The construction industry significantly contributes to global greenhouse gas emissions, underscoringthe need for sustainable building practices. Floor systems, which comprise 68% [1] of building materials,are critical in determining environmental performance. Despite their importance, comprehensive Multi-Life Cycle Assessment (MLCA) of floor systems in the Dutch context are scarce. Given the importanceof these considerations, this study addresses the following research question:

”What are the structural and sustainability performance characteristics of different floorsystems used in buildings in the Netherlands when evaluated using a Multi-Life CycleAssessment (MLCA)?”

To address this main research question, a systematic MLCA framework was developed, integratingstructural and environmental performance evaluations. This framework was applied to evaluate threecommonly used floor systems: cast-in-situ concrete slabs, hollow core slabs, and deep deck compos-ite slabs. The methodology included parametrizing the design of these floor systems using Excel andGrasshopper, designing slabs for comparable load-bearing capacities, assessing environmental im-pacts using the Nationale Milieu Database (NMD) and GPR Materiaal, and accounting for degradationfactors such as reinforcement corrosion and concrete strength reduction.By applying the outlined methodology, the key findings of this study were identified and are explainedin this report, including:

• Adopting a circular building economy approach significantly reduces environmental impacts. Forexample, the prefabricated hollow core slab and deep deck composite slab reduced the Environ-mental Cost Indicator (ECI) by 78.06% and 87.10%, respectively, compared to the cast-in-situconcrete slab. These results highlight the advantages of material reuse and improved efficiency.

• The deep deck composite slab consistently achieved the lowest environmental impacts acrosscategories, requiring no additional interventions over three life cycles. In comparison, the hol-low core slab performed well but incurred higher impacts due to the environmental burden ofstrengthening measures.

• When evaluating performance across multiple life cycles, it is essential to consider long-termfactors such as material degradation. This study found that reinforcement corrosion in the hollowcore slab necessitated interventions, demonstrating the impact of degradation mechanisms onstructural integrity and environmental outcomes.

• While reuse feasibility shows promise, its scalability relies on robust inventory management, stan-dardized material passports, and design-for-disassembly practices.

These steps are critical toovercoming current barriers and realizing widespread adoption of circular construction principles.This research provides a robust MLCA framework and highlights the benefits of circular constructionprinciples, offering valuable insights for sustainable floor system design and reuse strategies in theconstruction industry.

Climate change and the growing need for energy independence have resulted in a quickly expanding offshore wind energy industry. Foundations of these structures made from welded steel hollow sections are prone to fatigue. The wrapped composite joints omit welds, greatly increasing fatigue life. But is this technology equipped to handle the harsh offshore environment?

This research aims to gain first insight into a subject not studied in the context of the wrapped composite joint before, the effect of freeze-thaw cycles. A broad overview is created by including a vast range of experimental and numerical subjects discussing the external degradation and internal degradation, through (microscopic) surface investigation, gravimetric measurements, quasi-static tensile tests and a numerical evaluation of heat transfer and developing strains on joint geometries.

Since more than a decade, TU Delft has been working on the development of bacteria
based self-healing concrete. The self-healing ability of the material is based on a
biological mechanism in which a limestone producing bacteria is added to the material
to repair cracks.
The purpose of this study was to understand and compare the efficiency of different
methods and materials used for incorporating bacteria into mortar. The aim of the study
was to create a self-healing mortar mix for practical applications.
Concrete is a widely used construction material. Most structural elements are made
using concrete and covered by a protective layer of mortar, called plaster. Cracks
usually propagate from the surface to the inside, which means that the plaster is the
first to crack. If the mortar is made self-healing, then the concrete underneath can be
better protected from the elements, and this could effectively increase the lifespan of
the structure.
For this project, fibre reinforced mortar is healed using bacteria (Bacillus Cohnii) which
is applied to the concrete using internal (different types of embedded capsules) and
external methods (paste applied to the cracks).
This is done to check the effectiveness of the bacteria in repairing damaged concrete
and to observe which method of application works best. The effectiveness is analysed
using optical and electron (BSE) microscopy and a permeability test to observe the
water tightness of the sample after cracking.
Additionally, characterization tests are performed on the capsules and performance
tests are carried on the mortar samples, to better understand their behaviour.
This study would help in making concrete structures more durable which would make
them more sustainable and cheaper in the long term.
This study found that crack healing is dependent on the crack width and the number of
capsules present in the material near the crack. The compressive and flexural strength
at 28 and 84 days was found to be higher in samples embedded with alginate capsules
and PLA capsules. External healing was found to be a good method for healing existing
materials but the healing was found to be dependent on the amount of paste that
adhered to the crack wall

