Structural Synergy. Structural Engineering

(1)

Structural

Synergy

(2)

PhD Conference on Structural Engineering Structural Synergy

Aula Conference Centre, Mekelweg 5 2628 CC Delft. 12 September 2013

Edited by Damian Palin, TUD Arthur Slobbe, TUD Sayeda Nahar, TUD Sjors van Es, TUD Alexander Schmets, TUD Chi Zhang, TU/e Andrija Blagojević, TUD Yuan Zhang, TUD

Hatice Cigdem Demirel, TUD Frank Bijleveld, UT Delft University of Technology

Faculty of Civil Engineering and Geosciences Department of Structural Engineering Stevinweg 1,

2628 CN Delft

Graphic design Damian Palin, influenced by the work of Joseph Müller Brockmann

Font Helvetica

Logo and cover Three bridges in Rotterdam: Erasmusbrug, Willemsbrug and De Hef, representing three eras of structural engineering in the Netherlands.

Publisher Delft University of Technology Printing Sieca Repro,

Turbineweg 20, 2627 BP Delft ISBN 978-94-6186-203-7

Colophon

(3)

Word of welcome ii Introducing Structural Synergy iv

Sponsors viii

Keynote speakers and moderator 2 PhD contributions

Delft University of Technology

Integral Design 10

Materials and Environment 14 Road and Railway Engineering 48 Structural and Building Engineering 84

Structural Mechanics 108

Eindhoven University of Technology

Design System 116

Structural Design 124

University of Twente

Construction Management and Engineering 136

Organising committee 144

(4)

Word of welcome

Usually, PhD’s tend to meet colleagues from their own peer community, often highly specialized. A PhD on asphalt materials will join pavement engineering conferences, a life cycle BIM expert may present and publish in the IALCCE network and a PhD in concrete mechanics will feel at home at fib or IABSE symposia.

Less usual is that PhD’s from different disciplines open up, meet and mix. Structural Synergy is an initiative to do so. The objective is to bring together PhD’s from different disciplines, but for the same domain – in this case structural and building engineering. Structural Synergy will share a variety of research methods in experi-ments, computations, innovation and utilization for different materials and different structures, ranging from buildings, roads, railways, bridges, tunnels, to hydraulic, off-shore and other infrastructures.

Even less usual is that PhD’s take the initiative for such event themselves, bottom-up. In previous years Prof. Walraven and others organized PhD symposia in the Research School Bouw, but this time the PhD’s Arthur Slobbe, Damian Palin, Sjors van Es, Sayeda Nahar, Yuan Zhang, Cigdem Demirel, Andrija Blagojevic from TU Delft along with Chi Zhang from TU/e and Frank Bijleveld from UTwente originated the idea for themselves and organized it fluently, inspired and coached by Alexander Schmets from TU Delft. We sincerely thank all of them for that.

A second objective of Structural Synergy is to link the PhD researchers with practicing engineers. Industrial partners and stakeholders are eager to absorb new knowledge, new materials concepts, improved analysis techniques and structural innovations as they face new responsibilities in the dynamic sector nowadays. For this reason, practitioners have been invited. Structural Synergy is supported by and organized in conjunction with other parties, including:

• Support Campaign Civil Engineering, where the Ministry of Infrastructure and the Environment (Ri jkswaterstaat), the G4 major cities, over 15 major contractors and engineering consultants and the material supply industry stimulate structural and civil engineering both financially and in-kind;

• DIMI, the TU Delft Initiative on Infrastructures and Mobility, which is a multi-disciplinary platform where researchers from six different faculties focus on integral issues,

• InfraQuest, a joint action of Rijkswaterstaat, TNO and TU Delft to consolidate and strengthen knowl edge and competences in Roads and Structures;

• 3TU.Bouw for the Built Environment, one of the 9 competence centers of the 3TU federation, where the faculties of Civil Engineering and Geosciences and the faculty of Architecture from TU Delft, the faculty of Civil Engineering and Construction Management from UTwente and the faculty of Architec ture and the Built Environment from TU/e collaborate;

• STW, The Netherland’s Technology Foundation, linking science and utilization and financing PhD projects and programmes like IS2C, ExploRail;

(5)

• DCMat, the TU Delft multi-disciplinary platform for materials.

