness, as well as subgrade support characteristic. A parametric sensitivity analysis, including three common commercial aircraft and four subgrade conditions, determined that concrete thickness was most sensitive to concrete strength and aircraft mass. The concrete thickness was least sensitive to the sub-base material and thickness and was moderately sensitive to the subgrade condition and aircraft departures. These relative sensitivities were consistent when the results were analysed based on average percentage change in concrete thickness, the average slope of lines of best fit for normalised parameter values and the coefficients of a numeric linear regression for concrete th...
The Australian Department of Defence manages, maintains and operates twenty-four airfields around... more The Australian Department of Defence manages, maintains and operates twenty-four airfields around Australia. These airfields range in their size, infrastructure provisions, operational capability and environment. Over the last ten years, the management of maintenance at these airfields has uncovered unique problems, allowed trials of various maintenance approaches to be conducted and presented many opportunities to learn valuable lessons for the future. Surface enrichment of asphalt using both tar-based and bitumen-based materials has been performed on many pavements. This has proven to be an effective means of increasing the period between asphalt overlays. Such treatments require careful attention to the application rates and selection of the enrichment product. The interface between concrete and asphalt surfaced pavements presents a design challenge. If not detailed appropriately, differential thermal expansion and contraction can lead to shoving and cracking of asphalt as well a...
International Journal of Pavement Research and Technology, 2021
Airfield and Highway Pavements 2021
Road Materials and Pavement Design
Construction and Building Materials, 2021
Abstract The compressive dynamic modulus (E*) and the flexural modulus (MF) of an asphalt mixture... more Abstract The compressive dynamic modulus (E*) and the flexural modulus (MF) of an asphalt mixture are two of the main criteria in structural design and evaluation of flexible pavements. The correlation between these properties and the characterisation of their trends indicates a dynamic response of the asphalt concrete mixtures. In this study, a non-dimensional compressive dynamic modulus index (φE*) and a non-dimensional flexural modulus index (φMF) are proposed as ways to characterise the trends of changes of the dynamic modulus at different temperatures and frequencies. Analysis of Variance (ANOVA) and Ridge Regression were used in analysis of different variables of experiments and statistical modelling, respectively. ANOVA results showed that the proposed parameters are function of the temperature, frequency, and the interactions. Also, the analysis of trends showed that the values of φMF converge at 3% as temperature increases, while only a decreasing trend was observed for φE*. Furthermore, the correlation between φMF and φE* depends on the type of binder. The effect of binder type can be seen in the master curves. Furthermore, the analysis showed that the values of MF are at least 75% of E*, so this can be used as proximity factor to convert MF into E* for use in mechanistic pavement design. In addition, a statistical predictive model was proposed as function of MF, temperature and frequency. The outputs showed that MF and temperature at the frequency domain have significant effects on E* with a high correlation. In conclusion, the proposed parameters and the model can be used as a basis for development of a universal predictive model of dynamic modulus through trends of changes and material properties.
Solving Pavement and Construction Materials Problems with Innovative and Cutting-edge Technologies, 2018
Traditionally, airport asphalt resurfacing works were delivered using a construct-only contract, ... more Traditionally, airport asphalt resurfacing works were delivered using a construct-only contract, requiring compliance with a design provided by the client, usually prepared by a design consultant. However, a number of generally compliant airport asphalt surfaces have failed to performed as required. Consequently, there is a desire to make asphalt contractors more responsible for the performance of airport asphalt surface that they have constructed. This paper describes the recent use of design and construct contracts for the delivery of airport asphalt resurfacing works in Australia. It is recommended that suitably sized and scoped airport asphalt resurfacing project consider a design and construct approach in the future. However, a robust preliminary design, nominated quantities for tendering and appropriate risk apportionment are all critical to project success.
Lecture Notes in Civil Engineering, 2022
Lecture Notes in Civil Engineering, 2022
Airfield and Highway Pavements 2021, 2021
Sustainable Civil Infrastructures, 2020
Sustainable Civil Infrastructures, 2018
Foamed bitumen base is one method for producing a bitumen stabilised granular material for paveme... more Foamed bitumen base is one method for producing a bitumen stabilised granular material for pavement construction. Foamed bitumen relies on the rapid expansion (foaming) of hot bitumen when introduced to cold water, temporarily reducing the viscosity of the bitumen, allowing mixing, placement and compaction. The resulting material is fast to construct, stiffer than crushed rock, moisture resistant and almost immediately able to support traffic, making it valuable for expedient pavement expansion and strengthening works. Airports with single runways often require expedient pavement construction methods and this paper presents foamed bitumen base through a case study on the runway strengthening at Whitsunday Coast Airport in Australia. Foamed bitumen base was produced ex-situ, initially using new crushed rock, prior to transitioning to the existing pavement materials. Challenges included the inability to recover existing pavement material in a representatively pulverised condition during the mixture design phase and the high sensitivity of the foamed bitumen base to production moisture content. Isolated underlying unsuitable materials were also encountered and this impacted the overall productivity and program. However, the relative density and resilient modulus of all samples exceeded the relevant requirements and foamed bitumen base is recommended to other airports requiring expedient pavement upgrade solutions.