Despite stringent safety standards, concrete is prone to various forms of deterioration over time, and the occurrence of cracks is not uncommon. Therefore, the detection and monitoring of deformations in concrete are essential to mitigate the risks associated with structural failure. Implementing a real-time Structural Health Monitoring (SHM) system can play a crucial role in identifying early signs of damage, such as corrosion in reinforcement, thus enhancing the efficiency of maintenance and repair interventions and ultimately prolonging the lifespan of the structure. The data collected through SHM techniques also contribute to the validation of design practices employed in the structure and further advancements in the field. In a broader context, the integration of SHM supports the development of sustainable infrastructure, ensuring the longevity and safety of concrete structures.
Along with visual inspection, SHM techniques are deployed to conduct a thorough analysis of structural behaviour. However, many traditional methods involve tedious installation processes. Several techniques utilize a wide spectrum of radiations, such as ultraviolet pulses, infrared radiations, and X-rays, and rely on sophisticated equipment that demands trained personnel for data analysis. In
this study, a novel approach is proposed for SHM by utilizing magnetic fields for
crack monitoring. Currently, this technique is used to monitor cracks in steel structures.
The aim of this work is to explore and adapt this idea to integrate the sensor system into the field of structural health monitoring for concrete structures. The scientific contributions made in this study include the investigation of the effects of crack propagation on the magnetic field, the modeling of the behavior using analytical and numerical methods, the construction of a prototype, the validation of the structural health monitoring technique, and the demonstration of the feasibility of this method.

This master's thesis provides knowledge on non-destructive testing of cement and supplementary cementitious materials composition in concrete with a handheld X-ray Fluorescence analyser.

Today, concrete production is responsible for 8% of the world’s CO2 emissions. Recycling concrete material can directly contribute to the reduction of CO2 emissions. This process is costly and time-consuming. A possible solution would be to use a handheld X-Ray fluorescence spectrometer on-site to determine the concrete chemical composition.

No existing research indicates if concrete identification with a handheld X-Ray Fluorescence analyser is possible. This thesis intends to prove that this technique can differentiate concrete with various chemical composition.

Fourteen concrete cubes of fourteen different chemical compositions were analysed to fulfil this objective. The fourteen compositions reflect the concrete design used in the Netherlands. Experimental programs conducted on the concrete revealed the impact of different factors on the results obtained from the handheld-XRF. These factors include measurement time, moisture, surface carbonation, and matrix effect. Each factor impacts various oxides in different proportions, leading to distinct patterns. After investigating their impacts, a protocol was written to test all the mixes. Finally, the reproducibility of the protocol was assessed, and the mixes were tested using the protocol.

The primary outcome of this thesis is proof that twelve of the fourteen mixes were differentiated based on their alumina content. This oxide proved to be less impacted by moisture and surface carbonation than the other oxides. The influence of the different factors on measurements was identified and quantified. These studies also revealed that twenty measurements were sufficient to identify the mixes. The protocol improved the control of the factors but also appeared limited by the concrete matrix.

A possible approach to circumvent this problem would be considering oxides content as thresholds rather than numbers. Determining these thresholds requires testing many samples. Another further study is the possibility of reducing the impact of moisture and surface carbonation on-site.

In this research, the effect of curing with different types of current, current densities/voltage intensity on mortar is studied. The main objective is to explore the outcomes of electric curing on the setting time of CEM-I mortar. For achieving the main objective, an electrical curing setup is designed to accommodate curing with direct current, alternating current and pulsed direct current and the conventional vicat apparatus and its test procedure are modified in order to carry out the testing while a sample is being cured with current. Additionally, the effect of passing current on material properties such as compressive strength and resistivity is also studied. The temperature development during the curing process has also been monitored in the research. The electric charge and power calculation are done, for possible current/voltage regimes. The experiments revealed that the setting time can be altered by electrical curing of CEM-I mortar. The influence of electric curing for the chosen curing period is not significant as revealed from the compressive strength testing while the development of resistivity and temperature reveals that there is a correlation between these two properties. The effect of electric power applied to a sample is reflected in the results of the setting times. In the last chapter the findings of the study are summarised and recommendations, keeping in mind the possibility of expanding research in this field of study, have been made.