There is a large number of PhD’s attached to the above communities. At Structural Synergy selection of them will present their research to colleagues and practitioners, in highly interactive sessions with networking oppor-tunities and inspiring key-note lectures.

We sincerely thank all sponsors, speakers, participants and organizers and hope that Structural Synergy will serve as a major reference in identifying novel techniques for design and maintenance of structures and in transferring results from academic research to relevance in practice.

Jan Rots

Chairman Department of Structural Engineering Department, faculty of Civil Engineering and Geosciences, TU Delft

(6)

Introducing Structural Synergy

Welcome to Structural Synergy 2013, a conference dedicated to structural engineering science in all its aspects as taught and researched at the three technical universities in the Netherlands. Today structural is the common denominator, structural in the sense of reliably bearing, often variable and unknown, loads for (very) long periods of time.

The topic is necessarily very broad as it includes most of the more persistent man-made structural assets that surround us in everyday life, and whose reliable structural services are normally taken ‘as a law of nature’ by the general public. Compared to consumer products the service levels of structural assets are extremely high. Bridges with a structural failure rate comparable to that of normal office printers would be considered completely unacceptable, while a tunnel would never be built if they had a service life expectance comparable to the most long lasting functional products such as (certain) washing machines or Hi-Fi-systems. Meanwhile, structural assets together exceed in financial terms the balance of any global financial institution, or even the yearly budget of the Dutch government, many times. Thus, the importance and impact of the subject of Structural Synergy is self-evident. One could be tempted to think that the establishment of a Holland Structures and Building Centre (cf. the Holland Financial Centre) is of vital importance for the future of the Netherlands and the well-being of its citizens. Today is one of those opportunities were we can stand together, academics and industry, contractors and asset owners, students and experienced professionals: let’s synergise, structurally, and combine and cross-fertilize our expertise to solve future challenges, while being grateful and proud with everything achieved already by our colleagues of the past generations.

Topical pitches by PhD-Students

As mentioned before, today’s topic is very broad, entailing objects like buildings, bridges, hydraulic structures, roads and railways. But also the materials these structures are made of and economic, environmental, societal (e.g. hindrance) and safety aspects are considered. All this is underpinned by a framework of theoretical models, advanced modelling and experiments throughout the length scales, i.e. from nano to mega.

A selection of these topics will come along through 15 short (5-7 minutes) plenary pitches by PhD-students at various stages of their research. The topics of the pitch-sessions have been chosen from the perspective of specialisation: • fundamentals and advanced modelling (6 pitches) • architecture, i.e. ‘shape, form and perception’ come in (3 pitches) • full scale experimental studies (3 pitches) • materials: ageing and healing (3 pitches) Poster carousels

During a one day event it is impossible to highlight all subjects plenary. Therefore two dedicated, highly interac-tive ‘poster carousel’ sessions have been designed to allow all participants to take notice of the full scope of the event. Posters are grouped in five themes that are considered to be relevant from a societal perspective:

(7)

• economic efficiency and societal acceptance (orange) • reliability of structural assets (black) • durability of structural assets (purple) • sustainability of structural assets (green) • up-scaling and production of materials & structures (light blue) At a poster carousel session, first a short introduction will be delivered by a more senior academic staff member. Then the posters belonging to the themes will be visited and can be discussed with the ‘performing’ PhD-student. The session will rotate and themes are colour coded’. At the end all participants will have visited all themes, and will have had the opportunity to interact (and make initial contact) with the scientists that are engaged in the research work at a daily basis. The simple mechanics of the carousels will be explained in a plenary setting at the conference.

