Rehabilitation and strengthening of concrete structures with externally bonded FRP (Fibre Reinforced Polymers) has been a viable technique for at least a decade. The most common way to strengthen a structure is in flexure where thedesign normally follows traditional concrete design, with exceptions for control of bond and anchorage related to the FRP. The method is also used for strengthening in shear and torsion, as well as for strengthening of columns. An interesting and useful application is strengthening of slabs or walls without or with openings. In the latter situation, FRP sheets or plates are very suitable; not only because of their strength, but also due to the simplicity in theexecution in comparison to traditional steel girders or other lintel systems. Even though many benefits have been shown in the use of FRP strengthening of openings in practical applications, not much research have been presented in the scientific literature. In this licentiate thesis, the results from laboratory tests on strengthened slabs loaded with a uniformly distributed load are analyzed with analytical and numerical methods. The slabs with openings have been strengthened with CFRP (Carbon Fibre Reinforced Polymers) sheets and are compared to traditionally steel reinforced slabs, both with and without openings. The results from the tests show that slabs with openings can be strengthened with externally bonded CFRP sheets. The performance is, in comparison, even better than for traditionally steel reinforced slabs if bond failure can be avoided. The numerical and analytical evaluations are in good agreement with the experimental results. The case study presented in chapter 5, shows a practical design application of a courtyard deck strengthened with CFRP using epoxy bonded plates. It also points out the difficulties in retrofitting of existing structures. Since the information was inadequate when the original design was performed, an active design approach was used i.e. the design was changed when the true site conditions was revealed during the reconstruction work. / <p>Godkänd; 2005; 20061213 (haneit)</p>

To meet the future traffic demands there is a constant need of making the infrastructure moreeffective. This can be achieved by increasing the capacity and/or life length of traffic lines. Apart of the efforts to do this is increasing the load carrying capacity of the railway bridges sothat it is possible to allow heavier freight trains to pass the bridges.In this thesis the assessment of the load carrying capacity of a strengthened concrete troughrailway bridge, The Övik Bridge, with two spans in Örnsköldsvik, in northern Sweden, istreated. To investigate the ultimate behavior of the bridge a full scale load test up to failure wasperformed in 2006.At the loading test in Örnsköldsvik a steel beam was placed in the mid of one of the spans ofthe bridge. The failure was caused by pulling the steel beam downwards with cables whichwere anchored with injection into the drilled holes in the bedrock beneath the bridge.While the mechanism of a bending failure is commonly considered to be well investigated, thestructural models for the shear failure are still the object of intense research. The bottom sidesof the edge beams of the Örnsköldsvik Bridge were strengthened with Near Surface Mountedreinforcement (NSM) consisting of Carbon Fibre Reinforced Polymers (CFRP) to increase thebending capacity and in that way steer the bridge to failure in shear instead of bending.The material properties of the reinforcement were determined in tension tests. Concreteproperties were determined by testing drilled core samples. Displacements and deflections ofthe bridge, strains in concrete, steel and carbon fibre reinforcement were measured during thetest as a function of the increasing load.In this thesis the analysis of the failure of the bridge, structural models describing the behaviorand load carrying capacity are evaluated according to different design codes. Advanced finiteelement analysis is applied with both geometrical and material non-linearities included. Toverify the models used in codes and computer calculations the response of the bridge duringthe test is compared with the calculation results.The refined and calibrated FEM model is used to predict how high axle loads of a train theÖvik Bridge could have sustained. The Övik Bridge was designed in 1950’s for axle loads of20 ton. The calculations methods developed in this thesis show that the axle loads in the failurestate could have been increased at least up to 154 tons without strengthening and to 215 tonwith strengthening of the bridge slab with carbon fibre reinforcement bars with Af = 100 mm2c 150 mm using statistical mean values of loads and material properties in the calculations. / Bärförmågan hos en förstärkt betongbroIcke-linjär finit elementmodellering av en brottbelastningTillståndsbedömning