Recycled concrete aggregates (RCA) have been recognized as a sustainable solution to satisfy the demand and address the environmental impacts of the concrete industry. However, construction engineers and contractors still have reservations about RCA due to their heterogeneous origin and lower quality compared to natural aggregates. It is essential to know the properties of the parent concrete, in particular its chemical composition, before demolishing concrete structures in order to identify the source of the raw materials. Despite its importance, this has never been done before. This thesis aims to analyze in-situ chemical composition of concrete and to identify the type of cement used in concrete structures by applying the non-destructive characterization technique of a handheld X-ray Fluorescence (hXRF) analyzer. To achieve this, laboratory experiments were performed to assess important factors in measuring cement paste and concrete surface chemical composition using the hXRF. These examined the impact of different water-to-cement (w/c) ratios, curing age, relative humidity, and carbonation on the chemical composition analysis with hXRF, and to gain valuable insights regarding the oxide concentrations of concrete and the most influential factors in hXRF measurements. The results indicated no impact on the chemical composition measurements with the hXRF despite the w/c ratios, the curing age, and carbonation. It was identified that higher relative humidity conditions than 75% affect the measurements with hXRF. Subsequently, three case studies were considered for the in-situ assessment of chemical composition. Conducting tests with hXRF demonstrated the device’s potential for analyzing concrete characteristic oxides (MgO, Al2O3, SiO2, SO3, CaO, Fe2O3). As a result, it facilitated cement-type recognition and provided valuable information regarding its opportunities and challenges. Drawing on insights from the literature review, laboratory experiments, and in-situ measurements, a guideline for in-situ testing of concrete composition was developed.

Energy piles are getting more attention for their sustainable and economic potential. The fluid pipes are integrated in the foundation piles, which makes it cost-attractive, but also relatively new to the Dutch geotechnical industry. By lowering the temperature limit of the anti-freeze fluid in the pipes the heat extraction and thereby also the necessary pile length can be optimized. However, the resulting thermal loads might influence the structural function and are therefore a main obstruction for the industry. Within this thesis three aspects of freezing-thawing of an axially compressed end-bearing energy pile are evaluated: (i) frost resistance of concrete, (ii) thermal analysis and (iii) geotechnical analysis. The objective is to work towards a conclusion on the degradation effects of freezing-thawing processes along the edge of an end-bearing energy pile and come up with practical advice for the design. The behaviour of the concrete is evaluated by literature, wherein the concrete thermal conductivity and mixture are key elements. For the thermal analysis a pile group simulation and a detailed single pile analysis is performed in Comsol Multiphysics. The soil stratigraphy is simplified and based on the Western part of the Netherlands. The input originates from the heat-cool demand of a single household related to the monthly gas usage in the Netherlands. Typical heat extraction for this specific case, i.e. long-term average amount of 7 W/m, for 7 years did not result in freezing temperatures at the edge of the most critical piles. Freezing occurred after an increased heat extraction until 10 W/m. Furthermore, the influence of daily cycles in the single pile analysis damped by the thermal resistance of the concrete pile. The geotechnical analysis is assessed in an axisymmetric model in Plaxis with and without a fully-coupled thermo-hydro-mechanical (THM) module. The first set of analyses with THM examines the influence of expansion and contraction of materials including phase changes, but without changes in soil mechanical and physical properties. Two situations are considered that are different in terms of the position of their neutral plane and negative shaft resistance. The resulting settlements can be distinguished as initial structural load and settlements due to thermal seasonal cycles, which fluctuate between 1 mm. A ratcheting behaviour was observed and resulted in a settlement of 12 and 3 mm over 5 years. However, the volumetric strain accumulation around the pile indicates unrealistic results in the THM module and conclude that the simulation of freezing-thawing cycles has to be done in a more advanced constitutive model which can capture freezing-thawing behaviour of soils. Within the second set of analyses the impact of the soil strength and stiffness due to a freezing-thawing cycle was investigated for the two situations to determine their effect on the pile behaviour in terms of load-displacement and shear distribution. The results indicate that effective cohesion is most influencing the pile behaviour and it indicates that no need exist to change the design approach of end-bearing piles as long as the potential negative shaft resistance along the pile over all layers above the bearing layer is included in the design calculation and considered fully mobilized.

