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Polyurethane network binders were synthesized using polyethylene glycol (PEG) prepolymers, cellulose acetate butyrate (CAB), curative [Desmodur N100 (N100) or Desmodur N3200 (N3200)], and catalyst [dibutyltin dilaurate (DBTDL)]. Triacetin (TA) was added as plasticizer before the reaction. Polyurethanes were prepared by varying the molar ratio of ¡VNCO/-OH, weight ratio of TA/PEG, molecular weight of PEG, the amount of catalyst, the order of adding catalyst and curative, and the stirred time. Synthesized polyurethanes were characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), tensile tests, and swelling tests to study their reaction, degradation, thermal, and mechanical properties. When the ratio of ¡VNCO/-OH was between 1.2 and 1.4, polyurethane gave the best mechanical properties. Additionally, the quenched polyurethane had a lower degree of crystallinity When the weight ratio of TA and PEG was bigger than 2, crystallization of polyurethane could be minimized during the tensile testing or after quenching. In this study, it was found that PEG with molecular weight of 4000 yielded the best mechanical properties. These results indicate that better and uniform mechanical properties can be obtained by using enough stirring time via varying the amount of catalyst and adding catalyst before curing agent.

The primary objective of this thesis was to develop a nucleation regime map to determine the controlling nucleation mechanism as a function of material properties and operating parameters. Two distinct regimes of nucleation were identified. The drop controlled nucleation regime occurs when nucleation conditions are ideal and one drop produces one nucleus granule and the controlling property is the droplet size. The nuclei formation kinetics are fast and the binder droplets penetrate into the powder bed pores almost immediately. In this region, the nuclei distribution reflects the drop size distribution as one drop tends to form one granule provided that (a) drops hitting the powder surface do not overlap - low spray flux Ya and (b) the drop must wet into the bed completely before bed mixing brings it into contact with another partially absorbed drop on the bed surface - low penetration time tp. If either criterion is not met, powder mixing characteristics will dominate. In the mechanical dispersion regime, the viscous or poorly wetting binder is slow to flow through the powder pores and form nuclei and good mixing is required for binder dispersion. The kinetics of nuclei formation were characterised using a simple drop penetration time test. A single drop of binder fluid was placed on a loosely packed powder bed and the time taken for the fluid to penetrate completely was measured for a range of powder and binder combinations. Loosely packed powder beds contain large macrovoids which are included in the existing Kozeny approach to estimating pore size. However it was found that these pores do not participate in liquid flow. A new two phase model was proposed where the total volume of the macrovoids was assumed to be the difference between the bed porosity and the tap porosity. A new parameter, the effective porosity eeff, was defined as the tap porosity multiplied by the estimated fraction of pores that terminate at a macrovoid and are effectively blocked pores. The pore sizes and drop penetration times were recalculated using the effective porosity and the predicted tp values were generally within an order of magnitude of the experimental results for all powders. The drop penetration time is reduced by small drops, low viscosity fluids, porous powders (but without macrovoids), large powder pores, high surface tension, low contact angle and pre-wetting of the powder bed. A new dimensionless group, the dimensionless spray flux Ya was defined to characterise the three most important operating variables in binder dispersion: liquid binder flowrate, drop size and powder flux through the spray zone. At low Ya, the majority of drops land on the powder sufficiently well separated to allow ideal “drop controlled” nucleation where one drop forms one granule. As Ya increases, the probability of drop footprints overlapping to give larger agglomerate nuclei increases. Monte-Carlo simulations were performed to validate the spray flux theory. The proportion of nuclei formed from single drops falls exponentially as Ya increases and to remain in the drop controlled regime Ya must be kept below 0.1. Analytical solutions based on the Poisson distribution for the fraction of single drop nuclei as a function of Ya were an excellent match with the Monte-Carlo data. Further validation experiments in carefully designed ex-granulator experiments and in an industrial granulator were performed. The results matched the theoretical solutions and demonstrated the ability of Ya to describe the nucleation zone in a real granulator. The proposed nucleation regime map demonstrated the interaction between drop penetration time and spray flux in nucleation. At short penetration times, such as the water and lactose system, decreasing Ya causes a shift towards the drop controlled regime and a narrower nuclei distribution. When penetration time is long, the nuclei size distribution is always larger and broader. Granulation may still be successful if the mechanical dispersion forces are able to break up the binder clumps and distribute the binder through the powder. The nucleation regime map should prove to be a useful tool for maintaining effective liquid distribution during scale-up as well as a useful trouble-shooting tool. It allows the dominant mechanism controlling the nucleation process to be easily identified using relatively simple parameters and a rational approach can then be used to control the properties of the nuclei.

