1 MAT-03 Invloed van hulpstoffen in beton op het korte termijn en lange termijngedrag Influence of additives in concrete on its short term and long term behaviour Anne Beeldens; Lucie Vandewalle Number of students: 1 or 2 Language of thesis: Dutch or English BWK and/or IRA Description of the problem: The properties of concrete have altered to a great extent the last decennia due to the addition of new additives. The durability and especially the resistance to freeze-thaw cycles have increased significantly due to the reduction of the water/cement ratio by the addition of (super-)plasticizers and the use of air entraining agent. However, more and more the compatibility of these additives is questioned. Delamination and scaling appear more and more frequent in industrial floors. This is probably linked to excessive air content due to the interaction between the air entrainer and the superplasticizer. It is also seen that in some cases the mixture is not stable, i.e. a small variation in air entrainer or in superplasticizer leads to a large variation in air content and workability. The goals of the thesis are to give an overview of different types of additives for concrete used in road construction. Consequently the influence of these additives on the workability and the air content of the concrete have to be determined. By this the compatibility of the different types of additives is important. Therefore the main goal of this thesis is the development of a test method in order to determine the stability and the compatibility of different types of additives. After a bibliographic exercise a choice of products will be made to be tested. The tests to be performed are in a first phase focusing on the properties of the fresh concrete mix, i.e. workability and air content. However, as the composition of the concrete and especially the water content (depending on the amount of super plasticizer) and air content influence the durability and mechanical behaviour of the concrete some additional tests on the hardened concrete will be made. In order to determine the stability and the mutual influence, an adaptation (i.e. an extension in time or an alteration in composition) of the classic test methods have to be provided.
2 MAT- 04 Vorstweerstand van wegenbeton op jonge leeftijd Scaling resistance of concrete at young age Anne Beeldens; Lucie Vandewalle Assistant(s): Number of students: 1 or 2 Language of thesis: Dutch or English Project link: BWK and/or IRA Description of the problem: The durability of concrete is an important parameter to obtain a sustainable concrete pavement. During the life time of 30 to 50 years, the concrete has to resist freezing and thawing cycles in the presence of de-icing salts. This resistance is largely depending on the composition of the concrete as well as on the execution of the concrete pavement. An optimal composition (high cement content, low w/c-ratio, limited amount of sand, sufficient air content, ) will lead to a durable concrete. However this resistance against scaling is only guaranteed if the concrete is not submitted to de-icing salts at young age. A time gap of 6 weeks is now prescribed during which no de-icing salts may be applied on the concrete. This gives concerns for the contractor as often the pavement is placed adjacent to an existing pavement where traffic is allowed. This means that de-icing salts will be applied if frost is present and consequently the melting water with a high concentration on de-icing salts may flow over the newly lead concrete and cause scaling. Goal of the thesis: The goals of the thesis are the determination of the minimum delay during which no de-icing salts may be applied in order to avoid scaling. This will be done for concrete applied on highways, on secondary roads as well as on local roads. Consequently, prevention measures will be developed such as excessive curing, increased air content,.the influence of these measures on the scaling resistance at young age and on the final durability will be determined. After a bibliographic exercise, the thesis will concentrate on two test series. In a first series different types of concrete (in relation to the category of the road) will be submitted to a freezing-and thawing test at different ages (from one week to 6 weeks of curing). In a second series of tests, different prevention measures will be applied on one type of concrete in order to determine the influence of this measure on the obligatory delay period without de-icing salts determined in the first series.