av en järnvägstrågbro med två spann i Örnsköldsvik förstärkt med stänger av kolfiberarmerade polymerer (CFRP)För att möta de framtida krav som trafiksektorn står inför måste infrastrukturen effektiviseras. Detta kan bland annat uppnås genom att öka trafikledernas kapacitet och livslängd. En del av denna ambition består av att öka lastkapaciteten på järnvägsbroar så att man kan tillåta tyngre godståg att passera.I denna avhandling behandlas tillståndsbedömning av en förstärkt trågbro av armerad betong. Bron hade två spann och var belägen i Örnsköldsvik i Sverige. Ett fullskaleförsök utfördes år 2006 för att studera brons beteende under ökande last tills brott uppstod.Under testet i Örnsköldsvik placerades en stålbalk i mitten av brons ena spann. Brottet frambringades genom att stålbalken drogs neråt med kablar, som hade förankrats i berget med injektion under bron, så att lasten på bron ökade. Medan mekanismen för böjmoment allmänt anses vara väl utredd är olika modeller för bärförmågan för tvärkraft fortfarande föremål för intensiv forskning. För att undvika det icke-intressanta böjbrottet förstärktes kantbalkarna i underkanten med kolfiberarmering (CFRP) i form av stavar som limmades fast i utsågade slitsar (Near Surface Mounted reinforcement, NSM). På det viset styrdes bron till att få skjuvbrott istället för böjbrott.Materialegenskaper för betongen bestämdes med hjälp av utborrade cylindrar och för armeringen med dragprov. Förskjutningar och utböjningar av bron samt töjningar i betong, stål- och kolfiberarmering mättes under pågående test som funktion av den ökande lasten.Bron analyserades på flera sätt för att jämföra verklig bärförmåga med olika normer. Ickelinjära finita element har härvid använts för att utvärdera hur avancerade beräkningsverktyg kan beskriva det verkliga skeendet. Olinjäriteter har beaktats i såväl material som geometri. Den förfinade och kalibrerade FEM -modellen användes för att bedöma den maximala axellasten för tåg som Öviksbron skulle ha kunnat bära. Öviksbron dimensionerades på 1950- talet för axellaster på 20 ton. Beräkningsmodellerna utvecklade i avhandlingen visar att bron i brottstadiet hade kunnat klara axellaster på minst 154 ton utan den utförda förstärkningen och på 215 ton med förstärkningen av broplattan med kolfiberstänger med Af = 100 mm2 c 150 mm. Statistiska medelvärden av laster och materialparametrar har härvid använts i beräkningarna. / Godkänd; 2012; 20120425 (ysko); DISPUTATION Ämnesområde: Konstruktionsteknik/Structural Engineering Opponent: Docent Mario Plos, Institutionen för bygg- och miljöteknik, Chalmers Tekniska Högskola, Göteborg Ordförande: Professor Mats Emborg, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Tid: Onsdag den 30 maj 2012, kl 10.15 Plats: F1031, Luleå tekniska universitet

Repeated cyclic loading of reinforced concrete (RC) structures such as bridges can cause reduced service life and structure failure due to fatigue even when the stress ranges applied to the structural components are very low. These problems can be mitigated by using fiber-reinforced polymer (FRP) composites to increase the structures’ load carrying capacity and fatigue life or service life. Strengthening of this sort may be a suitable way to prolong the service life of concrete structures. FRP strengthening involves externally bonding a plate, sheet or rod of the strengthening material to the surface of the concrete member or placing the strengthening element in grooves cut into the member’s surface. The bonding of plates or sheets to the surface is often referred to as EBR (externally bonded reinforcement) whereas the placement of strengthening bars in grooves carved into the member’s surface is referred to as NSM (Near Surface Mounted) reinforcement. When this research project was initiated, it was not clear whether EBR or NSM strengthening was more effective at alleviating the effects of fatigue loading, and there were many aspects of their use that warranted further investigation. The main objectives of the work presented in this thesis were to study the behaviour of materials and structures under fatigue loading, to assess the structural challenges presented by fatigue loading of members strengthened with EBR plates or NSM bars, and to identify analytical models suitable for the design and analysis of FRP-strengthening elements and strengthened concrete members. The scientific approach adopted in this work is based on experimental fatigue loading tests of RC beams strengthened with EBR plates and NSM bars together with the development and assessment of analytical methods for describing the fatigue behaviour of tested strengthened beams and numerical models for predicting the behaviour of bond joints under fatigue loading. The analytical models were then verified against experimental results. The theoretical and experimental studies were supported by