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The purpose of this research was to investigate the effects of reclaimed asphalt pavement (RAP) content and cement content on the strength and durability of recycled aggregate base materials. Specifically, the unconfined compressive strength (UCS) and final dielectric value in the Tube Suction Test (TST) were measured in a full-factorial experimental design including five RAP contents, five cement contents, and three replicate specimens of each possible treatment. Specimen mixtures consisted of 0, 25, 50, 75, or 100 percent RAP and 0.0, 0.5, 1.0, 1.5, or 2.0 percent Type I/II Portland cement. Both the RAP and base materials were sampled from the I-84 pavement reconstruction project performed in Weber Canyon near Morgan, Utah, during the summers of 2004 and 2005. The laboratory testing procedures consisted of material characterizations, specimen preparation, and subjection of the specimens to strength and durability testing, and the data were evaluated using analysis of variance (ANOVA) testing. Both the RAP and base materials included in this research were determined to be non-plastic, and the AASHTO and Unified soil classifications for the RAP material were determined to be A-1-a and SM (well-graded sand with gravel), respectively, and for the base material they were A-1-a and SW-SM (well-graded sand with silt and gravel), respectively. The optimum moisture contents (OMCs) for the blended materials were between 5.6 and 6.6 percent, and maximum dry density (MDD) values were between 129.7 and 135.5 lb/ft3. In both cases, decreasing values were associated with increasing RAP contents. The results of the ANOVA performed on the UCS data indicate that UCS decreases from 425 to 208 psi as RAP content increases from 0 to 100 percent and increases from 63 to 564 psi as cement content increases from 0.0 to 2.0 percent. Similarly, the final dielectric value decreases from 14.9 to 6.1 as RAP content increases from 0 to 100 percent and decreases from 14.0 to 5.8 as cement content increases from 0.0 to 2.0 percent. With design criteria requiring 7-day UCS values between 300 and 400 psi and final dielectric values less than 10 in the TST, the results of this research suggest that milling plans should be utilized to achieve RAP contents in the range of 50 to 75 percent, and a cement content of 1.0 percent should be specified for this material. Cement contents less than 1.0 percent are not sufficient to stabilize the material, and greater cement contents may cause cracking. Because control of the actual cement content in the field depends on the contractor's equipment and skill, inspection protocols should be implemented during construction to ensure high-quality work. Additional recommendations are associated with the construction process. The specimens prepared in this research were compacted to relative densities of 100 percent using modified Proctor energy. Therefore, field compaction levels must approach these density values if the same material properties are to be achieved. In addition, all specimens tested in this study were cured at 100 percent relative humidity. Following compaction in the field, cement-treated layers should be moistened frequently during the first few days after construction or promptly sealed with a prime coat or wearing surface to ensure that the cement continues to hydrate. Variability in RAP and cement contents should also be minimized to achieve consistent material properties.

The use of recycled concrete material (RCM) as pavement base material is a promising but unproven technique for road rehabilitation and construction. A telephone survey conducted to investigate the state of the practice concerning RCM usage in Utah County revealed that RCM is infrequently used in this application due primarily to a lack of practical knowledge about the engineering properties of the material. Therefore, this research was aimed at evaluating the physical properties, strength parameters, and durability characteristics of both demolition and haul-back sources of RCM available in Utah County for use as pavement base material. The study included extensive laboratory and field testing. Laboratory tests included California bearing ratio (CBR), unconfined compressive strength (UCS), stiffness, freeze-thaw cycling, moisture susceptibility, abrasion, salinity, and alkalinity evaluations. Non-destructive testing was utilized in the field to monitor seasonal variation in stiffness of an RCM pavement base layer over a 1-year period. The testing included a dynamic cone penetrometer, ground-penetrating radar, a heavy Clegg impact soil tester, a soil stiffness gauge, and a portable falling-weight deflectometer. The laboratory testing indicated that the demolition material exhibited lower strength and stiffness than the haul-back material and reduced UCS loss after freeze-thaw cycling. However, the demolition material received a moisture susceptibility rating of good in the tube suction test, while the haul-back material was rated as marginal. Both materials exhibited self-cementing effects that led to approximately 180 percent increases in UCS over a 7-day curing period. Seven-day UCS values were 1260 kPa and 1820 kPa for the demolition and haul-back materials, respectively, and corresponding CBR values were 22 and 55. The field monitoring demonstrated that the RCM base layer was susceptible to stiffness changes due primarily to changes in moisture. In its saturated state during spring testing, the site experienced CBR and stiffness losses of up to 60 percent compared to summer-time values. RCM compares well with typical pavement base materials in many respects. Given the laboratory and field data developed in this research, engineers should be able to estimate the strength and durability parameters of RCM needed for pavement design.