3 MAT-05 Studie van optische vezels voor slimme versterking van een metselwerkboog. Fiber optic sensors (FOS) for self-sensing strengthening of masonry arches dr. ir.-arch. Els Verstrynge, prof. Koen Van Balen Number of students: 1 or 2 Language of thesis: Dutch is standard, English if desired by student BWK and/or IRA The most common application of optical fibers is data transfer (ex. internet). They rely on the principle of internal reflection of a light wave within the core of the fiber to transfer signals over long distances with minimum loss and without electromagnetic interference. However, optical fibers are also applied as sensors in many applications. These fiber optic sensors detect changes of a certain parameter by relying on the influence that this parameter has on a property of the light which travels in the fiber. An external influence can for example change the light intensity, polarization state or interference. This way, a large range of parameters can be monitored by means of optical fiber sensors: pressure, temperature, strain, vibrations, acoustic emissions, Crack growth in historical structures is mostly monitored by means of simple crack meters or hand-held devices for deformation monitoring. Often, a scaffold is needed to reach difficult places, such as masonry arches and vaults. In case large structures or a large amounts of cracks needs to be monitored permanently, this can become very labor-intensive and uneconomical. Traditional strain gauges are point sensors, which means each measurement requires a separate, glued-on sensor. The advantage of fiber optic sensors is that they can be several meters long and can function as distributed sensors. The latter means that measurements can be performed at any point along the length of the fiber, while only the fiber end needs to be in a reachable position. The aim of this study is not to develop fiber optic sensors, but to study the opportunities and challenges for application of distributed fiber optic strain sensors for application in brittle construction materials such as masonry and concrete. This study includes: - literature study on the existing types of distributed fiber optic strain sensors - market study on the commercially available fiber optic strain sensors These studies will focus on the accuracy, feasibility, durability, cost and limitations of the different techniques. Figures: Optical fiber sensor (Smartape) integrated in masonry wall (left); testing on small masonry arches (right).
4 Secondly, a hands-on experimental study will be performed in which a selected sensor is applied on a small masonry arch and test results are compared with traditional strain gauges in terms of accuracy and possibilities for integration of the sensors inside the wall. Thirdly, the fiber optic sensor will be applied on a similar masonry arch. However, this second arch will be strengthened with carbon fiber reinforced polymer (CFRP) or steel wire reinforced grout (SRG) and the optical fiber sensor will be included in the strengthening material. Aim is to develop a smart, self-sensing strengthening material which both strengthens and monitors the deformations in the arch. Referentie: Yasmine Van Roosbroeck & Pieter-Jan Haest: Schadedetectie in historisch metselwerk met optische vezels, MasterThesis 2012, KU Leuven.
5 MAT-06 - ontwerpthesis Ontwerp van een geavanceerd systeem voor Smart Renovation Design of advanced systems for Smart Renovation dr. ir.-arch. Els Verstrynge, ir.-arch. Leo Van Broeck Assistant(s): ir.-arch. Kristof De Wilder assessor(s): prof. Mattias Schevenels Number of students: 1 or 2 Language of thesis: Dutch is standard, English if desired by students 1 student IRA or 2 students IRA or 1 student IRA and 1 student BWK We drive into the future using only our rear view mirror , a statement by Marshall McLuhan was applied by Erik Geens, tutor at Sint. Lucas to point at the importance of the history of architecture and building techniques as steppingstone for reinvention and progress in architecture. This thesis proposal takes another point of view, this of the side window. Taking into account that your education at KU Leuven has provided you with the necessary stepping stones, this thesis project asks you to look aside (or maybe even in front) at novel techniques emerging in other disciplines which might be of interest in building and architecture. You will be asked to select and visit two recent renovation projects (case study) and report on the integration of smart (interactive, intelligent, adaptable ) materials and techniques which were applied in these projects. Secondly, you will visit a leading company or research institute either in sensor technology (e.g. IMEC) or materials technology (e.g. Sirris-MTM) and investigate possibilities for application of their products in the renovation sector (innovation study). Thirdly, in the design part of the project, you will propose and design a new material, system or solution (based on one of the novel materials or sensor types which you have studied) specifically for renovation purposes. Examples are the adaptable material characteristics of fiber reinforced polymers and textiles, which allow novel complex shapes and advanced shape optimization. Or how could a renovation project benefit from 3D printing techniques? Another example is the integration of solar panels in external cladding systems, but you could go even further, since novel types of solar cells ( organic ) are partly transparent Figures: examples of traditional systems  Marshall McLuhan, The Medium is the Massage [sic], p.74-75, (1967), ISBN