a state-of-the-art literature review that was conducted to gather existing knowledge concerning FRP strengthening of RC members and their fatigue behaviour at the material and structural levels / Godkänd; 2015; 20150218 (mohsal); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Mohammed Salih Mohammed Mahal Ämne: Konstruktionsteknik/Structural Engineering Avhandling: Fatigue Behaviour of RC Beams Strengthened with CFRP – Analytical and Experimental Investigations Opponent: Professor Pilate Moyo, Department of Civil Engineering, University of cape Town, South Africa Ordförande: Professor Björn Täljsten, Avd för byggkonstruktion och produktion, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Tid: Fredag den 27 mars 2015, kl 10.00 Plats: F1031, Luleå tekniska universitet

A great number of society's resources are invested in existing concrete structures, such as bridges, tunnels, different kind of buildings etc. All of these structures have both an expected function and an expected life span. However, both the function and the life span can be influenced by external factors, e.g. degradation and altered load situations. Further influencing aspects could be mistakes in design or during the construction phase. Repairing and/or strengthening these structures could maintain or increase the function as well as the life span.To strengthen concrete structures by using adhesively bonded fibres or fibre reinforced polymers (FRP) has been shown to be an excellent way of improving the load bearing capacity. The most common adhesive used for this type of strengthening is epoxies. Unfortunately, there are some drawbacks with the use of epoxy adhesives such as diffusion tightness, poor thermal compatibility with concrete and requirements for a safe working environment which might lead to allergic reactions if proper protective clothing is not used. A further limiting factor is the requirement on the surrounding temperature at application. A commonly recommended minimum temperature at the time for application is 10°C, which makes the preparations regarding application during colder seasons much more complicated. However, some of these drawbacks could be reduced by substituting the epoxy adhesive for a mineral-based bonding agent with similar material properties as concrete.The strengthening system and also the topic of this thesis is termed "mineral-based composites" (MBC). The MBC consists in this context of grids of carbon FRP with high tensile strength that are bonded to an existing concrete surface by the use of a cement based bonding agent.The scientific approach in this thesis includes analytical methods to describe load bearing capacity for the strengthened concrete structure in both flexure and shear. The analytical approaches are then verified against experimental results. Above the theoretical and experimental performance of the MBC system a review of state of the art research has been made in order to collate and map existing mineral-based strengthening systems other than the MBC system.To develop and verify the theoretical models and to compare the performance of the MBC system to other possible designs of mineral-based strengthening systems, six papers are appended in the thesis. - The first paper describes the performance of the MBC system when used in flexural strengthening. The experimental program in this paper consists of a concrete slab strengthened with both the MBC system and epoxy based system. In addition, a parametric study was made on small scale beam specimens to evaluate the performance of using different cement-based bonding agents.- The second paper describes the performance of the MBC system when used as shear strengthening. This study consists of experimental results of 23 reinforced concrete beams with different concrete qualities, internal shear reinforcement ratios together with different variations of the CFRP grid design and mineralbased bonding agents. In addition, a comparison is also made to traditional epoxy-based strengthening. This paper also has an analytical approach to estimate the shear resistance.- The third paper describes existing mineral-based strengthening systems and how these perform in comparison to the proposed MBC strengthening system in shear and flexure.- The fourth paper maps different possibilities to design and combine various materials in order to obtain a mineral-based strengthening system. This paper also consists of experimental research on the tensile behaviour of the MBC system when using high performance fibre reinforced cementitious bonding agents (engineered cementitious composites - ECC). In addition, these results and discussions are also coupled to the observations made in flexural and shear strengthening.- The fifth paper gives suggestions on how to estimate the shear bearing capacity of MBC strengthened concrete beams. The suggested shear design approaches are mainly based on traditional shear design models based on truss analogy, but one design presented is based on the compression field theory.