Atlantic Canadian highways are vulnerable to impacts of climate change, including more frequent cycles of both wetting and drying, and freezing and thawing. These climate impacts coupled with continued increases in truck traffic can cause more severe and premature permanent deformation at high service temperature, fatigue and thermal cracking at low service temperatures, surface wear resistance, and ageing of the pavement. Such negative impacts can be mitigated with changes to the binder. However, replacing a local binder with a different imported binder can increase construction costs and cause supply problems. Alternatively, modifying agents can be used to adjust binder properties as required, but can also cause an increase in construction costs mainly due to their high cost and the need for highly specialized production techniques. The objective of this research project was to investigate the feasibility of utilizing underutilized household and packaging recycled plastics, that are generated in Atlantic Canada, as more cost effective alternatives or as co-modifiers to displace the amount of virgin modifiers used in hot mix asphalt application. The research study entailed analyzing physical characteristics of an array of modified binders and hot mix asphalt mixtures containing recycled low-density polyethylene, recycled polystyrene and the typical engineered virgin modifier (styrene-butadiene-styrene). The analysis included tests used commonly in pavement engineering to evaluate binders and asphalt mixtures. Results of this study suggests that these recycled plastics can be successfully utilized in asphalt binder as modifiers to enhance the functional properties of the mixture and reduce construction costs, thus creating an engineered value-added application of these underutilized resources as opposed to a disposal mechanism.

The desire to find more sustainable paving practices as well as the dramatically rising binder costs driven by the growing global demand for paved roads, has led to increased interest of the use of reclaimed asphalt pavement (RAP) in very high amounts. So far the major industry trend has been to develop procedures, invest in technologies and build confidence in mixtures with up to 40 % RAP content. However, a few innovators have refined 100 % recycling technologies over the past four decades to a level where routine production of 100 % recycled hot mix asphalt is in clear sight. Rejuvenators are an integral part of 100 % recycled asphalt production and they can also allow to significantly increase the RAP content for conventionally produced asphalt mixtures. An evaluation of the feasibility of production of 100 % recycled hot-mix asphalt was made and the use of rejuvenators is presented in this study. 100 % recycling is discussed by evaluating ten readily available production technologies along with proposing mix design procedures and identifying best RAP management strategies. A total of eleven different products were evaluated for restoring the RAP binder grade with a definite conclusion that achieving target grade (PG or empirical specification) is possible. In addition a rheological, micromechanical and chemical characterization was performed with select rejuvenators and binders from Strategic Highway Research Program (SHRP) library. To further assess the rejuvenators and feasibility of 100 % RAP recycling a series of 100 % mixture tests were performed that indicated significant improvement in low temperature and fatigue cracking resistance while providing a rut resistant mixture. With the use of some rejuvenators a performance equal to that of reference virgin mix was achieved. Based on these findings of rejuvenator effectiveness a methodology for choice of rejuvenator type and dose was proposed. Finally, a cradle-to-gate analysis of environmental effects was performed which indicated 35 % CO2eq savings per ton of produced 100 % RAP asphalt mixture compared to virgin mix while cost analysis showed at least 50 % savings in material related expenses. A short video summarizing the research is available at http://youtu.be/y-rYvdGiEbY.