6 MAT-07 Partikelgebaseerde modellering van zelfverdichtend staalvezelbeton nabij nauwe openingen Particle-based modelling of steel fibre reinforced self-compacting concrete near a small gap Prof. dr. ir. Lucie Vandewalle Assistant(s): Ing. Joren Andries Number of students: 1 Language of thesis: Dutch BWK or IRA Steel fibre reinforced self-compacting concrete (SFRSCC) combines the benefits of self-compacting concrete (SCC) in the fresh state and an enhanced performance of fibre reinforced concrete (FRC) in the hardened state, i.e. a higher post-cracking strength. For applications where fibres are used in combination with conventional reinforcement, the minimum gap distance is an important parameter to consider before casting an element. [1, 2] When blocking occurs, it may even prevent the proper filling of the formwork. Especially near narrow openings, the shape of coarse aggregates and fibres is of great importance as contact interactions between the particles and with the reinforcement bars will dominate the flow. A model that combines features from both Discrete Element Modelling (DEM) and Smoothed Particle Hydrodynamics (SPH) to simulate the flow of concrete is currently in development at KU Leuven and will be used for a parameter study. Results of the experiments of two previous master theses [3, 4] can be used as a benchmark. The influence of particle shape and grading of the coarse aggregates is investigated to verify how many detail about the shape of the aggregates needs to be accounted for in SCC flow simulations. Small scale (not more than a few litres of concrete) flow simulations will be used in this thesis to predict particle blocking as a function of the fresh properties of the mortar phase, aggregate/fibre shape, bar spacing, formwork geometry and flow conditions. Interested students should contact Joren Andries References  S. Grünewald, "Performance-based design of self-compacting fibre reinforced concrete," PhD-thesis, TU Delft,  H. B. Dhonde, Y. L. Mo, T. T. C. Hsu, and J. Vogel, "Fresh and Hardened Properties of Self- Consolidating Fiber-Reinforced Concrete," ACI Materials Journal, vol. 104, pp ,  N. De Ridder and M. Van Vlasselaer, "De invloed van de korreleigenschappen en -verdeling op de reologie van zelfverdichtend beton," MSc-thesis, Campus De Nayer,  L. Versmissen and W. Coomans, "Capaciteit van zelfverdichtend staalvezelbeton om door nauwe openingen te stromen," MSc-thesis, Campus De Nayer, 2014 (expected).
7 MAT-08 Invloed van voorspanning op de dwarskrachtcapaciteit van betonbalken experimenteel onderzoek en numerieke modellering Influence of prestressing on the shear capacity of concrete beams experimental investigation and numerical modeling Promotor(en): prof. dr. ir. Lucie Vandewalle Begeleider(s): ir.-arch. Kristof De Wilder Contactperso(o)n(en): Aantal studenten: 1/2 Studierichtingen: ir.-bwk/ir.-arch. Nagenoeg alle structureel betonnen balkelementen worden belast op dwarskracht. In elke sectie waar immers een variërend buigmoment aanwezig is, heerst er een dwarskracht. Buiging echter, heeft nagenoeg geen geheimen meer voor onderzoekers en ontwerpende ingenieurs. Dit geldt hoegenaamd niet voor dwarskracht. Dwarskracht is een complex fenomeen waarbij heel wat parameters een rol spelen. Door deze complexiteit zijn ingenieurs veelal aangewezen om gebruik te maken van (semi-)empirische uitdrukkingen die opgesteld zijn aan de hand van zeer veel proefresultaten uit laboratoria. De laatste decennia is er een uitzonderlijke onderzoeksinspanning geleverd om beter inzicht te krijgen in het structurele gedrag van betonnen structuren die op dwarskracht belast zijn. Door het structurele gedrag te beschrijven, koppelt men zich los van de afhankelijkheid van proefresultaten waardoor meer betrouwbare en accurate formuleringen ontstaan. Er is tot op vandaag echter geen algemeen aanvaarde basis gevonden die dit gedrag correct kan beschrijven. Dit onderzoek tracht een bijdrage te leveren tot een verbeterd inzicht in de interne krachtswerking en mechanismen van betonnen structuren die op dwarskracht belast worden. Er wordt voornamelijk geconcentreerd op voorgespannen betonnen elementen. Het onderzoek bestaat uit twee grote luiken. In een eerste fase zal experimenteel onderzoek uitgevoerd worden in het Laboratorium Reyntjens. Het proefprogramma zal in nauwe samenwerking verlopen met de firma Ergon. De studenten komen in contact met geavanceerde experimentele meettechnieken (optische meettechnieken). De verkregen experimentele resultaten zullen vervolgens geanalyseerd worden en vergeleken worden met eerder bekomen experimentele gegevens. In een tweede fase zal, gebaseerd op een uitgebreide literatuurstudie, een doorgedreven analytische en numerieke studie uitgevoerd worden teneinde het opgetekende structureel gedrag te kunnen verklaren. Een vergelijking met bestaande analytische modellen kan gemaakt worden. Geïnteresseerde studenten dienen contact op te nemen met Kristof De Wilder.