- The sixth and last paper describes the strain development in a shear strengthened concrete beam both with and without the MBC system. All of the results from the investigations made in this thesis indicate that the MBC system contributes to increasing the load bearing capacity for strengthened concrete structures considerably. It is also shown that the MBC system can give competitive strengthening effects compared to existing epoxy bonded strengthening systems. From the experimental investigations on the shear strengthened beams it is shown that the strains in the shear span are lowered compared to a non strengthened specimen. This reduction of strains is also shown in the transition zone between the development of macro cracks from micro cracks. The suggested analytical approach in order to estimate the load bearing capacity of strengthened concrete structures in both flexure and shear indicates that realistic estimations can be made. The flexural design is straightforward while the shear design is more intricate. It is however concluded that a simple and safe design could be made based on the "additional" approach using a 45° truss. / En betydande del av samhällets tillgångar är investerade i vår existerande infrastruktur som t ex järnvägsbroar, vägbroar, tunnlar, dammar,, fastigheter etc. En majoritet av dessa konstruktioner är byggda av armerad betong. Samtliga av dessa betongkonstruktioner har både en förväntad funktion och en förväntad livslängd. Men både funktionen och livslängden kan komma att ändras på grund av yttre påverkande faktorer som till exempel nedbrytning och förändrade belastningsförhållanden. Ytterligare kan vara tidiga misstag i projekteringsfasen eller under själva uppförandet. Genom reparation och/eller förstärkning kan både funktion och livslängd hos dessa konstruktioner ofta återställas eller till och med uppgraderas. Förstärkning av betongkonstruktioner genom att limma fast kolfiberväv eller kolfiberkompositer har visat sig vara en bra och tillförlitlig metod för att öka bärförmågan hos befintliga konstruktioner. Det lim som till största delen används vid denna typ av förstärkning är epoxilim. Dessvärre har epoxilim vissa nackdelar, så som diffusionstäthet, dålig termisk kompabilitet med betong och krav på skyddad arbetsmiljö. Ytterligare en begränsande faktor är kravet på omgivande temperatur vid limning. Vissa av dessa nackdelar kan reduceras genom att byta ut epoxilimmet mot en mineralbaserad vidhäftningsprodukt med egenskaper liknande betongens.Förstärkningssystemet som omfattas av denna avhandling har benämningen "mineralbaserade kompositer" (MBC) och omfattar kolfibernät med hög draghållfasthet som fästs på befintlig betongkonstruktion med ett cementbaserat bruk.Det vetenskapliga förfarandet i denna avhandling omfattar analytiska metoder för att beskriva bärförmågan för den förstärkta betongkonstruktionen i både böjning och tvärkraft. De analytiska metoderna är sedan verifierade mot laboratorieförsök. Utöver de teoretiska och experimentella resultaten för MBC systemet så ingår även en aktuell granskning och kartläggning av existerande mineralbaserade förstärkningssystem och därmed möjliga materialkombinationer och utformningar, dvs. andra än MBC systemet.Avhandlingen består av en litteraturstudie och sex bifogade artiklar.Den första artikeln beskriver hur MBC system uppför sig vid förstärkning i böjning. I denna artikel ingår provning av en större betongplatta som förstärkts med MBC systemet och epoxibaserade system samt en parametersstudie på småskaliga provkroppar med MBC systemet och olika cementbaserade bruk.Den andra artikeln beskriver hur förstärkningssystemet presterar vid förstärkning i tvärkraft. Denna studie omfattar experimentella resultat på 23 balkar med olika betongkvalitéer, armeringsmängd samt olika variationer av MBC systemet och jämförelse mot traditionell epoxibaserad förstärkning. Dessutom innehåller denna artikel en analytisk uppskattning av tvärkraftskapaciteten.Den tredje artikeln beskriver olika existerande förstärkningssystem och hur dessa presterar i jämförelse med MBC systemet i böjning och tvärkraft.Den fjärde artikeln kartlägger olika möjligheter till att kombinera material i mineralbaserade förstärkningssystem för att optimera dessa system. Dessutom ingår även experimentella försök med ett högpresterande fiberförstärkt cementbruk (ECC). Denna artikel omfattar även resultat och diskussion om MBC systemets beteende i enaxligt drag, brottenergiupptagande förmåga samt hur dessa observationer kopplas till iakttagelser i böj- och tvärkraftsförstärkning.Den femte artikeln behandlar en rekommendation till dimensionering för tvärkraft av MBC systeme baserat på traditionella dimensioneringsmetoder med fackverksteori samt