Alkali-activated binders (AABs) are the third-generation class of binders after lime and Portland cement. These binders have the potential to be made from a variety of industrial waste sources, many of which have remained largely unexplored. Significant drawbacks of AABs are the requirement of highly alkaline solutions for its production and the lack of available data regarding its implementation in the field. To bridge this gap, this study aimed to research the recycling and valorization of tungsten mining waste (TMW) to produce AABs, using waste glass (WG) as a supplementary material for reducing the alkali activator demand. Finally, a connection was made between the fundamental research on AABs and a practical engineering application. A detailed approach was undertaken to determine the most appropriate TMW-WG AAB preparation methods and curing conditions, an understudied area, with a strong emphasis on the microstructural development during hardening. The alkali activator appeared to be sensitive to prolonged stirring, which appeared to induce a stripping effect of the water molecules from the alkali metal ions, leading to a less intense attack on the silicon-oxygen bonds in precursor material. The effects of WG (dissolution and chemical reaction) were investigated to understand its contribution to the AAB system. WG was observed to provide an additional source reactive silica, contributing to the formation of a calcium-containing N-A-S-H gel, and significantly improve the mechanical strength. PCM macro-encapsulated aggregates (ME-LWAs) were also researched and incorporated into the TMW-WG AAB for the development of an energy-saving building material. The ME-LWAs stood out to be leak proof, with excellent thermal stability and thermal conductivity, latent heat capacity and abrasion resistance. It was also found out it is feasible to produce foamed lightweight alkali-activated materials using tungsten mining waste (TMW-WG FAAB) and other precursor materials. FAAB can be used in several applications where low density and fire resistance is required. The TMW-WG FAAB was also designed to suit a wide range of densities and compressive strengths using chemical foaming, achieving very low thermal conductivity. Finally, the TMW-WG AAB proved itself to be convenient to prepare on-site, demonstrating in service its ease of preparation, rapid hardening and durability as a novel road repair mortar.

Zeolites ZSM-5 (SiO2/Al2O3=30~280) and Y(SiO2/Al2O3=5.2~80) are bound with silica gel (Ludox HS-40 and Ludox AS-40) and alumina (γ- Al2O3 and boehmite) by different binding methods, namely, gel-mixing, powder-mixing and powder-wet-mixing methods. The acidities of the bound catalysts and the zeolite powder are determined by NH3-TPD and FTIR. The textures of these catalysts are analyzed on a BET machine with nitrogen as a probe molecule. The micropore surface area and micropore volume are determined by t-plot method. Micropore volume distribution is determined by Horvath-Kawazoe approach with a cylindrical pore model. Mesopore volume distribution is determined by BJH method from the nitrogen desorption isotherm. Silica from the binder may react with extra-framework alumina in zeolites to form a new protonic acid. SiO2-bound catalysts have less strong acidity, Bronsted acidity and Lewis acidity than the zeolite powder. Also, the strength of strong acid sites of the zeolites is reduced when silica is embedded. Micropore surface area and micropore volume are reduced by about 19% and 18%, respectively, indicating some micropores of ZSM-5 are blocked on binding with silica. SiO2-bound ZSM-5 catalysts have less catalytic activity for butane transformation (cracking and disproportionation) and ethylene oligomerization than ZSM-5 powder. When alumina is used as a binder, both the total acid sites and Lewis acid sites are increased. Micropore surface area and micropore volume of ZSM-5 powder are reduced by 26% and 23%, respectively, indicating some micropores of ZSM-5 are blocked by the alumina binder. Alumina-bound catalysts showed a lower activity for butane transformation and ethylene oligomerization than ZSM-5 powder. Alkaline metals content in the binder is a crucial factor that influences the acidity of a bound catalyst. The metal cations neutralize more selectively Bronsted acid sites than Lewis acid sites. Alkaline metal cations in the binder and micropore blockage cause the bound catalysts to have a lower catalytic activity than the zeolite powder.