8 MAT-11 Diafragma werking van de dakhuid bij staalconstructies Diaphragm action of steel sheeting in steel structures Promotor(en): prof. dr. ir. Luc Schueremans Begeleider(s): Luc Schueremans (KULeuven/Frisomat NV), Tom Jeurissen Contactperso(o)n(en): Aantal studenten: 2 (1) Studierichtingen: bwk, ir-arch Schijfwerking in staalgebouwen levert een belangrijke bijdrage in de langse (en dwarse) krachtswerking van een gebouw. Daarop kan ook gerekend worden bij het ontwerp van het gebouw. Omdat de impact van de krachtswerking afhangt van vele factoren, wordt deze gebaseerd op een numerieke methode gevoed door experimentele resultaten ( Diaphragm action) uit [EN :2006]. Doelstelling van dit eindwerk is: In een experimentele opstelling de schijfwerking (gedrag en grootte ervan) in kaart te brengen. Dit zal uitgevoerd worden in functie van een aantal parameters, waaronder het type van bekleding, het type en het aantal van verbindingsmiddelen, enz.; Numeriek de vastgestelde schijfwerking te begroten zodat deze mee kan genomen worden in het ontwerp; De meerwaarde van de schijfwerking in gehelde daken en wanden aan de hand van een concreet voorbeeld in rekening te brengen om de impact ervan te quantificeren. Figuur: basisopstelling voor een enkelvoudig paneel [EN , Figuur ] Het eindwerk wordt uitgevoerd in samenwerking met Frisomat NV. De proefstukken worden opgebouwd en uitgevoerd in het FIC (Frisomat Innovation Centre). Referentie: EN : Ontwerp en berekening van staalconstructies - Deel 1-3: Algemene regels - Aanvullende regels voor koudgevormde dunwandige profielen en platen (+ AC:2009), 2007.
9 MAT-12 Ontwerpen en berekenen van staalconstructies in de 19 de eeuw Design and calculation of steel structures in the 19 th century Promotor(en): dr. ir.-arch. Els Verstrynge, prof. dr. ir. Luc Schueremans, prof. Barbara Rossi (DeNayer) Begeleider(s): Luc Schueremans (KU Leuven) Contactperso(o)n(en): Aantal studenten: 2 (1) Studierichtingen: bwk, ir-arch Dit eindwerkonderwerp vloeit voort uit een ver- en bewondering. Vandaag beschikken we over een heel gamma aan krachtige rekenmethodieken om de veiligheid van onze staalconstructies te waarborgen. Deze houden rekening met allerlei instabiliteitsfenomenen waarvoor én jaren aan onderzoek zijn voorafgegaan én waar veel experimenteel en numeriek onderzoek aan de basis van liggen. Echter, in de beginjaren van de 19 de eeuw bij de opgang van de staalnijverheid in volle industriële revolutie, werden bijzonder ingenieuze staalconstructies opgetrokken, waarvan de omvang vaak groots was en waarbij de gebruikte slankheid van elementen verwondering opwekt. Voorbeelden daarvan zijn talrijk en een aantal daarvan zijn nog steeds getuige van de ingenieurskunde (of: ingenieurskunst?) van die tijd: stationskathedraal te Antwerpen (C. Van Gogaert, )), Kroonserre te Meise (1854, A. Balat), St.- Pancras te Londen (William Henry Barlow, ), Abattoirs te Anderlecht (1890, Emile Tirou), Vlaams Tram- en Autobusmuseum te Berchem (52m vakwerkoverspanning), Crystal Palace, London (Joseph Paxton, 1851), Galérie des Machines, Paris (Contamin and Dutert, 1889 met een vrije overspanning van 110.6m), Royal Museum of the Armed Forces and of Military History, Brussels (fr. Heyninx and Gédéon Bordiau, 1888) Centrale Werkplaats NMBS, Hal 9 te Kessel-Lo, Monte Video te Antwerpen, en ga zo maar door. Heel wat van deze staalconstructies zijn opgebouwd uit onderdelen met beperkte omvang en samengebracht tot een (ruimtelijke) vakwerkstructuur, al dan niet (gedeeltelijk) in boogvorm. Doel van dit eindwerk is te onderzoeken welke rekenmethodieken gebruikt werden bij het ontwerp van staalconstructies in de 19 de eeuw en in welke mate het ontwerp stoelde op ervaringsgegevens, schaalvergroting van eerdere ontwerpen die hun deugdelijkheid bewezen, materiaalgegevens, constructiemethode, enz. Figuur: Links Abattoirs te Anderlecht Rechts Galérie des Machines, Paris Referenties: - Historical structural steelwork handbook, The British Constructional Steelwork Association Ltd., L. Lauriks, Contribution of the glass cladding to the overall structural behaviour of 19th-century iron and glass roofs, PhD Thesis, Leen Lauriks, VUB, October S. Van Mulders, Restoration study Winter Garden of Royal Greenhouses, Brussels, Msc Thesis, VUB, M. Bussell, Appraisal of existing iron and steel structures, 1997, ISBN , Publisher SCI.