Airfield and Highway Pavements 2021, 2021
Road & Transport Research, 2015
Bitumen supplies into Australia have become more diverse as importation of bitumen has become com... more Bitumen supplies into Australia have become more diverse as importation of bitumen has become common and Australian refineries have been closed or reduced in their capacity. The products on which empirical links between bitumen properties and field performance were established are likely to have changed over the years. This has undermined the effectiveness of the empirical bitumen specifications used in Australia. Similar experiences in New Zealand and South Africa prompted the introduction of performance-based testing. In the USA, the multiple stress creep recovery (MSCR) test was developed as a high-temperature performance grading criterion. The MSCR test is performed using a dynamic shear rheometer. A number of these devices are already available in Australia. The test is simple and takes about 15 minutes to complete. The MSCR test was adopted by the USA for high temperature performance grading of binders because of its advantages over the traditional G* /sin delta. The MSCR was ...
Australian Journal of Civil Engineering, 2021
Foamed bitumen stabilisation is a unique pavement treatment option for improving new granular mat... more Foamed bitumen stabilisation is a unique pavement treatment option for improving new granular materials or rehabilitating existing granular layers that have exceeded their serviceable life. As a ty...
The empirical basis for aircraft pavement thickness determination is the full scale trafficking t... more The empirical basis for aircraft pavement thickness determination is the full scale trafficking tests performed by the US Corps of Engineers between the 1940s and 1970s. This culminated in the publishing of the S77-1 design method, which relates subgrade deflection to the number of allowable repetitions of that deflection. Pavement life was found to depend not only upon the magnitude of deflection, but also upon the aircraft wheel configuration that produced that deflection. Consequently, different pavement thickness adjustment factors, called Alpha Factors, were required for each different wheel configuration. APSDS uses strain as its indicator of pavement damage. The APSDS relationships between strain and pavement life were not obtained by direct calibration against the Corps’ full-scale trafficking tests, but by calibrating against S77-1. The initial APSDS calibration considered only dual and dual-tandem aircraft at maximum weight, and two coverage levels of 10,000 and 100,000. T...
Sustainable Civil Infrastructures, 2018
In recent years, software has been developed to calculate aircraft pavement strength ratings from... more In recent years, software has been developed to calculate aircraft pavement strength ratings from modulus values that are back-calculated from deflections measured by a falling weight deflectometer. Deflection data from a uniform section of consistent runway pavement was analysed for variability to determine the effect of deflection variability on back-calculated modulus and the resulting pavement strength rating. The drop force of the falling weight had a significant influence on the calculated pavement strength, with 50 kN drop force rating the pavement approximately 35% lower than the 100 kN drop force. The number of layers in the nominated pavement structure also had a significant influence on the back-calculated modulus values, but not the resulting pavement strength rating. Compared to traditional design-based evaluation using intrusively measured layer thicknesses and laboratory material characterisation, the falling weight deflection back-calculation underestimated the pavem...
Plastic drink bottles, single-use plastic bags and other waste plastics have a significant impact... more Plastic drink bottles, single-use plastic bags and other waste plastics have a significant impact on the environment. Consequently, there is global interest in recycling and reuse of waste plastics. Significant progress has been made towards the incorporation of waste plastics into building and construction materials, although this has focussed mainly on cement and concrete applications. This paper assesses the use of three commercially available recycled plastic products for bituminous binder extension and modification in asphalt mixtures. Using a drymixing process, shredded and pelletised recycled waste plastics replace 6% of the binder volume. Comparative laboratory testing of two typical UK asphalt mixtures indicated that asphalt containing the recycled waste plastic products showed improved deformation resistance and fracture resistance compared to conventional 40/60 penetration grade binder. The viability of imported recycled plastic waste use in Australian asphalt mixtures wa...
Airfield and Highway Pavements 2017, 2017
Proceedings of the 12th International Conference on Concrete Pavements, 2021
FAARFIELD is a common mechanistic-empirical software that uses a combination of layered elastic a... more FAARFIELD is a common mechanistic-empirical software that uses a combination of layered elastic and finite element methods for the determination of rigid aircraft pavement thickness. The primary input parameters are the aircraft type, mass and departures, concrete flexural strength, sub-base material and thickness, as well as subgrade support characteristic. A parametric sensitivity analysis, including three common commercial aircraft and four subgrade conditions, determined that concrete thickness was most sensitive to concrete strength and aircraft mass. The concrete thickness was least sensitive to the sub-base material and thickness and was moderately sensitive to the subgrade condition and aircraft departures. These relative sensitivities were consistent when the results were analysed based on average percentage change in concrete thickness, the average slope of lines of best fit for normalised parameter values and the coefficients of a numeric linear regression for concrete th...
The Australian Department of Defence manages, maintains and operates twenty-four airfields around... more The Australian Department of Defence manages, maintains and operates twenty-four airfields around Australia. These airfields range in their size, infrastructure provisions, operational capability and environment. Over the last ten years, the management of maintenance at these airfields has uncovered unique problems, allowed trials of various maintenance approaches to be conducted and presented many opportunities to learn valuable lessons for the future. Surface enrichment of asphalt using both tar-based and bitumen-based materials has been performed on many pavements. This has proven to be an effective means of increasing the period between asphalt overlays. Such treatments require careful attention to the application rates and selection of the enrichment product. The interface between concrete and asphalt surfaced pavements presents a design challenge. If not detailed appropriately, differential thermal expansion and contraction can lead to shoving and cracking of asphalt as well a...