en ny tillämpning baserat på tryckfältsteori.Det sjätte bidraget beskriver hur töjningsutvecklingen sker i tvärkraft för betongbalkar med och utan MBC systemet.Resultaten från dessa undersökningar indikerar på att MBC systemet bidrar till att öka bärförmågan hos förstärkta betongelement och att denna ökning kan i vissa avseenden jämföras mot epoxibaserad förstärkning. Det är även visat att MBC systemet, i tvärkraftsförstärkning, bidrar till att minska töjningar i det armerade betongtvärsnittet i övergångszonen mellan tillväxten av mikrosprickor till makro sprickor samt att töjningarna reduceras även under öppningen av makrosprickor. Analytiska metoder för att uppskatta bärförmåga för förstärkning i böjning och tvärkraft är redovisade och dessa indikerar på att realistiska uppskattningar är möjliga. Dimensionering av bärförmågan i böjning är relativt enkel medan dimensionering i tvärkraft är lite mer komplicerad. En av slutsatserna gällande tvärkraftsdimensioneringen är att det är möjligt på ett enkelt sätt använda befintliga dimensionerings anvisningar grundade i "additions" principen för att uppnå en säker uppskattning av bärförmågan i tvärkraft. / Godkänd; 2009; 20090313 (thojoh); DISPUTATION Ämnesområde: Konstruktionsteknik Opponent: Professor Thanasis C Triantafillou, University of Patras, Grekland Ordförande: Professor Björn Täljsten, Technical University of Denmark och Luleå tekniska universitet Tid: Fredag den 24 april 2009, kl 10.00 Plats: F 1031, Luleå tekniska universitet

It is well known for contractors that due to volume change during the hydration phase in concrete structures, large stresses can arise if the structures are restrained, stresses that may cause extensive cracking. Crack risk estimation of early age concrete structures can be based on five steps. Firstly, the type of structure, the material proportions and possible measures to avoid cracking have to be chosen. Secondly, the temperature development has to be determined, and thirdly the restraint situation. Fourthly, structural calculation of the stress or strain ratios follows, which in the fifth step are compared to stated partial coefficients that should not be exceeded. The restraint situation is one of the crucial factors in the crack risk analyses. A semi-analytical method has been derived for the determination of the restraint variation in early age concrete structures and especially for the case wall on slab. The method is derived using compensated line theory. The model depends on the geometry of the structure, the boundary restraint situation, and the location of the young parts on the old parts. The model is supplemented with the effects of high walls and the effects of short structures and/or possible slip failure in the ends of the joint between the young and the old concrete. The model is by regression technique compared to almost 3000 3D elastic FEM calculations of the restraint variation in walls on slabs with different dimensions and base restraint situations. The effective width of the slab is introduced as the only adjustment parameter to get the model to correspond with the FEM calculations. Partial coefficients for thermal cracking problems of young concrete have been calculated and compared with the values stated in the Swedish building code for bridges. The code values are only based on experiences and logical reasoning, whereas the calculated values form a more theoretical base for their determi-nation. The coefficients are calculated with a probabilistic method. Various possible variations of the used variables have been studied showing the wide range of possible results depending on the input. However, with use of material properties and reasonable assumptions related to thermal cracking problems, fairly good agreement has been found between the stated values in the Swedish code and the values obtained through the probabilistic method. / Godkänd; 2003; 20061106 (haneit)

Contracts for the operation and maintenance of roads and streets are today characterized by short-term perspectives and a low rate of development. One reason for this is that the client placing an order, within the framework of traditional contract procedures, specifies in detail what shall be done and sometimes even orders a certain type of machinery and equipment. The contractors are not made aware of the longterm quality ambitions of the client with respect to traffic safety and ease of flow. A performance contract means that the client, instead of presenting technical solutions, makes measurable functional demands with regard to the finished product. The demand is for example made that the road surface shall have a certain smoothness and a certain friction The functional requirements are formulated so that they have a direct relevance for the safety and flow of traffic. The functional requirements should be divided into an absolutely lowest