10 MAT-13 Katalyserende werking van organische additieven op carbonatatie van kalk mortels Catalytic effect of organic additives on lime mortar carbonation prof. dr. Özlem Cizer, prof. dr. Koen Van Balen Assistant(s): to be determined prof. dr. Özlem Cizer, Number of students: 1 or 2 Language of thesis: Dutch is standard, English if desired by supervisor(s) or assistant(s) BWK and/or IRA Carbonation reaction of lime in mortars is the reaction of carbon dioxide (CO 2 ) in air with lime (Ca(OH) 2 ) forming calcium carbonate (CaCO 3 ). This hardening reaction improves the mechanical properties of lime mortar which is crucial for structural integrity and durability of the masonry. This reaction requires conditions where pore structure is sufficiently open to allow carbon dioxide diffusion and water is present in the pores to allow dissolution of carbon dioxide and calcium hydroxide. Therefore, the carbonation reaction of lime mortars proceeds gradually and may continue up to 1 year or more to reach a complete conversion yield. For such reasons, slow hardening reaction of lime mortar carbonation is recognized as the main drawback limiting their use in restoration works. To overcome this and to promote their use in repair mortars, novel tools are needed to speed up the natural carbonation process of lime mortars and to improve the hardened mortar properties in a shorter period of time. A promising alternative way to improve lime mortar carbonation is the use of certain organic compounds which can catalyze the rate-controlling step of absorption/dissolution of carbon dioxide in water. In this master thesis, it will be aimed at mastering the carbonation of lime mortars using calcium lignosulfonate and a biological enzyme of carbonic anhydrase (CA) which is novel in this field. The catalytic effect of CA enzyme on the kinetics of carbon dioxide hydration has proven to be successful in certain industrial applications, and has recently proven to be effective on lime carbonation by our research group for the first time. Ultimately, this work will explore how the two additives will improve the carbonation reaction rate, its yield and eventually the hardened properties of the lime mortar. The studied parameters will be the effective role of the selected two additives on: rate of carbonation reaction (carbon dioxide uptake and carbonation yield) hardened mortar properties (drying shrinkage, strength development and porosity) This thesis study requires a combination of theoretical study and laboratory work that will involve a series of analytical techniques on binders and testing methods on mortars. The results will contribute to the application of lime mortars in the restoration works of historic masonry structures, and to the field of sustainable construction materials that can sequestrate carbon dioxide. References: 1. Elert, K., Rodriguez-Navarro, C., Pardo, E.S., Hansen, E., Cazalla, O Lime Mortars for the Conservation of Historic Buildings. Stud. Conserv., 47, Van Balen K. and Van Gemert D Modeling Lime Mortar Carbonation. Materials and Structures 27, Cizer, Ö., Van Balen, K., Elsen, J., Van Gemert, D. (2012). Real-time investigation of reaction rate and mineral phase modifications of lime carbonation. Construction & Building Materials, 35, Cizer, Ö., Ruiz-Agudo, E., Van Balen, K., Rodriguez-Navarro, C. (2013). The kinetic effect of carbonic anhydrase on CaCO 3 phase transformations during carbonation of Ca(OH) 2 solutions, ACEME 2013 (pp ).
