DEVELOPMENT OF HIGH MODULUS ASPHALT CONCRETE MIX DESIGN TECHNOLOGY FOR USE ON ONTARIO’S HIGHWAYS

Asphalt pavement is subjected to external loads including mechanical loading induced by traffic and thermal loading induced by thermal variations. The last decades have witnessed a significant rise in number of heavy vehicles especially commercial trucks with higher axle loads on rural and arterial roads in Ontario. Consequently, by increasing the number and amplitude of traffic loading and severe environmental condition, servile life of asphalt pavements has been adversely affected. In many cases, premature distresses were occurred before expected service life of asphalt pavements reaches to its end. On the other hand, new pavement materials, design procedures and construction technologies have been developed worldwide. One of these technologies is “Enrobé à Module Élevé- (EME)” or “High-Modulus Asphalt Mix”. EME is a type of asphalt concrete that represents high modulus/stiffness, high durability, superior rutting performance and good fatigue resistance. This type of mix was developed in France in the 1980’s. EME is a very good option to be used in lower and upper binder courses in the pavement structure which are subject to the highest levels of tensile and compressive stresses. EME offers several advantages over conventional binder course materials including reducing the thickness of the pavement structure with improved service life and reduction in raw materials consumption. Despite the excellent performance at higher and intermediate temperatures, traditional EME mixes would be very susceptible to low-temperature cracking which is associated to using very hard grade asphalt binder. In addition to the cold climate condition, some other aspects such as traffic volume, vehicle attributes, properties of raw materials, construction methods, and testing standards are specific to Ontario. Based on the aforementioned reasons, adopting EME technology will be beneficial to Ontario’s highways. However, development of a suitable EME mix design procedure in Ontario cannot be a duplicate copy of the French method, or any other methods used in other countries or jurisdictions. This study, funded by the Highway Infrastructure Innovation Funding Program (HIIFP-2015), aims to introduce a new approach to EME mix design that contributes to good performance at high, medium and low temperatures. This could be achieved by using premium aggregate particles with dense structure (high packing density), along with utilizing high quality asphalt binder with precise content in the mix. A performance-based mix design approach is developed for EME mix design in Ontario which is a modified version of Superpave mix design procedure. Compressible Packing Model (CPM) was used for the first time to optimize the packing density of aggregate particles for two categories of mixes (12.5 mm and 19 mm Nominal Maximum Aggregate Size (NMAS)). Three types of modified asphalt binders were also considered: PG 88-28, PG 82-28 and PG 58-28 + modifiers (Elastomer additives). In addition to measuring compaction ability (compactibility) of the developed mixes, several thermo-mechanical testing methods were designated to be used in this study to evaluate the performance of asphalt mixes at different levels. Results of this study showed that the CPM-obtained gradation limits were within the grading control points of EME mixes recommended by French specification. The asphalt mixes had higher compactibility than the conventional mix, and, EME 19 was more compactible than EME 12.5 although it had less binder content than EME 12.5. Complex modulus test results illustrated that the mixes had high modulus values, and that the values of EME 19 were generally higher than those of EME 12.5. Hamburg wheel track rutting test results showed both mix types had superior rutting performance. Fatigue performance of developed mixes was assessed using four-point bending beam fatigue test at different strain levels to develop fatigue curves. The test results showed that the minimum strain level to meet 1,000,000 cycles of fatigue life (ε6) was more than 300 μm/m for all the mixes. Additionally, Thermal Stress Restrained Specimen Test (TSRST) results showed that the cracking temperatures of the developed mixes were less than -25˚C; and that EME 12.5 performed slightly better than EME 19. Binder microstructure and rheological properties were assessed using environmental scanning electron microscope (ESEM) and dynamic shear rheometer (DSR) equipment respectively. Two springs, two parabolic elements and one dashpot (2S2P1D) rheological model is used to model and compare the viscoelastic behavior of the binders as well as the mixes. ESEM test results showed that microstructure of PG 88-28 binder was the densest and connected with thicker fibril size. PG 58-28 + Elastomer additives had highly intertwined structural network with the thinnest fibril size among the binder types. 2S2P1D results showed it is a powerful tool for modeling highly polymer modified asphalt binders as well as EME mixes. According to developed master curves the mixes’ moduli have followed the same pattern as for the binders’ although phase angles’ patterns were different. Correlations were found between the binders’ microstructures and their rheological properties. Binders with denser structure and stronger bonds showed to have lower phase angles. Although binders with more intertwined structural network had higher modulus particularly at higher frequencies. The EME mix design approach was validated by using the second source of aggregate materials and PG 82-28 asphalt binder. The SGC compactibility test results showed that the mixes were more compactible than the conventional Superpave mix. According to the rutting test results, the mixes had almost not rut after 20,000 wheel passes on the submerged specimens at 50°C (rut-depth < 1 mm). In addition, the developed mixes with the second source of aggregates had relatively higher fatigue resistance where ε6 values were greater than 550 μm/m for both EME 12.5 and EME 19. TSRST results also depicted that the cracking temperatures of both mixes were below -30°C