permissible level (acute level) and a target level. The target level shall be maintained both as an average functional level during the contract period and when the contract is completed. Functionally directed road maintenance should include measures to reduce traffic disturbances to a minimum. It should also be required of the contractor that he reports planned measures to the relevant road-user information centres. Performance contracts radically change the roles of both the client and the contractor. The client's efforts are concentrated on controlling the quality of the final product from a user point of view, while the contractor takes over many of the traditional roles of the client such as planning, projecting, choice of technical solutions, choice of material and duty activities. Direct contact with road-users and residents will also be included in the tasks of the contractor. The advantages of a performance contract are the functional expectations of the users become the guiding star for the contractor it stimulates the development of creative solutions by the contractor the responsibility boundary between client and contractor becomes "sharp" Trials with performance contracts for operation and maintenance have been carried out in both Sweden and the USA. / Godkänd; 1993; 20070426 (ysko)

Probabilistic methods are presented for the assessment of bridges. Load carrying capacity calculations and evaluations of strengthening methods are carried out for three road bridges in northern Sweden: 1) The E4-bridge over Pite River - A four span steel beam bridge with a concrete deck built in 1969. The capacity of the edge beams are evaluated with use of calculations and monitoring results. Strengthening measures are discussed and recommended. 2) Bridge over Kuivajärvi - A one span concrete slab-frame bridge built in 1954. The supports have moved transversally towards each other causing cracking in the deck. Strains and deflections are monitored and the capacity is evaluated. 3) Bridge over Åhedån - A one span concrete beam-frame bridge built in 1934. The bridge was to be widened and the load carrying capacity of an increased cross section is studied. Monitoring and testing of material properties have given valuable information of the real behaviour of the studied bridges. Bayesian updating of original data has been shown to be very useful. Further research work is needed regarding the uncertainty coefficients for the studied models and parameters in order to fully take advantage of the possibilities to assess existing bridges with probabilistic methods. / Godkänd; 2008; 20080512 (ysko)

This thesis aims to answer questions regarding material and fatigue properties of bridges built between the end of the 19th century to 1940's. Regarding material properties the study involves the creation of a data base consisting of material properties of bridges. The establishment of a data base was done by retrieval of test certificates from material investigations conducted on existing bridges. The bridges in question were road and railway bridges produced before 1940's. The aim of the investigation was to determine the material properties of bridges in the specified interval and compare these with properties in evaluation codes. From the evaluation of the data base it became apparent that the yield strength of the existing bridges was higher than specified in the evaluations codes of Sweden and Denmark. Also a big divergence regarding the toughness properties were established for the investigated bridges. Regarding fatigue endurance, a literature survey of fatigue tests performed on riveted structures were conducted. The survey concerned both full scale structures retrieved from bridges taken out of service and small scale tests. The objective was to investigate the fatigue resistance of riveted structures. Factors as hole preparation, corrosion, clamping force and influence from materials properties on the fatigue performance was also inquired. In the evaluation of the fatigue tests it was concluded that fatigue endurance of riveted assembled girders was best described by the detail category C=63. / Godkänd; 2006; 20070109 (haneit)