11 MAT-14 Ontwikkeling van alternatieve bindmiddelen uit staalslakken en kleien voor duurzame bouwmaterialen Development of alternative binders from steel slags and clays for sustainable construction materials prof. dr. Özlem Cizer, prof. dr. Koen Van Balen Assistant(s): ir. Muhammad Salman prof. dr. Özlem Cizer, Number of students: 1 or 2 Language of thesis: Dutch is standard, English if desired by supervisor(s) or assistant(s) Project link: BWK and/or IRA Portland cement has long been utilised as a binder in providing rapid strength in cement-based and concrete applications. However, its production has now become a significant industrial activity in terms of its volumes, raw materials consumption, energy consumption and greenhouse gas emissions including at least 5-7% of the total CO 2 emissions. To reduce this environmental impact, by-products from other industrial activities such as fly ash and blast furnace slag are used as supplementary cementitious materials in blended cement and more recently as a feedstock for alkali-activated/geopolymer binders creating a novel sustainable opportunity for a variety of by-products and residual wastes such as metallurgical slags and industrial sludge. Therefore, alkali-activated binders from waste residues are seen as a potential alternative to Portland cement, and as an opportunity to convert them into beneficial construction materials within sustainable development. Fig. 2. Perforated brick block produced from steel slag activated with CO 2 via carbonation. Fig.1. Clay brick (left) and its counterpart produced from alkali activated steel slag. Within this context, utilization of industrial residual wastes as sustainable binders alternative to Portland cement has been being investigated at Civil Engineering Department within SMaRT-Pro² (1) and SIM 2(2) research consortia. The ongoing PhD research 3 performed within SMaRT-Pro² has demonstrated the fact M. Salman, Sustainable Materialization of Residues from Thermal Processes into Construction Materials, ongoing PhD research, KU Leuven.
12 that stainless steel slags, which have CaO and SiO 2 like cement but are inert in water unlike cement, can generate binding properties when mixed with Na- and K-based alkali solutions as well as with CO 2, and can be ultimately used as a binder in building blocks (Fig. 1&2). Based on this research, this master thesis will further investigate the development of sustainable binders from steel slags and clays when combined with alkalis and CO 2. Clays from deposits and waste residues are intended to strengthen the composition towards binder formation. Progress and degree of hydration, degree of carbonation, and their influence on strength development and porosity will be investigated with mortars. Simultaneously the performances and durability of the mortars will be tested. This thesis study requires a combination of theoretical study and laboratory work that will involve a series of analyses on binders and testing methods on mortars. This thesis work will contribute to the field of sustainable construction materials and sustainable development where reuse and recycling of waste is the key. References: 1. Salman, M., Cizer, Ö., Pontikes, Y., Vandewalle, L., Blanpain, B., Van Balen, K. (2013). Carbonation potential of continuous casting stainless steel slag, 4th International Conference on Accelerated Carbonation for Environmental and Materials Engineering April 2013 Leuven, Belgium. 2. Salman, M., Cizer, Ö., Pontikes, Y., Snellings, R., Blanpain, B., Vandewalle, L., Van Balen, K. (2012). Recycling of continuous casting stainless steel slag into construction material. In : Proceedings of 4th International Conference on Engineering for Waste and Biomass Valorisation, September 2012 (pp ). 3. Salman, M., Cizer, Ö., Pontikes, Y., Snellings, R., Blanpain, B., Vandewalle, L., Van Balen, K. (2012). AOD slag as construction material: investigation of binding potential by thermo-alkali activation. In: Proceedings of 32nd Cement and Concrete Science Conference, Belfast, UK, September 2012 (pp ).