The effect of near ultraviolet radiation on the morphology of nylon 66

Photodegradation of nylon 66 resulting from outdoor exposure and simulated weather conditions has been reported. Tensile strength losses and photochemical decomposition have been shown to occur on exposure to broad band irradiation. Physical properties of textile materials are intimately related to fiber structure. Therefore, any insights into phenomena which alter that structure, and consequently affect the expected performance of textile goods, would be useful . This study examined the morphology of nylon 66 fibers as affected by near ultraviolet (UV) irradiation in a dry oxygen atmosphere. Ninety percent emission from the irradiation source was at 3500 ± 500 A, a wavelength range found in sunlight at the earth's surface

Reducing Produced Water Disposal Via Effective Treatments Methods And Re-Use: Proposed Sustainable Application For Bakken, North Dakota

It is true that the advancements in both the hydraulic frack and directional drilling technologies led to less time and a bit easier ways to develop unconventional oil and gas assets worldwide. In the Bakken North Dakota, the result of these breakthroughs and advancements in technologies are that they drastically reduce the time it takes to drill and complete a well leading to more wells (347 in 2004 to 16,300 in 2020). In 2019, the United States became the largest global crude oil producer, and the unconventional Bakken Play in North Dakota is one of the major contributors to this feat. As more wells are being drilled, more waste water are being produced. Analysis also showed early increases in water cuts even in younger (less than 3 years) wells drilled around McKenzie and Williams Counties. The concern here is that the wastewater produced by these increased oilfield activities is highly saline (~170,000 to 350,000 ppm TDS), and the most commonly used water disposal method in the Bakken Formation is deep injection into disposal wells. Notwithstanding, there are growing environmental and operational concerns about the sustainability and impacts of this approach. However, if the wastewater is efficiently treated, it could be reused in hydraulic fracturing operations or to support coal mining and irrigation activities. This research uses various method to investigate the root cause of the high volume of wastewater production in the Bakken, North Dakota and how these flow back and produced water could be treated using various novel technologies like, the advanced and improved desalination, advanced electro-oxidation and dilution methods. Lastly, the research was able to provide robust and detailed results on how the Bakken treated produced water could be transformed to good use especially as base fluids for hydraulic frack fluid formulation