Asphalt compaction is one of the most important phases of road construction, being the decisive phase when the structure of the asphalt pavement layer is formed. In spite of its importance, the knowledge about this construction phase is still based on empirical and technological background and therefore surprisingly limited. This lack of knowledge is also due to the fact that the existing laboratory scale compaction devices for mix design are not fully capable of simulating the field compaction. The simulation of asphalt compaction in the laboratory is normally focused on the vertical rearrangements of asphalt particles whereas the flow behavior of these particles in other directions is mostly neglected. However, existing literature suggests that the neglected flow is one of the most important factors for the quality of the road construction, particularly in special cases such as asphalt joints. Therefore, building up a better understanding of the flow behavior of asphalt mixtures subjected to compaction loads is needed for improving the quality of the pavements. In this study, a new test setup, the so called Compaction Flow Test (CFT), was developed to simulate the flow behavior of asphalt mixtures at early stages of compaction. In the first step, feasibility tests were performed, substituting asphalt mixtures by model materials with simple geometries and less complex properties. X-ray Computed Tomography (CT) was utilized for capturing 2D radiography images of the flow patterns in the model material during the test. Results of the CFT showed the capability of the new test setup to clearly distinguish between model mixtures with different characteristics. Hence, in the next step, the CFT was applied to real asphalt mixtures and the obtained results were found to support the findings of the feasibility tests with the model materials. The results from the feasibility tests encouraged examining the possible use of an ultrasonic sensor as alternative to the complex and costly X-ray imaging for flow measurements during the CFT. Hence, the CFT was used along with a distance measuring ultrasonic sensor for testing asphalt mixtures with different characteristics. The test results confirmed that an ultrasonic sensor could be effective for capturing the differences of the flow behavior of asphalt mixtures tested by the CFT.  In addition, a parametric study with the X-ray setup was carried out to examine the capability of the CFT in reflecting the possible changes of the flow behavior in asphalt mixtures due to the change of construction parameters such as lift thickness, bottom roughness and compaction modes. The results obtained also confirmed the capability of the CFT in showing the possible differences in the flow behavior of the mixtures under the chosen conditions. The encouraging results suggested that the CFT may have potential to become a simple but effective tool for assessing compactability of the mixtures on-site, right after production in an asphalt plant or before placing the mixture on the road. Hence, discrete element method (DEM) was utilized to understand both the influence of selected boundaries of the CFT and the effect of its design on the results. As one specific example of application, an investigation was carried out using the CFT to find the most suitable tracking method for flow measurements in the field. Based on the literature review and feasibility tests, a tracking method with the highest potential for conducting flow measurements during field compaction was introduced. X-ray radiography confirmed the validity of the results obtained with the suggested method. The overall results obtained from this study suggest that the recommended CFT along with the suggested field tracking method may be helpful in building up a comprehensive basis of knowledge on the flow and compaction behavior of asphalt mixtures thus helping to close the gap between the field and laboratory. / <p>QC 20171214</p>

All over the world, megaprojects have become entrenched and firmly positioned in the development of cities and have become instrumental and critical in their position and functioning. The need for sites to be developed encompassing mixed-use requirements, was soon to make its impact in developing countries. Investors and developers were considered the experts in urban development through these projects. The now notable effects from the surge in megaprojects in developing countries in the wake of decaying infrastructure and migration to cities and urban spaces, warrants analysing, studying and investigating existing, especially more current mixed-use megaprojects. Megaprojects built with the motivation of the criteria for "enhancing and developing" the urban space for its citizens that encourages economic, social and environmental growth would be alluring to any governing administration. This is because they can be considered as developments that will address the spatial patterns of apartheid, creating inclusive and integrated urban spaces. Considering these impacts, Century City, as a commercial mixed-use mega project development is a relevant case for study. My dissertation analyses and interrogates the factors that influenced and substantiated the development of Century City from its inception to the present. I will examine how the development coexists, and complements or not, Cape Town and its people and how it may or may not support the policy approaches toward a successful African city. I question whether megaproject developments in our cities, is development that transmits to the entire city and its community.