Keynote speakers

Structural Synergy will be moderated by Mrs Ionica Smeets, TU Delft alumnus and mathematician. She herself would have been an excellent keynote speaker, given her talent to explain the depth, importance and fun of mathematics to broader audiences without compromising the content of the mathematical idea. Prof Geert Dewulf will deliver the scientific keynote, addressing issues relevant to the field from the scientific point of view. Mr Ivo van Vulpen takes care of the inspirational keynote. Mr Van Vulpen, being involved in the team that discovered the Higgs boson, is completely off-topic here. Or isn’t he? It is multidisciplinary and cross-cultural collaboration that led to the grand scientific achievement of 2012. Isn’t that also our setting? And meanwhile we might learn something new, something fun and maybe something useful. Finally, Mr Dronkers, the ultimate asset builder, maintainer and manager of the Netherlands, will hold the professional key note, which may be in-spirational as well. As ‘CEO’ of Rijkswaterstaat he is responsible for a higher asset account than any worldwide bank. But these assets still function: how does this work?

Interaction Interaction, across sub-disciplines, across culture or nationalities (over 20) is key today. The plenary sessions, the carousels, the lunch and breaks will provide ample opportunity for this. At the end of the day there is a BBQ (with halal, kosher and vegetarian choices) at the premises of the Faculty of Civil Engineering and Geosci-ences (delivered by the students of Betondispuut). Everyone attending is invited there to close the day in an informal setting.

Thanks for being part of this, and see you at the next Structural Synergy!

The Structural Synergy Organising Team (10 people, 6 nationalities: Bangladesh, 2 China, Ireland, 4 Nether-lands, Serbia and Turkey).

(8)

Delft Infrastructures & Mobility Initiative (DIMI)

(9)

Steuncampagne CiTG

C O M P E T A N C E C E N T R E F O R R O A D S & S T R U C T U R E S

(10)

(11)

Keynote speakers

and moderator

(12)

Prof.dr.ir.

Bauke de Vries

Biography

Professor de Vries’ research mainly focuses on computer aided architectural design, product and process modelling, VR technology and interfaces and knowledge based systems. He is the director of 3TU.BOUW, the collaboration between the faculties related to the building industry of the three technical universities in The Netherlands.

Biography

Professor of Planning and Development, Head of Department of Construction Management and Engineering and vice dean at University of Twente Mr. Dewulf holds a PhD in social science from the University of Utrecht. After working as a senior consultant at TNO, he joined Twente University. He holds an assistant professorship at Delft University of Technology and was a visiting professor at Stanford University from 2012 to 2013. He has also played a key role in the formation of 3TU.BOUW.

Dr.ir

Ionica Smeets

Biography

Dr. Smeets studied applied mathematics at the Delft University of Technology and got a PhD at the University of Leiden. Currently she combines being a mathematician and a journalist. As such, she has made several TV-appearances at for example the popular Dutch TV-show De Wereld Draait Door. As a part of the duo ‘Wiskundemeisjes’ she promotes mathematics on a blog: http://www.wiskundemeisjes. nl/ and has a weekly column in De Volkskrant.

Affiliation

Professor of Urban Science and Systems and Chair of the Design Systems group at Eindhoven University of Technology and Director 3TU.BOUW.

Affiliation

Independent Mathematician and Journalist.

Affiliation

Professor of Planning and Development, Head of Department of Construction Management and Engineering and vice dean at University of Twente.

(13)

Prof.dr.

Geert Dewulf

Biography

Professor of Planning and Development, Head of Department of Construction Management and Engineering and vice dean at University of Twente Mr. Dewulf holds a PhD in social science from the University of Utrecht. After working as a senior consultant at TNO, he joined Twente University. He holds an assistant professorship at Delft University of Technology and was a visiting professor at Stanford University from 2012 to 2013. He has also played a key role in the formation of 3TU.BOUW.

Mr.ing.

Jan Hendrik

Dronkers

Biography

Mr Dronkers studied civil engineering, engineering management at the university of applied sciences. Later he studied law at the Erasmus University of Rotterdam. He has occupied various functions within the organisation of Rijkswaterstaat. In 2000 he became Chief Engineer-Director of the North Holland office in Haarlem. Since February 2010 he is the Director General of Rijkswaterstaat.

Affiliation

Director-General of Rijkswaterstaat.

Affiliation

Professor of Planning and Development, Head of Department of Construction Management and Engineering and vice dean at University of Twente.

(14)

Prof.dr.ir.

