No description available.

No description available.

No description available.

The City of Saskatoon (COS) manages diverse road infrastructure assets. Given the present day challenges of structurally upgrading in-service road infrastructure assets in diverse field state conditions, there is a need to incorporate new innovative materials, changing field state conditions, and mechanistic design methods in sustainable road rehabilitation decision making. The COS is faced with challenges including rising material and labour costs, budget shortfalls, depleting virgin aggregate sources in close proximity to the COS, and an increase in stockpiled asphalt and concrete rubble materials due to transportation infrastructure renewal. As a result of the COS impact crushing program, a need to determine the design and performance properties of using recycled reclaimed asphalt concrete (RAP) rubble materials in urban pavement structures was established. RAP materials had never been used as a structural base layer in COS pavement structures because no material characterization had been conducted and there was no performance information with regards to their structural behaviour and field performance available. Other jurisdictions documented benefits of using recycled RAP in road structure include: reduced demand on depleting aggregate sources; reduced energy consumption; diversion of stockpiled RAP materials from landfills; and reduced overall handling and disposal costs. Given the amount of crushed RAP material available to the COS, it was determined there are potential benefits to implementing the use of recycled crushed RAP rubble in pavement structures, leading to the implementation of the “Green Street” Infrastructure Program. The findings of this research indicate that RAP materials have improved mechanistic properties compared to conventional granular materials; therefore, RAP materials can be used as a base layer in a road structure. This research indicates that cement stabilization and cement with a slow setting (SS-1) emulsion stabilization improved the moisture susceptibility of well graded (GW) and open graded base course (OGBC) RAP materials. These findings demonstrated that RAP materials stabilized with cement and/or SS-1 emulsion can be used as a base layer in a pavement structure. This research also found that the standard Proctor compaction method is not applicable for RAP materials to quantify moisture-density behaviour under compaction, due to the bound-nature of RAP aggregates, which are composed of asphalt and aggregate. California bearing ratio (CBR) values of Proctor-compacted RAP specimens did not accurately reflect field performance observations. As part of the COS “Green Street” Infrastructure Program, two test sections using crushed GW RAP rubble materials as a base layer were constructed as part of this research and include Marquis Drive (eastbound lanes from Thatcher Avenue to Idylwyld Drive) and 8th Street East (westbound lanes from Boychuk Drive west 0.540 kilometers). Test sections were constructed by the City of Saskatoon with conventional construction equipment and showed structural improvement in structural performance and visual distresses. Using RAP materials as a base layer was economically feasible because the RAP material cost less than conventional virgin aggregate base materials. This research demonstrates that processed and crushed RAP rubble materials are technically feasible to be used as a structural base layer in a recycled pavement structural system for urban road rehabilitation systems, and provide economic benefits over conventional granular base materials.

Asphalt pavement rutting is one of the most commonly observed pavement distresses and is a major safety concern to transportation agencies. Millions of dollars are reportedly spent annually to repair rutted asphalt pavements. Research into improvements of hot-mix asphalt materials, mix designs and methods of pavement evaluation and design, including laboratory and field testing, can provide extended pavement life and significant cost savings in pavement maintenance and rehabilitation. This research describes a method of predicting the behaviour of various asphalt mixes and linking these behaviours to an accelerated performance testing tool and pavement in-situ performance. The elastic, plastic, viscoelastic and viscoplastic components of asphalt mix deformation are also examined for their relevance to asphalt rutting prediction. The finite element method (FEM) allows for analysis of nonlinear viscoplastic behaviour of asphalt mixes. This research determines the critical characteristics of asphalt mixes which control rutting potential and investigates the methods of laboratory testing which can be used to determine these characteristics. The Hamburg Wheel Rut Tester (HWRT) is used in this research for asphalt laboratory accelerated rutting resistance testing and for calibration of material parameters developed in triaxial repeated load creep and creep recovery testing. The rutting resistance criteria used in the HWRT are developed for various traffic loading levels. The results and mix ranking associated with the laboratory testing are compared with the results and mix ranking associated with FEM modeling and new mechanistic-empirical method of pavement design analyses. A good relationship is observed between laboratory measured and analytically predicted performance of asphalt mixes. The result of this research is a practical framework for developing material parameters in laboratory testing which can be used in FEM modeling of accelerated performance testing and pavement in-situ performance.