Full-depth reclamation (FDR) is an increasingly common technique that is used to rehabilitate flexible pavements. Implementation of FDR on rehabilitation projects produces several desirable benefits. However, these benefits are not fully realized due to the fact that state department of transportation specifications typically limit the reclaimed asphalt pavement (RAP) content of pavement base material to 50 percent. The objective of this research was to evaluate the effects of RAP content, cement content, temperature, curing time, curing condition, and moisture state on the strength, stiffness, and deformation characteristics of cement-treated base (CTB) mixtures containing high percentages of RAP.For this research, one aggregate base material and one RAP material were used for all samples. RAP content ranged from 0 to 100 percent in increments of 25 percent, and low, medium, and high cement levels corresponding to 7-day unconfined compressive strength (UCS) values of 200, 400, and 600 psi, respectively, were selected for testing. Moisture-density, UCS, resilient modulus, and permanent deformation tests were performed for various combinations of factors, and several statistical analyses were utilized to evaluate the results of the UCS, resilient modulus, and permanent deformation testing.The results of this work show that CTB containing RAP can be made to achieve 7-day UCS values approaching 600 psi regardless of RAP content. With regards to stiffness, the data collected in this study indicate that the resilient modulus of CTB containing RAP is affected by temperature in the range from 72 to 140°F for the low cement level. Permanent deformation of CTB containing RAP is significantly affected by RAP content and cement level at the test temperature of 140°F. At the low cement level, temperature is also a significant variable. As the 7-day UCS reaches approximately 400 psi, permanent deformation is reduced to negligible quantities. The results of this research indicate that the inverse relationship observed between permanent deformation and 7-day UCS is statistically significant.Given that the principle conclusion from this work is that CTB with high RAP contents can perform satisfactorily as a base material when a sufficient amount of cement is applied, agencies currently specifying limits on the percentage of RAP that can be used as a part of reclaimed base material in the FDR process should reevaluate their policies and specifications with the goal of allowing the use of high RAP contents where appropriate.

The modulus of aggregate base layers in pavement structures can potentially be increased through the use of geogrid. However, methods for determining how much structural benefit can be expected from a given geogrid product have not been standardized. A laboratory testing protocol is therefore needed to enable evaluation, in terms of modulus or California bearing ratio (CBR), for example, of the degree of improvement that may be achieved by a given geogrid. Consequently, the objective of this research was to identify a laboratory test method that can be used to quantify improvements in structural capacity of aggregate base materials reinforced with geogrid. For this research, National Cooperative Highway Research Program Report 598 repeated load triaxial, American Association of State Highway and Transportation Officials (AASHTO) T 307 quick shear, and CBR testing protocols were used to test unreinforced and geogrid-reinforced aggregate base materials from northern Utah. Biaxial and triaxial geogrid were investigated in multiple reinforcement configurations. Several statistical analyses were performed on the results of each test method to identify the test that is most likely to consistently show an improvement in the structural capacity of aggregate base materials reinforced with geogrid. The results of this research indicate that, for the methods and materials evaluated in this study, calculation of the modulus at 2 percent strain from the AASHTO T 307 quick shear data is the test method most likely to consistently show an improvement in structural capacity associated with geogrid reinforcement. Of the three configurations investigated as part of this research, placing the geogrid at an upper position within a specimen is preferred. Given that the end goal of the use of geogrid reinforcement is to improve pavement performance, additional research is needed to compare the results of the AASHTO T 307 quick shear test obtained in the laboratory with the structural capacity of geogrid-reinforced aggregate base materials measured in the field. In addition, correlations between the results of the AASHTO T 307 quick shear test and resilient modulus need to be investigated in order to incorporate the findings of the AASHTO T 307 quick shear test on reinforced base materials into mechanistic-empirical pavement design.