Jan Rots

Biography

Professor Rots studied civil engineering at TUDelft where he also got his masters. After a career TNO he joined the faculty of Architecture at Delft University of Technology as a professor in Structural Mechanics. Later he joined the Structural Mechanics section housed in the Civil Engineering faculty becoming head of the department of Structural Engineering in 2006.

Dr.

Ivo van Vulpen

Biography

Dr. van Vulpen is a particle physicist working at the National Institute for Subatomic Physics and University of Amsterdam. His research focuses, as a member of the Atlas experiment, on analysing proton-proton collissions at the LHC collider at CERN (Geneva). As a lecturer he teaches particle physiscs to bachelor and master students.

Affiliation

Head of department of Structural Engineering at Delft University of Technology.

Affiliation

Researcher at Nikhef and Associate Professor at University of Amsterdam.

(15)

Dr.

Ivo van Vulpen

Biography

Dr. van Vulpen is a particle physicist working at the National Institute for Subatomic Physics and University of Amsterdam. His research focuses, as a member of the Atlas experiment, on analysing proton-proton collissions at the LHC collider at CERN (Geneva). As a lecturer he teaches particle physiscs to bachelor and master students.

Affiliation

Researcher at Nikhef and Associate Professor at University of Amsterdam.

(16)

notes notes notes notes notes notes

s notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

(17)

notes notes notes notes notes notes

s notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes notes notes notes notes

notes notes notes notes

notes notes notes notes notes notes

(18)

(19)

Delft University of Technology

Integral Design

(20)

Dynamic contracting

mechanism

Hatice Cigdem

Demirel

Delft University of Technology Integral Design 2010-2014 +31152784774 [email protected]

Biography

Cigdem studied civil engineering and obtained Msc degree in Structural Engineering in 2009 at the Suleyman Demirel University in Turkey. She worked at CB&I in the Netherlands during her Msc. In 2010, she started to work at TU Delft as a PhD researcher. Her main research interest is in the development of contracting mechanism in the field of road networks.

Research

Road network systems can quickly become obsolete. Due to uncertainty and unexpected changes, transportation agencies tend to suffer from increased complexity and unsatisfactory functionality. The current financial changes and the new requirements in road network sector are causing asset managers and service providers to rethink their approaches. A number of initiatives have been taken in the Dutch road network system to deal with changing circumstances. In such situations, contracting of road infrastructures needs special attention. In the domain of decision-making this study aims to manage maintenance contracts of road network in a dynamic way.

Promotor

Prof.dr.ir. M.J.C.M Hertogh [email protected]

The relations between changing circumstances, road maintenance network, and the contracting practices.

(21)

Hatice Cigdem

Demirel

Delft University of Technology Integral Design 2010-2014 +31152784774 [email protected] An example of output specifications of Performance Based Contracting (Rijkswaterstaat).

(22)

(23)

Delft University of Technology

Materials and Environment

(24)

The thermal conversion of biomass to produce the primary product, energy, and the secondary product, BioCement clinker.

Towards the

development of a

CO

₂

-neutral cement,

BioCement

Natalie Carr

Delft University of Technology Materials and Environment 2012-2015 +31653550445 [email protected]

Biography

Natalie Carr began her studies at the University of California Berkeley where she obtained a bachelor’s degree in Architecture. Her education continued with a master’s degree from the Technical University of Munich in the field of civil engineering with a focus on building materials and chemistry.

Research

The theory behind this research project is that biomass can act as a source for functional clinker minerals as well as an energy source during the necessary biomass conversion. The two main objectives are to obtain a material comprised of hydraulic minerals from the ashes produced in the combustion of a blend of sustainable biomasses and waste-products and to adapt the raw materials and the sintering process so that the combustion is conducted in a way that also generates energy. After thermal conversion there will be two products; the primary product being energy and the secondary product being ashes. The ultimate goal is that these ashes will be capable of replacing a substantial part of traditional Portland cement in typical cement-based products such as concrete. The new BioCement will be designed to be superior to traditional Portland cement from an environmental viewpoint, with negligible CO2 emissions during its production.

Promotor

Dr. H. Jonkers [email protected]

Schematic representation of the sources of CO2_in traditional clinker production.