Call number: LD2668 .T4 1950 Z54 / Master of Science

El Stone Mastic Asphalt, SMA, diseño de origen alemán desarrollado en los años 60 ha permitido dar solución a los problemas de tránsitos pesados y climas fríos, de las carreteras en Europa, EE.UU. y Canadá y recientemente en Brasil y Argentina. El concepto de diseño SMA se basa en una estructura granular donde predomina el contacto piedra-piedra el mismo que le provee de alta resistencia cortante, baja deformación permanente o “rutting” y considera un buen porcentaje de ligante que le confiere una excelente durabilidad.

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.

Asphalt concrete mix design methods, such as the Marshall method, have historically been based on physical and phenomenological material testing empirically correlated to observed field performance. Changing pavement field state conditions such as increased trucking, poorer quality aggregate resources, and the aged state of road infrastructure in Saskatchewan have resulted in recent pavement performance to be outside traditional empirical performance prediction inference. <p>It has been recognized worldwide that a mechanistic based asphalt concrete mix design methodology that directly quantifies structural behaviour of pavement under diverse field state conditions could significantly assist pavement design engineers. However, SHRP Level II and III mechanistic asphalt concrete characterization has been shown not to be pragmatic for characterizing asphalt concrete mixes. <p>The objective of this research was to investigate the use of mechanistic material properties obtained from triaxial frequency sweep characterization in the rapid triaxial tester (RaTT) in conjunction with SHRP gyratory compaction properties for designing asphalt concrete for different asphalt cement contents, traffic loads, traffic speeds, and temperatures. <p>RaTT testing was more responsive to variation in asphalt cement content outside of acceptable ranges of volumetric properties relative to Marshall stability and flow. This demonstrated the importance of specifying acceptable volumetric properties of asphalt concrete mixes. Correlation of material properties with volumetric measurements validated triaxial frequency sweep characterization in the RaTT. Dynamic modulus, Poissons ratio, and phase angle results were in accordance with expected material behaviour, indicating that the RaTT provides reasonable asphalt concrete material properties. Also, the RaTT identified asphalt concrete to be a nonlinear viscoelastic material, as observed in the field. <p>The RaTT was able to characterize SHRP gyratory compacted samples for the typical range of traction states, load frequencies, and temperatures that simulated a range of Saskatchewan field state conditions. Triaxial frequency sweep testing in the RaTT could significantly augment conventional volumetric mix analysis as well as the SHRP SuperpaveTM Level I asphalt concrete mix design system. RaTT testing was found to be cost effective, time efficient, and provided mechanistic material constitutive relations that can be employed for inelastic mechanistic mix design, road structural modelling, and asset management.

Asphalt concrete mix design methods, such as the Marshall method, have historically been based on physical and phenomenological material testing empirically correlated to observed field performance. Changing pavement field state conditions such as increased trucking, poorer quality aggregate resources, and the aged state of road infrastructure in Saskatchewan have resulted in recent pavement performance to be outside traditional empirical performance prediction inference. <p>It has been recognized worldwide that a mechanistic based asphalt concrete mix design methodology that directly quantifies structural behaviour of pavement under diverse field state conditions could significantly assist pavement design engineers. However, SHRP Level II and III mechanistic asphalt concrete characterization has been shown not to be pragmatic for characterizing asphalt concrete mixes. <p>The objective of this research was to investigate the use of mechanistic material properties obtained from triaxial frequency sweep characterization in the rapid triaxial tester (RaTT) in conjunction with SHRP gyratory compaction properties for designing asphalt concrete for different asphalt cement contents, traffic loads, traffic speeds, and temperatures. <p>RaTT testing was more responsive to variation in asphalt cement content outside of acceptable ranges of volumetric properties relative to Marshall stability and flow. This demonstrated the importance of specifying acceptable volumetric properties of asphalt concrete mixes. Correlation of material properties with volumetric measurements validated triaxial frequency sweep characterization in the RaTT. Dynamic modulus, Poissons ratio, and phase angle results were in accordance with expected material behaviour, indicating that the RaTT provides reasonable asphalt concrete material properties. Also, the RaTT identified asphalt concrete to be a nonlinear viscoelastic material, as observed in the field. <p>The RaTT was able to characterize SHRP gyratory compacted samples for the typical range of traction states, load frequencies, and temperatures that simulated a range of Saskatchewan field state conditions. Triaxial frequency sweep testing in the RaTT could significantly augment conventional volumetric mix analysis as well as the SHRP SuperpaveTM Level I asphalt concrete mix design system. RaTT testing was found to be cost effective, time efficient, and provided mechanistic material constitutive relations that can be employed for inelastic mechanistic mix design, road structural modelling, and asset management.