As the world’s population is migrating more into urban areas, landcover changes follow. Natural pervious areas are being converted to impervious areas, which when subjected to rain generates more stormwater runoff. Stormwater management is a problem that cities today are challenged with, infrastructure is getting older and precipitation patterns are changing due to climate change. Due to climate change extreme precipitation events are likely to increase and therefore increase the probability of urban flooding. Urban flooding can be caused by extreme precipitation events with a short duration, or so-called flash floods. These flash floods can overwhelm the drainage system in place which therefore can cause flooding. This problem has inspired engineers to rethink stormwater management, moving from traditional grey drainage systems to more green and sustainable drainage systems. Sustainable Urban Drainage System (SuDS) are drainage systems that aim to regain the properties of non-urbanised areas, retain the natural hydrological cycle, and have recreational values for the surrounding societies. This study investigated how different SuDS behave when subjected to flash floods. A model of a synthetic case study was built in the Storm Water Management Model (SWMM) and sustainable urban drainage systems implemented. The solutions investigated were bioretention cells, rain gardens, infiltration trenches, green roofs, and permeable pavements. Three different rain events were analysed, all with different precipitation depth but with the same duration of 1 hour. Results showed that bioretention cells could reduce runoff volumes to the highest extent while green roofs could reduce the peak runoff the most. Other results were analysed like efficiency and cost. Bioretention cell came out on top in efficiency but had the highest cost. Overall, all the solutions showed promise in reducing runoff during flash floods, but the reduction capacity goes down with increased precipitation. / När en större del av världens befolkning flyttar in till tätortsområden så medföljer en ändring av markytans beskaffenhet. Vanligtvis genomträngliga ytor omvandlas till hårdgjorda ytor vilket generar mer dagvattenavrinning när de utsätts för regn. Dagvattenhanteringen är en utmaning för många städer idag eftersom infrastrukturen blir äldre och nederbördsmönstren förändras på grund av klimatförändringar. Extrema nederbördshändelser väntas öka med anledning av dessa klimatförändringar och ökar därigenom sannolikheten för översvämningar i städer. Översvämningar i städer kan orsakas av korta nederbördshändelser med hög intensitet, så kallade Skyfall, vilket kan överbelasta dagvattensystemets kapacitet. Det har lett till att ingenjörer ändrat sitt tankesätt på hur dagvatten ska hanteras och börjat gå från konventionella till mer gröna och hållbara dräneringssystem. Hållbar dagvattenhantering är dräneringssystem som syftar till att använda egenskaperna hos naturliga områden, behålla det naturliga hydrologiska kretsloppet och skapa rekreationsvärden för de omkringliggande samhällena. Denna studie har undersökt hur olika hållbara dräneringssystem beter sig när de utsätts för översvämningar. En modell på en syntetisk fallstudie byggdes i Storm Water Management Model (SWMM) där hållbara dräneringssystem implementerades i en urban miljö. Lösningarna som undersöktes var biofilterbäddar, regnträdgårdar, infiltrationsbäddar, gröna tak och permeabla trottoarer. Tre olika nederbördshändelser analyserades, alla med olika nederbördsmängder men med samma varaktighet på en timme. Resultaten visade att biofilterbäddar kunde minska avrinningsvolymerna i största grad medan gröna tak minskade ytavrinningen mest. Effektivitet och kostnad analyserades också. Där visade biofilterbäddarna högst effektivitet men hade den högsta kostnaden. Sammantaget visade det sig att alla lösningar var lovande vad gäller minskning av avrinning under översvämningar, men reduktionskapaciteten minskar med ökad nederbörd.