Mineral phases detected in a biomass blend fired at 1400C in a laboratory oven.

(25)

The thermal conversion of biomass to produce the primary product, energy, and the secondary product, BioCement clinker.

Natalie Carr

Schematic representation of the sources of CO2_in traditional clinker production.

(26)

Micro-scale shrinkage

coefficient as key

parameter in

meso-scale lattice models for

drying and

microcrack-simulations

Dragana

Jankovic

Delft University of Technology Materials and Environment 2004-Present +38733710045 [email protected]

Biography

Dragana received degree in Structural Civil

Engineering: M.Sc. (University of Central Florida) and B.Sc. (University of Sarajevo). After working in Civil Engineering companies in Sarajevo, Dragana moved to Iceland to work at Research Institute and private CE Company. Dragana came to TU Delft to work on her PhD research on multi-scaling and microcracking simulation in concrete. Currently lives in Sarajevo.

Research

Microcracking in cement paste initiates from early moisture flow–drying shrinkage phenomena and depends on the value of shrinkage coefficient. In order to generate a 2-D model for microcracking simulation, traditional “black box” macro-level modeling is replaced by coupling of meso-level models from Statistical Physics (Lattice Gas Automata, LGA and Lattice Fracture Model, LFM), with the shrinkage coefficient determined experimentally by Environmental Scanning Electron Microscope (ESEM) at micro-level. In that way scaling of material is introduced and drying results from different scales are coupled. Lattice Gas Automata is a type of Cellular Automata that can mimic moisture flow (drying) and change of moisture gradient due to drying of porous cementitious material. Lattice Fracture Model is used to induce microcracks due to ‘moisture load’ obtained from Lattice Gas. Shrinkage coefficient is obtained from uncracked, thin cement paste specimens, which are dried in ESEM.

Promotor

Prof.dr.ir. K. van Breugel [email protected]

Copromotor

Prof. D. Wolf-Gladrow [email protected]

Moisture flow diagram. Drying till 95000 LGA time-

Drying results in Lattice Gas Automata for the ratio (r = 1) at (above top) 10 and (above below) 20000 LGA time-steps.

(27)

Example of displacement due to drying from 98% to 20% RH, in the cement paste microstructure.

(28)

Bacterial concrete:

Precipitation and

influence on chloride

transport and

carbonation

Balqis Binti Md

Yunus

Delft University of Technology Materials and Environment 2013-2017 +31624432695 b.bintimdyunus@ tudelft.nl

Biography

Balqis Binti Md Yunus graduated from the Faculty of Civil Engineering at Universiti Teknologi MARA (UiTM), Malaysia and has involved in internship program at KAIST, Daejeon, South Korea during her final semester of Master program. Following this, she served UiTM for more than 4 years and actively involved in research work related to construction materials. Currently, she is a PhD candidate at TU Delft and started working on self-healing concrete since March 2013.

Research

Durability, in many situations is of as paramount importance as strength which has to be considered explicitly at the design stage. Self-healing is the most practical method to ensure maintenance and repair method would prolong the service life of the building hence reducing the frequency of maintenance and eventually the repair cost.

At present, bacteria-based healing agent indicated a bright prospect for repair of cracks in concrete as regained the mechanical properties. However, in most studies conducted for the self-healing concrete using bacteria, the two parameters of carbonation and ingress of chloride ions were not taken into consideration. In this research, the sensitivity of self-healing bacteria-based concrete with respect to carbonation and chloride under the influence of an applied load are the scope of interests. The new technique proposed expected to give quantitative information on the effect of given load combinations on service life of concrete.

Promotor

Prof.dr.ir. E. Schlangen [email protected]

The image shows the set-up for chloride penetration of specimens under compression (left) and tension (right).

(29)

The image shows the specimens subjected to (a) carbonation, (b) chloride penetration and (c) compression and chloride penetration.

A

C

(30)

Interface Properties

and Self-healing of

(ECC-like) Repair

Materials

Mladena Lukovic

Biography

Mladena graduated from structural department at Faculty of Civil Engineering in Belgrade, Serbia. She began her PhD: “Interface properties and self-healing of (SHCC-like) repair material” at TU Delft in November 2011.