13 MAT-15 Effect van wateroplosbare polymeren op microstructuur en performantie van cementgebonden mortels Influence of water soluble polymers on microstructure and performance of cement based mortars prof. dr. Özlem Cizer Assistant(s): dr. ir. Elke Knapen (UHasselt), prof. dr. Dionys Van Gemert prof. dr. Özlem Cizer, dr. ir. Elke Knapen, Number of students: 2 Language of thesis: Dutch (English if students prefer) BWK or IRA; Master Ind. Engineering Water soluble polymers (mostly cellulose derivatives like methyl cellulose MC and hydroxyethyl cellulose HEC, or other polymers like polyvinyl alcohol PVA) are added to the mortar mix as powders or as aqueous solution. The polymer modified mortar systems show better water retention, improved workability and enhanced adhesion to porous substrates. However, durability of adhesion is not always guaranteed, Fig. 1 and 2. Fig. 1. Detached tiles at front wall of warm lagoon Fig. 2. Detached tiles at parapet wall The thesis project aims to study the influence of water soluble polymers on the microstructural build up inside the modified cement mortar, with emphasis on adhesive mortars for ceramic tiles exposed to severe moisture conditions, e.g. swimming pools, sanitary installations, food industry, etc. Microstructural analysis will be based on previous studies , but will also use the most advanced analytical tools available since then: EPMA (electron probe micro analysis) and nano-sem (scanning electron microscope). The polymers most probably change the morphology and size of the crystals during hardening, as well as their interactions. Comparative investigation will be made to discover such phenomena. Simultaneously the performances and durability of the modified mortars concerning adhesion under moist conditions will be tested. These tests will also envisage application circumstances, especially the open time between spreading of the mortar and posing of the tiles, and the way of application of the tiles (posing pressure, posing movements).  Depending on the background of the candidates, the focus of the research program will be adapted. References: 1. Knapen, E., Van Gemert D., Cement hydration and microstructure formation in the presence of watersoluble polymers. Cement and Concrete Research Vol 39, Issue 1, January 2009, pp (Most cited cement and concrete research article, 2. Van Gemert D. Factors influencing durability of bond of ceramic tiles in swimming pools Proceedings 7 th ASPIC Asian Symposium on Polymers in Concrete, Istanbul 3-5 October 2012, p Eds M.H. Özkul, H.N. Atahan, Ü.A. Doğan, B.Y. Pekmezci and Ö. Şengül, ISBN
14 MAT-16 Duurzaam gebruik van AMORAS filterkoeken als hydraulisch bindmiddel in mortels Sustainable utilization of AMORAS filter cakes as a hydraulic binder in mortars prof. dr. Özlem Cizer, prof. dr. Koen Van Balen, prof. dr. Lucie Vandewalle Assistant(s): ir. Muhammad Salman prof. dr. Özlem Cizer, Number of students: 1 or 2 Language of thesis: Dutch is standard, English if desired by supervisor(s) or assistant(s) Project link: BWK and/or IRA The AMORAS (Antwerp Mechanical Dewatering, Recycling and Application of Sludge) plant established by Flemish authorities and the Antwerp Port Authority investigates a sustainable and long-term solution for the treatment and storage of the maintenance dredging material taken from the Port of Antwerp. In this treatment plant the sand in the maintenance dredging material is separated via hydrocyclones and recovered. The remaining fine silt fraction is mechanically dewatered with membrane chamber filter presses (Fig. 1). These pressed filter cakes are stored under controlled conditions at the storage site in the port area (Fig. 2). Annually about 500,000 tonnes of pressed filter cakes are disposed at the storage site or stored in extra depths, so-called underwater cells - from the bottom of the docks. However, the present storage capacity is almost completely used up and owing to the limited scope for extension in the port area a more sustainable solution needs to be found. Fig.2. Filter cakes stored at the AMORAS site. Fig.1. Pressed dredged material as filter cake after dewatering at AMORAS plant. AMORAS-SCM project has been recently