Stormwater runoff from urban areas is a major source of pollution to surface water bodies. The discharge of nutrients such as nitrogen and phosphorus is particularly damaging as it results in harmful algal blooms which can limit the beneficial use of a water body. Stormwater best management practices (BMPs) have been developed over the years to help address this issue. While BMPs have been investigated for years, their use has been somewhat limited due to the fact that much of the data collected is for specific applications, in specific regions, and it is unknown how these systems will perform in other regions and for other applications. Additionally, the research was spread across the literature and performance data was not easily accessible or organized in a convenient way. Recently, local governments and the USEPA have begun to collect this data in BMP manuals to help designers implement this technology. That being said, many times a single BMP is insufficient to meet water quality and flood control needs in urban areas. A treatment train approach is required in these regions. In this dissertation, the development of methodologies to evaluate the performance of two BMPs, namely green roofs and pervious pavements is presented. Additionally, based on an extensive review of the literature, a model was developed to assist in the evaluation of site stormwater plans using a treatment train approach for the removal of nutrients due to the use of BMPs. This model is called the Best Management Practices Treatment for Removal on an Annual basis Involving Nutrients in Stormwater (BMPTRAINS) model. The first part of this research examined a previously developed method for designing green roofs for hydrologic efficiency. The model had not been tested for different designs and assumed that evapotranspiration was readily available for all regions. This work tested this methodology against different designs, both lab scale and full scale. Additionally, the use of the Blaney-Criddle equation was examined as a simple way to determine the ET for regions where data was not readily available. It was shown that the methods developed for determination of green roof efficiency had good agreement with collected data. Additionally, the use of the Blaney-Criddle equation for estimation of ET had good agreement with collected and measured data. The next part of this research examined a method to design pervious pavements. The water storage potential is essential to the successful design of these BMPs. This work examined the total and effective porosities under clean, sediment clogged, and rejuvenated conditions. Additionally, a new type of porosity was defined called operating porosity. This new porosity was defined as the average of the clean effective porosity and the sediment clogged effective porosity. This porosity term was created due to the fact that these systems exist in the exposed environment and subject to sediment loading due to site erosion, vehicle tracking, and spills. Due to this, using the clean effective porosity for design purposes would result in system failure for design type storm events towards the end of its service life. While rejuvenation techniques were found to be somewhat effective, it was also observed that often sediment would travel deep into the pavement system past the effective reach of vacuum sweeping. This was highly dependent on the pore structure of the pavement surface layer. Based on this examination, suggested values for operating porosity were presented which could be used to calculate the storage potential of these systems and subsequent curve number for design purposes. The final part of this work was the development of a site evaluation model using treatment train techniques. The BMPTRAINS model relied on an extensive literature review to gather data on performance of 15 different BMPs, including the two examined as part of this work. This model has 29 different land uses programmed into it and a user defined option, allowing for wide applicability. Additionally, this model allows a watershed to be split into up to four different catchments, each able to have their own distinct pre- and post-development conditions. Based on the pre- and post-development conditions specified by the user, event mean concentrations (EMCs) are assigned. These EMCs can also be overridden by the user. Each catchment can also contain up to three BMPs in series. If BMPs are to be in parallel, they must be in a separate catchment. The catchments can be configured in up to 15 different configurations, including series, parallel, and mixed. Again, this allows for wide applicability of site designs. The evaluation of cost is also available in this model, either in terms of capital cost or net present worth. The model allows for up to 25 different scenarios to be run comparing cost, presenting results in overall capital cost, overall net present worth, or cost per kg of nitrogen and phosphorus. The wide array of BMPs provided and the flexibility provided to the user makes this model a powerful tool for designers and regulators to help protect surface waters.