Research

Durability of concrete repair, including all types of repairs and application of different materials, often shows problems. In order to improve its performance, complex behavior of the system with inevitable existence of the interface between two materials has to be understood.

Starting point for the research is a recently developed cement-based material, known as SHCC (Strain Hardening Cementitious Composite). Fine PVA fibers introduced in this material ensure high ductility and self-healing potential which makes it suitable for application in concrete repairs.

The micromechanical properties of the contact zone between two materials determine the performance and govern the failure mode of the repair system. On a higher scale, surface preparation of the concrete substrate, moisture transport between the two materials, extensibility and deformational capacity of the repair material are some of the most important parameters which have to be taken into account while designing appropriate repair system. In-depth knowledge of these parameters, both on microstructural and mesostructural level obtained through combined experimental and numerical approach is the aim of this study.

Promotor

Modeled crack pattern of two repair systems: with SHCC (up) and non- fiber reinforced repair material (down).

(31)

Bove shows the micromechanical properties measured by nanoindentation as an input for modeling inteface performance in direct tension test.

(32)

Bacteria-based

self-healing concrete:

From lab table to

outdoor application

Retrieval of healing agent particles after hardening of cement paste, without and with coating.

Renée Mors

Delft University of Technology Materials and Environment 2011-2015 [email protected]

Biography

After following courses in numerous tracks within the field of Building and Civil Engineering, curiosity led to a topic in the field of material development. Trying to bring bacteria-based self-healing concrete to the market asks for joining hands with multiple disciplines, enabling the combination of several personal interests into one project.

Research

Crack formation is common in concrete and typically related to durability. Crack percolation may lead to leakage problems or ingress of deleterious materials. Durability may be enhanced by preventing further ingress of water and other substances.

Since the year 2007 an experimental mortar mixture with self-healing capabilities has been developed in the Microlab. This mixture includes a two component additive, consisting of bacteria and organic mineral precursor compound, included in expanded clay particles serving as protective reservoir. Upon cracking and following ingress of water, bacteria are activated and convert incorporated organic compounds to calcium carbonate. Precipitation of calcium carbonate on the crack wall allows to seal and block cracks, reducing water permeability. The current research project aims to further develop products containing the two component additive in order to successfully apply the material outdoors. Challenging is the technical voluminous and economical production of the healing agent for full scale application.

Promotor

(33)

Large scale healing agent production.

(34)

Corrosion of steel in

cracked concrete

Corrosion behaviour of steel embedded in cracked concrete.

José Pacheco

Delft University of Technology Materials and Environment 2010-2014 +31152788990 j.pachecofarias@ tudelft.nl

Biography

José obtained his MSc degree in Structural Engineering at Delft University of Technology in 2010. During that period, he made an internship and graduation project at TNO Built Environment and Geosciences under supervision of Prof. dr. Rob B. Polder. Afterward, he was appointed as a PhD candidate on a IS2C project on corrosion of steel in cracked concrete.

Research

The service life span of concrete structures can be compromised when cracks allow fast ingress of chlorides in marine environment conditions. This project studies the influence of bending cracks on the corrosion behaviour of embedded reinforcing steel. Cracks are assessed by different means. It also involves the development of a experimental test procedure on chloride penetration and quantification in collaboration with other European laboratories. Finally, x-ray microanalysis is suggested as a tool for quantification of chlorides in concrete specimens.

Promotor

Prof.dr. R.B. Polder [email protected]

Copromotor

Dr. O. Çopuroğlu [email protected] Atomic ratio plots (from ESEM-EDS) on mortar with chlorides.

(35)

(36)

Bacterial spores

Healing agent Expanded clay particle

Concrete Seawater

Bacteria-based

self-healing concrete

for application in the

marine environment

Biography

Damian graduated form the mechanical engineering department at Imperial College London. Following this he worked at both the Singapore Institute of Manufacturing Technology and Nanyang Technical University, Singapore, where he was the lead researcher developing a biomining process to extract magnesium from desalination brine. He is began his PhD: ‘Bacteria-based self-healing concrete for application in the marine environment’ at TUDelft in September 2012.