Physical activity, sex, and obesity: the effects on aging brains

During aging, vascular declines occur causing cerebral atrophy, and functional deteriorations. When this decline is faster than the expected age-related decline, a heightened risk of developing dementia can occur. Understanding what risk factors contribute most to cerebral health across the lifespan prior to the onset of vascular changes is of upmost importance. Potential mediators of the aging vascular system include non-modifiable outcomes such as sex, and modifiable factors like physical activity level (PA) and body mass index (BMI). This thesis includes one systematic review and three original studies investigating the effectiveness of PA to enhance cerebral health. In manuscript one we conducted a systematic review of cognitive or exercise interventions in healthy older adults that collected magnetic resonance imaging (MRI) scans. We identified that cognitive training was associated with white matter microstructure improvements, exercise training with macrostructural enhancements, and both demonstrated changes to the blood oxygen level dependent signal, indicating changes to hemodynamics, neuronal resources, or efficiency. However, the underlying mechanisms for enhanced cerebral health were unclear given the heterogeneity of interventions, measurements, and samples in terms of age and health status. In manuscript two, we investigated very healthy older adults with no underlying comorbidities comprehend the relationship between cardiovascular fitness and cerebral hemodynamics. We revealed paradoxical findings of greater cardiovascular fitness associated with decreased cerebrovascular reactivity, but preserved structure. In a normal aging sample, the relationship between sex, BMI, PA, and structural outcomes was examined. Females with greater BMI had enhanced structural outcomes, and regardless of BMI, higher PA was beneficial to cerebral health. In contrast, overweight males had the greatest volumetrics and PA did not have much influence on these relationships. The final manuscript incorporated a larger age range of individuals, showing an overall beneficial effect of PA on cerebral blood flow (CBF), but males and females demonstrated unique relationships with CBF, and the intensity of PA reported, which was further influenced by whether they were middle aged or older. Therefore, our studies contribute to our understanding of the beneficial effects of PA on brain health, and how these effects are influenced by sex, age, and obesity

Research and Technology 1996: Innovation in Time and Space

As the NASA Center responsible for assembly, checkout, servicing, launch, recovery, and operational support of Space Transportation System elements and payloads, the John F. Kennedy Space Center is placing increasing emphasis on its advanced technology development program. This program encompasses the efforts of the Engineering Development Directorate laboratories, most of the KSC operations contractors, academia, and selected commercial industries - all working in a team effort within their own areas of expertise. This edition of the Kennedy Space Center Research and Technology 1996 Annual Report covers efforts of all these contributors to the KSC advanced technology development program, as well as our technology transfer activities

Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields

Innovations in Road, Railway and Airfield Bearing Capacity – Volume 1 comprises the first part of contributions to the 11th International Conference on Bearing Capacity of Roads, Railways and Airfields (2022). In anticipation of the event, it unveils state-of-the-art information and research on the latest policies, traffic loading measurements, in-situ measurements and condition surveys, functional testing, deflection measurement evaluation, structural performance prediction for pavements and tracks, new construction and rehabilitation design systems, frost affected areas, drainage and environmental effects, reinforcement, traditional and recycled materials, full scale testing and on case histories of road, railways and airfields. This edited work is intended for a global audience of road, railway and airfield engineers, researchers and consultants, as well as building and maintenance companies looking to further upgrade their practices in the field

Recent Advances and Future Trends in Pavement Engineering

This Special Issue “Recent Advances and Future Trends in Pavement Engineering” was proposed and organized to present recent developments in the field of innovative pavement materials and engineering. The 12 articles and state-of-the-art reviews highlighted in this editorial are related to different aspects of pavement engineering, from recycled asphalt pavements to alkali-activated materials, from hot mix asphalt concrete to porous asphalt concrete, from interface bonding to modal analysis, and from destructive testing to non-destructive pavement monitoring by using fiber optics sensors. This Special Issue partly provides an overview of current innovative pavement engineering ideas that have the potential to be implemented in industry in the future, covering some recent developments

Characterisation of waxy gas-condensates by high temperature capillary gas chromatography and oxidative degradation