There are various distresses arising from traffic loads and the surrounding environment to whichan asphalt pavement is subjected during its life span. The environment-associated damages aremore severe during winter when abundant moisture and freezing temperature are presentsimultaneously. Damage caused by frost heave is one of the important winter-related damagesresulting in severe cracks and bumpy road surfaces. Since the frost heave-induced cracks areusually wide, they can make the pavement more prone to other types of damage by leaving theopen space for water and moisture penetration. Simulating the response of the pavement whenit is subjected to frost heave is the aim of this licentiate thesis. Attaining this objective requirescoupling a frost heave model with a damage model representing the mechanistic behavior ofthe asphalt material. With regard to the brittle behavior of the asphalt at cold temperatures, aviscoelastic damage model for asphalt material is coupled with a thermomechanical frost heavemodel. The thermomechanical approach couples the physical processes involved in frost actioninside the soil. To elucidate more, in this method the thermal and mechanical fields are coupledby the porosity evolution function which implicitly takes into account the effect of the hydraulicfield. On the other hand, the continuum viscoelastic damage model for asphalt material isdeveloped within the infinitesimal strain context by applying the thermodynamical restrictionsof irreversible processes. The suggested framework was employed in different finite elementmodels to simulate damages caused by frost heave in asphalt pavements. The results indicatethat it predicts the damage distribution and evolution in the asphalt. Furthermore, it was shownthat the uneven frost heave and physical processes taking place in the soil during frost actionsuch as cryogenic suction force creation, porosity evolution, ice formation, etc., can also besimulated. / Det finns olika typer av påfrestningar som uppstår från trafikbelastningar och den omgivandemiljön som en asfaltbeläggning utsätts för under sin livslängd. De miljörelaterade skadorna ärallvarligare under vintern när fukt och kalla temperaturer är närvarande samtidigt. Skadororsakade av tjällyft är en av de allvarliga vinterrelaterade skadorna som resulterar i sprickor ochskadade vägsytor. Eftersom de tjällyftsinducerade sprickorna vanligtvis är breda kan de görabeläggningen mer utsatt för andra typer av skador genom vatten- och fuktinträngning. Syftetmed denna licentiatavhandling är att simulera beläggningens reaktion när den utsätts för tjällyft.För att uppnå detta mål krävs att en tjällyftsmodell kopplas till en skademodell somrepresenterar asfaltmaterialets mekanistiska beteende. När det gäller asfaltens spröda beteendevid kalla temperaturer, är en viskoelastisk skademodell för asfaltmaterial kopplad till entermomekanisk tjällyftsmodell. Det termomekaniska tillvägagångssättet kopplar de fysiskaprocesserna som är involverade i frostverkan inuti jorden. För att klarlägga detta mer, är determiska och mekaniska fälten kopplade med porositetsutvecklingsfunktionen som implicit tarhänsyn till effekten av det hydrauliska fältet. Å andra sidan är den kontinuumviskoelastiskaskademodellen för asfaltmaterial utvecklad inom det oändliga töjningssammanhanget genomatt tillämpa de termodynamiska begränsningarna av irreversibla processer. Det föreslagnaramverket användes i olika finita elementmodeller för att simulera skador orsakade av tjällyft iasfaltbeläggningar. Resultaten indikerar att den förutsäger skadefördelningen och utvecklingeni asfalten. Dessutom har det visat sig att det ojämna tjällyft och fysiska processer som äger rumi marken under frostpåverkan, såsom skapande av kryogen sugkraft, porositetsutveckling,isbildning, etc., också kan simuleras. / <p>QC 20221124</p>

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