Research

Many physical and chemical phenomena are usually interdependent and mutually reinforcing in the deterioration of marine exposed concrete: expansion and microcracking due to physical effects increases concrete permeability paving the way for deleterious chemical interactions between seawater, concrete and embedded steel reinforcement.

A novel approach to self-heal concrete is a bio-inspired technique, where bacteria immobilized in the concrete are activated through crack induced water ingress, forming a mineral healing precipitate. This work represents a reference on the way to developing bacteria-based self-healing concrete for application in the marine environment. The next phase will see the design and impregnation of a bacteria-based agent into mortar specimens, with the aim of exerting bacterial control over mineral precipitates for improved healing of concrete in the marine environment.

Promotor

Copromotor

Dr. H. Jonkers [email protected]

ESEM images showing the respective rhomboidal (A) and spicule (B) surface precipitates of CEM III/B specimens submerged for 84 days in fresh and sea water respectively.

Damian Palin

Delft University of Technology Materials and Environment 2012-2016 +31653550445 [email protected] http://www.ted.com/talks/ 84

A

B

(37)

Above is an illustrative reprisentation of our hypothesis, where control is placed on the healing material produced for improved bacteria-based healing.

Bacterial spores

Healing agent Expanded clay particle

Concrete Seawater Control of precipitates NO3- respiration Formation of Mg-carbonate (improved healing_material) Lower permebility

Larger crack width reduction Increased dura bility

self-healing

Bacteria-based

NO3 -2H+ H2O CO2_MgCa(CO 3)2 Mg2+ Mg2+ Ca2+ Organic carbon

Damian Palin

Delft University of Technology Materials and Environment 2012-2016 +31653550445 [email protected] http://www.ted.com/talks/

(38)

An integral in-situ

chloride sensing and

monitoring system for

concrete structures

Farhad Pargar

Biography

Having been received Master’s Degree of Hydraulic Structural engineering in 2006 at the University of Tehran, I participated in many research programs at the Construction Materials Institute (CMI), University of Tehran. Due to my deep interest to research works associated with concrete technology and new construction materials in structural engineering, I made my decision to apply for the PhD program in Department of Material & Environment at Technical University of Delft.

Research

Up to now there is no robust and reliable chloride sensor available in the market that can be can be used as the basis for a full continuous monitoring system and enables the possibility to measure the so-called chloride migration profiles continuously by means of a computer controlled system. It indicates the clear need for a robust, stable and long term performing Cl sensor system. With the Cl sensor that will be developed within the scope of this research project, a fully automatic measuring of the chloride content in the surface zone of a concrete asset becomes feasible and will partly replace currently used destructive measuring techniques. The sensor contributes to the automation of the condition-based maintenance of concrete structures and to enable the development of asset management systems.

Promotor

Schematic diagram ion transport in cement paste.

Integral in-situ chloride sensing and monitoring system for concrete structures.

(39)

Chloride-induced corrosion is one of the most important deterioration mechanisms in reinforced concrete structures.

(40)

Crack blocking by

swelling or melting

coated aggregates

Adhi

Priyambodho

Delft University of Technology Materials and Environment 2013-2017 +31645956779 b.a.priyambodo@ tudelft.nl

Biography

Adhi graduated from the Department of Civil Engineering at Gadjah Mada University (UGM) and continued his studies to take master of civil engineering at Diponegoro University (UNDIP). After receiving his master degree, he was a Junior Lecturer at Engineering Faculty, Civil Engineering Department, UNTIRTA, Indonesia and then started his PhD at Delft University of Technology (TU Delft) which is about “CRACK BLOCKING BY SWELLING OR MELTING COATED AGGREGATES.“ In January 2013, he started to work at TU Delft as a PhD researcher.