The main objective of this research was to investigate possible uses of Western-Canadian grown chickpea (<i>Cicer arietinum</i> L.) in the form of flour, starch and protein isolates in low-fat pork bologna. <p>In the first study, flour, starch and protein isolates from six chickpea cultivars (three Kabuli and three Desi) from two harvests (2005 and 2006) were evaluated for their physico-chemical, functional and thermal properties. Chickpea flour was made by grinding seed to pass through a 0.1mm screen, whereas protein isolates and starch were prepared by a wet milling process. Protein isolates were prepared from chickpea flour (23.2% protein on average) by alkaline extraction (pH 8.0) and isoelectric precipitation (pH 4.3). Protein isolates contained 72.8-85.3% protein; the starch fraction contained 93.0-98.0% starch. On SDS-PAGE, the chickpea flours and protein isolates contained similar polypeptide bands in the range of 30 to 55 kDa, with three major bands at approximately 50-55, 40 and 30 kDa. Least gelation concentration (LGC) for chickpea flours ranged from 6-14%; LGC for chickpea protein isolates ranged from 10-14%. Differential scanning calorimetry (DSC) of chickpea flour slurries revealed two endothermic peaks. One corresponded to starch gelatinization at approximately 64°C, which was slightly higher than for the starch fraction (~60°C). The second broad peak at approximately 96°C corresponded to the denaturation of the globulin protein fraction, which was also slightly higher than for the protein isolates (~91°C). Chickpea flour exhibited nitrogen solubility index values higher than those of chickpea protein isolates and soy and pea protein isolates. Chickpea protein isolates exhibited water holding capacities, oil absorption capacities, emulsion activity indeces and emulsion stability indeces higher than those of the chickpea flours. CDC Xena (Kabuli) and Myles (Desi), in general, most exhibited properties appropriate for meat applications. In the second study, the efficacy of flour, starch and protein from CDC Xena (Kabuli hereafter) and Myles (Desi hereafter) were investigated in low-fat pork bologna (LFPB). Low-fat pork bologna (<5% fat) was prepared by incorporating 2.5 or 5.0% flour, 1.5 or 3.0% protein isolate (protein basis), or 1.0 or 2.0% starch in the formulation. Controls were prepared without any binder, and formulations containing wheat or pea flour, soy or pea protein isolate, potato or pea starch, or extra meat were prepared for comparison. Inclusion of chickpea flour, protein or starch had a positive effect (P<0.05) on the cook yield, expressible moisture and purge of LFPB, and had little effect on colour. Increasing chickpea flour substitution from 2.5 to 5.0% altered the sensory and instrumental textural quality of LFPB significantly (P<0.05). Desi flour at 5.0% showed the highest TPA (texture profile analysis) hardness and chewiness, Allo-Kramer shear values and torsion shear stress. Similarly, LFPB containing chickpea protein isolate (CPI), soy protein isolate (SPI) or pea protein isolate (PPI) (3.0% protein basis) was firmer than either LFPB containing 1.5% protein from CPI, SPI or PPI or the control-I (with the same level of meat protein). Likewise, LFPB formulated with 2.0% Kabuli or Desi starch had higher TPA values than those prepared with pea or potato starch. For most flavour sensory properties, Kabuli and Desi chickpea flour and starch, irrespective of level of incorporation, performed similarly to the control. However, panellists noted more off-flavours with the addition of wheat flour or pea flour at 5.0%. Chickpea protein isolate, SPI or PPI at the 1.5% protein addition level did not alter the flavour properties of LFPB.<p>It was concluded that chickpea flour, starch and protein had potential for utilization as extenders in low-fat meat emulsion systems such as frankfurters and bologna.

The main objective of this research was to investigate possible uses of Western-Canadian grown chickpea (<i>Cicer arietinum</i> L.) in the form of flour, starch and protein isolates in low-fat pork bologna. <p>In the first study, flour, starch and protein isolates from six chickpea cultivars (three Kabuli and three Desi) from two harvests (2005 and 2006) were evaluated for their physico-chemical, functional and thermal properties. Chickpea flour was made by grinding seed to pass through a 0.1mm screen, whereas protein isolates and starch were prepared by a wet milling process. Protein isolates were prepared from chickpea flour (23.2% protein on average) by alkaline extraction (pH 8.0) and isoelectric precipitation (pH 4.3). Protein isolates contained 72.8-85.3% protein; the starch fraction contained 93.0-98.0% starch. On SDS-PAGE, the chickpea flours and protein isolates contained similar polypeptide bands in the range of 30 to 55 kDa, with three major bands at approximately 50-55, 40 and 30 kDa. Least gelation concentration (LGC) for chickpea flours ranged from 6-14%; LGC for chickpea protein isolates ranged from 10-14%. Differential scanning