launched within the collaboration of Antwerp Port Authority, VITO and KU Leuven to explore sustainable routes for the reuse of these filter cakes, representing the fine silt fraction, as a novel binder or supplementary cementitious material (SCM) in cement and concrete applications. This thesis work to be performed within the frame of this project will investigate different process parameters of calcination (temperature and duration) to enhance phase compositions that will generate hydraulic reactivity of the silt material to be used as a binding material. The binding potential of the calcined materials will be investigated through hydraulic/pozzolanic activity and alkali activation on pastes and mortar samples. Hydration reactions, reaction products, porosity and mechanical strength
15 development will be studied at varying compositions (with cement and alkalis) in accordance to the adopted protocols and norms in cement field. This thesis study requires a combination of theoretical study and laboratory work that will involve a series of analyses on binders and testing methods on mortars. This thesis work will contribute to the field of sustainable construction materials and sustainable development where reuse and recycling of waste is the key. References: 1. Shi, C, Krivenko, P. V. and Roy D. Alkali Activated Cements and Concrete, Taylor and Francis Group, Salman, M., Cizer, Ö., Pontikes, Y., Snellings, B., Vandewalle, L., R., Blanpain, Van Balen, K. (2013). Investigation of the binding potential of continuous casting stainless steel slag by alkali-activation. Advances in Cement Research, under review.
16 MAT-19 Kruipgedrag van gescheurd kunststofvezelversterkt beton onderworpen aan trek Creep of cracked synthetic fibre reinforced concrete in tension prof. dr. ir. Lucie Vandewalle, dr. ir.-arch. Els Verstrynge Assistant(s): ir. Rutger Vrijdaghs Number of students: 1 Language of thesis: Dutch or English if desired by student BWK or IRA Fibre reinforced concrete (FRC) is a composite concrete in which the traditional steel reinforcement is replaced, either entirely or partially, with fibres. These fibres are randomly distributed throughout the volume and can be made from different materials. The fibres are able to bridge cracks in concrete and, as such, can provide post-cracking strength. In this thesis, synthetic fibres made from organic polymers will be used, creating synthetic fibre reinforced concrete (SyFRC). In the last decade, the research effort of the scientific community focused on the structural response of FRC. Despite the growing research output, knowledge of the long-term structural behaviour still remains subpar. Limited research done on the subject suggested that the creep of steel FRC in tension is rather limited while the creep deformation of SyFRC is rather high and not admitted. This thesis will focus on the analysis of the structural response of synthetic fibre reinforced concrete under long-term tensile loading. This covers two topics. Firstly, the origin of creep will be determined. This topic focuses on what causes the experimental observations. Secondly, the development of creep in time will be investigated. The phenomenon can be described through multi-scale modelling. The response on the micro-, meso- and macro scale, for the fibre, the bond between fibre and matrix and the composite respectively, can be described both numerically and analytically. This thesis comprises both an experimental and a numerical/analytical part. The focus of this thesis can be put on either of these and depends on the student s personal preferences. For example, a more practically oriented thesis may focus on an optimization of the experimental setup. In this case, the numerical and analytical part may be rather limited. On the other hand, in a more numerically oriented thesis the student may concentrate on the modelling of the creep behaviour using finite elements. The interpretation and validation of new and existing models becomes of interest in this approach. Either way, the outcome of this thesis should encompass both a state of the art as well as a description of the insights gained throughout the year. Experimental setup Numerical model