High molecular weight (HMW) hydrocarbons (defined herein as C35+ compounds) are difficult to characterise by conventional analytical methods. Very few studies have reported precise and reproducible quantification of such compounds in fossil fuels. Nonetheless, such components have important effects on the physical and biological fate of fossil fuels in the geosphere. For example, the phase behaviour of waxy gas condensates is significantly affected by the varying proportions of HMW compounds. Similarly HMW compounds are amongst the most resistant petroleum components to biodegradation. The current study reports the development of reproducible quantitative high temperature capillary gas chromatography (HTCGC) methods for studying both these aspects of the chemistry of HMW hydrocarbons. In addition those hydrocarbons which remain unresolved when analysed by gas chromatography (so called unresolved complex mixtures UCMs) are also studied. UCMs may account for a large portion of the hydrocarbons in many fossil fuels yet very little is known about their composition. Knowledge of these compounds may be important in enhancing the prediction of phase behaviour. Oxidative degradation and GC-MS is used to elucidate the types of structures present within the UCM. The concentrations of C3S4h. ydrocarbons in two unusually waxy gas condensates from high temperature wells in the North Sea were determined by HTCGC. The whole C, 5+ fraction comprised about 20% of the total hydrocarbons and consisted of compounds with carbon numbers extending up to and beyond Coo. By paying particular attention to sample dissolution and injection, good reproducibility and precision were obtained. For example, for authentic n-C, to n-C60 alkanes a relative standard deviation of under 5% for manual injection, linear response factors (1.01 Cm to 0.99 C6), and a linear calibration for 5 ng to 25 ng on-column were found. Limits of detection are reported for the first time for HMW n-alkanes. The limits were found to be as low as 0.8 ng for Cto to 1.87 ng for C60. Tristearin is proposed as a suitable HTCGC internal standard for quantification since the FID response factor (1.1) was close to that of the HMW n-alkanes and response was linear. Importantly, when co-injected with the two waxy North Sea condensates, tristearin was adequately separated from the closest eluting alkanes, n-C59 and n-C60 under normal operating conditions. Qualitative characterisation of the HMW compounds in the waxy gas condensates and in synthetic wax blends (polywax 1000) using HTCGC-EI MS and HTCGC-CI MS produced molecular ions or pseudo molecular ions for n-alkanes up to n- C6o. The spectra of some HMW compounds contained fragment ions characteristic of branched compounds but detailed characterisation was very limited. This study has also shown, for the first time, the significance of the unresolved complex mixture in gas condensatesU. CM hydrocarbonsa ccountedf or over 20% of the total hydrocarbons in a waxy North sea condensateT. he condensatew as first distilled and the distillate UCMs isolated. Thesew ere found to be between 64 to 97 % unresolved after molecular sieving (5A) and urea adduction. The UCMs were oxidised using CrO3/AcOHw hich produced5 -12% C02, and 55-83% dichloromethane-solublep roducts. Thus 65-94% of the original UCMs were accounted for as oxidation products. The remainder were thought to be water soluble acids which could not be determined in the presence of the AcOH reagent. Of the recovered oxidised products, 27- 81 % were resolved and these comprised mainly n-monocarboxylic acids (19-48 %). The average chain length was found to be C12 indicating the average length of alkyl groups. Branched acids, ketones, ketoacids, ndicarboxylic acids, branched dicarboxylic acids, lactones, isoprenoid acids, alkylcyclohexane carboxylic acids and toluic acids accounted for the majority of the remaining resolved products. The distillate UCMs all showed variations in amountso f productsb ut not in composition. Retro-structurala nalysis suggestedth at the UCM in the gasc ondensatew as mainly aliphatic and branched.T he numbero f isomerso f simple brancheda lkaneso ver the UCM molecular weight range (determined by cryoscopy) was calculated to be over 15000. Overall, oxidation provided structural information for about half of the UCM. HTCGC was also used to measure the biodegradability of HMW alkanes in a waxy Indonesian oil. Traditional alkane isolation techniques (TLC and CC) discriminated against HMW compounds above C40 whereas adsorption onto alumina in a warm cyclohexane slurry provided an aliphatic fraction still rich in HMW compounds and suitable as a biodegradation substrate. A waxy Indonesian oil was subjected to 136 day biodegradation by Pseudomonas fluorescens. Extraction efficiencies of over 90 % (RSD <5 %) were obtained for n-alkanes up to C6o using continuous liquid-liquid extraction. Over 80 % of the oil aliphatic fraction was degraded within 14 days. After 136 days only 14% of the original aliphatic fraction remained, yet surprisingly no decreases in the concentrations of compounds above C45 were observed. However, the use of a rapid screening biodegradation method proved conclusively that Pseudomonasfluorescens was capable of utilising n-alkanes up to C60 once the bacteria had acclimated to the HMW alkanes. This is the first report of bacterial utilisation of an n-alkane as large as C.