calorimetry (DSC) of chickpea flour slurries revealed two endothermic peaks. One corresponded to starch gelatinization at approximately 64°C, which was slightly higher than for the starch fraction (~60°C). The second broad peak at approximately 96°C corresponded to the denaturation of the globulin protein fraction, which was also slightly higher than for the protein isolates (~91°C). Chickpea flour exhibited nitrogen solubility index values higher than those of chickpea protein isolates and soy and pea protein isolates. Chickpea protein isolates exhibited water holding capacities, oil absorption capacities, emulsion activity indeces and emulsion stability indeces higher than those of the chickpea flours. CDC Xena (Kabuli) and Myles (Desi), in general, most exhibited properties appropriate for meat applications. In the second study, the efficacy of flour, starch and protein from CDC Xena (Kabuli hereafter) and Myles (Desi hereafter) were investigated in low-fat pork bologna (LFPB). Low-fat pork bologna (<5% fat) was prepared by incorporating 2.5 or 5.0% flour, 1.5 or 3.0% protein isolate (protein basis), or 1.0 or 2.0% starch in the formulation. Controls were prepared without any binder, and formulations containing wheat or pea flour, soy or pea protein isolate, potato or pea starch, or extra meat were prepared for comparison. Inclusion of chickpea flour, protein or starch had a positive effect (P<0.05) on the cook yield, expressible moisture and purge of LFPB, and had little effect on colour. Increasing chickpea flour substitution from 2.5 to 5.0% altered the sensory and instrumental textural quality of LFPB significantly (P<0.05). Desi flour at 5.0% showed the highest TPA (texture profile analysis) hardness and chewiness, Allo-Kramer shear values and torsion shear stress. Similarly, LFPB containing chickpea protein isolate (CPI), soy protein isolate (SPI) or pea protein isolate (PPI) (3.0% protein basis) was firmer than either LFPB containing 1.5% protein from CPI, SPI or PPI or the control-I (with the same level of meat protein). Likewise, LFPB formulated with 2.0% Kabuli or Desi starch had higher TPA values than those prepared with pea or potato starch. For most flavour sensory properties, Kabuli and Desi chickpea flour and starch, irrespective of level of incorporation, performed similarly to the control. However, panellists noted more off-flavours with the addition of wheat flour or pea flour at 5.0%. Chickpea protein isolate, SPI or PPI at the 1.5% protein addition level did not alter the flavour properties of LFPB.<p>It was concluded that chickpea flour, starch and protein had potential for utilization as extenders in low-fat meat emulsion systems such as frankfurters and bologna.

Asphalt oxidation causes major changes to binder properties and is hypothesized to be a major contributor to age-related pavement failure such as fatigue cracking. Extensive laboratory aging research has been done to assess the effects of oxidation on binder properties. Previous work shows binder oxidation makes the binder stiffer and more brittle, leading to higher binder stresses under a given deformation. Failure occurs when these stresses exceed the strength of the binder. However, binder oxidation in pavements has not been studied in the same detail as laboratory aging of neat binders. The impact of binder oxidation on long-term pavement performance has been either underestimated or ignored. This research includes studies of binder oxidation in Texas pavements to compare the field aging with laboratory neat binder aging, the impact of binder oxidation on HMAC mixture aging and HMAC mixture fatigue performance, and fundamental rheological property changes of the binder and the mixture. Binder oxidation is studied in fifteen pavements from locations across Texas. Results indicate that unmodified binders in pavements typically oxidize and harden to a degree that exceeds generally accepted pavement aging assumptions. This hardening may also extend much deeper into the pavement than has been previously assumed or documented. Data suggest that pavements can oxidize at rates surprisingly uniform with depth once early oxidation occurs, and that these rates continue for an extended time. Laboratory-aged HMAC mixtures and binders were tested and analyzed for fatigue resistance and their rheological properties. Mixture aging shows the same aging mechanisms as neat binder aging. Both binder and mixture have a higher modulus with aging and a good rheological correlation. The decline in mixture fatigue life (determined using the calibrated mechanistic fatigue analysis approach with surface energy measurement) due to oxidation is significant. Pavement service life is dependent on the mixture, but can be estimated by a cumulative damage approach that considers binder oxidation and pavement loading rate simultaneously. The differences in expected pavement life arise from differences in the rate of binder stiffening due to oxidation and the impact of this stiffening on the decline of fatigue life.