Research

The goal of this project is to produce a concrete in which cracks that develop in the material are blocked when water (or an other liquid) enters the crack or where the coating is activated and melts and by that blocks the crack. Cracks always follow the weakest link in the materials. In concrete this weakest link is mostly the bond between aggregates and cement matrix. If the aggregates are coated with a material that swells if in contact with water, then this swelling material can fill the crack and block the path through the concrete. Also the aggregates can be coated by a bitumen (with metallic particles) which can be heated by induction energy. Then the bitumen becomes a fluid and can block the cracks. For this recycled aggregates from asphalt can be used, which makes the product also sustainable.

The result of this project will be a new self healing concrete for special applications in which durability is very important (the reinforcement should be protected well) or in which the structure should retain a liquid, such as tunnels, storage tanks, industrial floors or slabs at gas-stations.

Promotor

Uncracked concrete. Cracked concrete.

(41)

The principle regarding the mechanism of the project blocking by swelling or melting coated aggregetes.

Cracked concrete: Concrete cracks through the interface between the large aggregates and the cement mortar.

Concrete with bitumen+steel wool swells

can be heated by induction energy. Rubber coating.

(42)

Experimental and

numerical investigation

of chloride ingress in

cracked concrete

Branko Savija

Biography

Branko graduated from Faculty of Civil Engineering at University of Belgrade, Serbia, with a diploma thesis in dynamics of structures. Following a stint as a student assistant at his alma mater, he joined Delft University in September 2010 to pursue a PhD in concrete durability, with a tentative thesis title: “Experimental and numerical investigation of chloride ingress in cracked concrete”.

Research

Chloride induced corrosion is the most important deterioration mechanism affecting reinforced concrete structures. It has been studied for decades already. Models to deal with the problem are readily available to engineers.

However, available models consider crack free concrete. In reality, this is never the case – concrete structures are designed to crack. This could change the speed with which aggressive chloride ions enter the concrete. Within this research, experiments and numerical modeling are employed in order to understand the coupling between mechanical cracking and chloride ion ingress.

When corrosion of reinforcement does occur, rust is created. It expands, causing stresses in the surrounding concrete. This leads to cracking, which is the first visible sign of ongoing deterioration. To study corrosion induced cracking of cover concrete, again the synergy between experiments and numerical modeling is employed. This study aims to broaden the knowledge relating the interdependence between cracking, chloride ingress, corrosion, and further deterioration.

Promotor

Chloride ingress in cracked concrete modeled using a lattice model.

(43)

Cracks in concrete induced by reinforcement corrosion captured using X-ray computed Tomography (a non-destructive method).

(44)

Porous Network

Concrete: a building

component to make

concrete structures

self-healing

Senot Sangadji

Delft University of Technology Materials and Environment 2010-2014 +31152788017 [email protected] senot.sangadji@gmail.

Biography

He received structural engineering master degree from Institut Teknologi Bandung, Indonesia. From 2010 he began his research on the development of porous network concrete, a novel method of to make concrete structures self-healing. Before he joined the research group in TU Delft, he was a junior lecturer at UNS, Indonesia, where he taught and conducted research in structural analysis, structural dynamics, and earthquake engineering.

Research

Self-healing concrete is a ‘promising technique’ for designing infrastructure that shows higher durability and have longer ‘maintenance free’ performance with low repair cost. Inspired by nature, this research aims to mimic bone morphology by embedding porous concrete in the concrete matrix. The system creates interconnected pores by which when cracks formed healing agent e.g. chemical-based, bacteria contained liquid, cement or mortar slurry can be injected to produce dense layer and seal the crack. A simple automatic on-off system, crack detected by sensors which then trigger actuating signal, is designed to implement autonomous engineered self-healing or self-repairing mechanism.

The experimental study found that concrete prisms specimens shows complete strength and stiffness regain for epoxy based healed but only 80% mechanical properties regain for bacteria based specimens. However, cracks were filled completely by epoxy resin as well as by bacteria based solution shown by 100% reduction of water permeability.

Promotor

A bone-like porous network concrete in which channels liquid healing agent top heal cracks in the concrete structure.

Epoxy based healed specimen shows complete crack healing which make second crack shift to weaker zone.

(45)

Imprint strongly indicate bacteria actively convert nutrients into Ca-based mineral products.

Epoxy based healed specimen shows complete crack healing which make second crack shift to weaker zone.