Sustainable Pavement Engineering and Road Materials

In a similar way to many other engineering fields, the road pavement industry strongly affects the critical issues of our generation, including climate change, pollutant emission, the exploitation of natural resources and economic crises. For this reason, technicians and researchers are searching ravenously for sustainable solutions to implement in current road construction systems with the following goals: To reduce the consumption of energy and virgin materials; To run environmentally and economically friendly maintenance; To recycle waste from different industrial processes; To decrease the noise, the pollution and the heat generated by traffic, particularly in urban contexts. This Special Issue aims to collect high-quality studies that combine the aforementioned solutions, including works pertaining to: The hot, warm, and cold recycling of reclaimed asphalt pavement; Marginal materials for asphalt pavements; Innovative sustainable materials; Durability and environmental aspects; Structure performance, modeling and design; Advanced trends in rehabilitation and preservation; Surface characteristics and road safety; Management system/life cycle analysis; Urban heat island mitigation; Energy harvesting

Intermediate filament protein assembly : a proteomic approach

Intermediate filament proteins (IFPs) form the main structural elements of a wool fibre. The IFPs of wool are comprised of two families; the acidic type I family and the neutral-basic type II family. During follicle development, one type I and one type II IFP develop into an obligate heteropolymer, which, through a series of associations with other heteropolymers, forms an intermediate filament. Two-dimensional polyacrylamide gel electrophoresis (20-PAGE) methods have been used to provide high-resolution separation of wool IFPs. Improvements in the method for maintaining reducing conditions and chaotrope constitution, combined with low % T polyacrylamide gels, allowed the high-resolution separation of the two keratin IFP families and their individual family members. The IFPs were separated to produce a clearly defined spot pattern, with numerous discrete minor spots not previously observed. Genomic studies have reported that there are eight genes which produce eight abundant IFPs in wool. It was hypothesised that the large number of additional spots seen on a 20-PAGE gel was due to post-translational modification (PTM) of the protein. Several common PTMs of proteins produce charge heterogeneity, including phosphorylation and glycosylation. However, analysis of wool IFPs by 20- PAGE techniques and mass spectrometry revealed no evidence of phosphorylation or glycosylation modifications. Conformational equilibria as a cause of protein charge heterogeneity has recently been reported. Investigations with both the type I and type II IFPs have shown that when single protein spots from a 20-PAGE separation are eluted, re-focused and re-electrophoresed, several spots are formed on both the acidic and basic side of the original spot. The cause of this heterogeneity is thought to be a conformational equilibrium between several different forms of the same protein in the rehydration solution used for the first dimension. This technique allowed the accurate assignment of IFPs resolved by 20-PAGE to protein families. Fractionation methods to separate the IFPs and intermediate filament associated proteins (IFAPs) were successfully developed. Further fractionation into the type I and type II IFPs was achieved along with partial success at isolating individual spots. In vitro assembly experiments with the different IFP families gives important information about the strength of different protein pairings. To date there are no reproducible, efficient, in vitro assembly conditions for keratinised wool IFPs. A comprehensive study to investigate assembly conditions for keratinised wool IFPs was undertaken. Assembly of filaments from IFPs was achieved after a partial digestion with chymotrypsin. Filaments were formed that varied in diameter from 10 to 40 nm, showing that higher ordered structures were being formed. This demonstrates that IFPs can be successfully assembled in vitro to form filamentous structures that may be able to be manipulated for biomaterial uses