In the last decade, maintenance and adaptive reuse, of the existing building stock, have gained ground in the construction sector. For the adaptive reuse of a building, it is required to analyze, meticulously, the existing structure. Unreinforced masonry structures are indicative of the Dutch built environment. For the assessment of their structural capacity, the European Standard EN 1996 is, currently, applied. Masonry walls of high slenderness, often, comprise the structure of existing buildings, in the Netherlands. It has been noticed that the EN 1996 norm underestimates the vertical resistance of slender walls. This study attempts to extend the applicability of the EN 1996 norm to slender masonry walls, since the norm serves for the assessment of existing structures. Particularly, the research objective is to find an appropriate verification method for existing slender masonry walls, in one-way bending. Literature research is, initially, conducted, with respect to alternative formulas for the calculation of the vertical resistance of slender masonry walls. The formula in the EN 1996 norm and the alternative formulas are reviewed, considering a case study. The case study is one of the slenderest interior masonry walls, that form the structure of a relevant existing building block in Amsterdam. The latter was constructed in the late 19th – early 20th century. The engineering firm STRACKEE BV Bouwadviesbureau provided the technical drawings of the building block. Reference values for the vertical resistance, of existing slender masonry walls, are necessary to develop an appropriate formula for their verification. Therefore, the next step of the research is the numerical analysis. The response of slender masonry walls, subjected to combined vertical and lateral loading, is estimated according to the results of FE analysis. The case study is the reference for the geometry of the FE model. Indicative, for the construction period, properties of masonry are the input for the initial material model. Further, models of slender masonry walls with different geometrical and material properties are analyzed. Specifically, a parametric study is done, to define the influence of geometrical and material properties on the vertical resistance. Based on the FE analysis results, a new formula is proposed. The formula estimates the vertical resistance of existing slender masonry walls, subjected to combined vertical and lateral loading.

Injection Bolts have been preferred for several reasons over other alternatives for the rehabilitation of old riveted steel bridges since 1970’s. More recently they have been used to obtain slip critical shear connections in new structures such as new bridges, large roofs, storm barriers and other structures exposed to cyclic loading. In addition, they are tested as a feasible alternative to traditional shear connectors in steel-concrete composite flooring systems, in combination with oversized holes in the flange of steel girder to allow reusability. On the grounds of this research a novel injection material was developed at T.U Delft, namely steel reinforced resin as an alternative to conventional resin allowed in the Netherlands for structural applications without compromising stiffness of connection. Due to limited research on fatigue of resins used in structural applications, in this study an initial attempt to investigate the cyclic behaviour of conventional and steel reinforced resin subjected to uniaxial compressive cyclic bearing stress, in confined conditions is performed. First, for this objective an experimental program using a tailor-made test setup was carried out, and the fatigue response in terms of slip over number of cycles for resin and steel reinforced resin in oversized holes of 6mm and 10mm was obtained. With this specimen configuration, is intended to reproduce as possible the stress state of double lap shear connection without endanger the fatigue cracking of steel parts. Frequency, stress ratio and other testing parameters that can influence the results have been chosen based on relative literature and assembly of setup. Three stress ranges used, with the maximum related to the recommended long term bearing stress for conventional resin, while the failure criterion was set at 0.3mm slip which is related to this long term bearing strength at the end of working life. Secondly, a numerical model of test set-up to investigate the static and quasi-static behaviour of specimens was developed and validated by the quasi static experimental results of initial stiffness of connection. Finally, through statistical treatment of test results fitted curves obtained, and characteristic curves with 95% probability of survival are proposed for both resin types and hole clearances based on probabilistic model of ASTM standard and probabilistic model proposed by Schneider and Maddox, using Student’s t distribution. On the basis of experimental results, large scattering was observed for both type of resins, and more prominent for the larger hole clearance and higher stress range. The reasons for this scatter are discussed and recommendations for future improvement of set-up are proposed. Due to scatter the results could not fully support the expectations that fatigue behaviour of steel reinforced resin is superior to that of conventional, as it is the case in static and creep behaviour. From a selection of specimens with limited scatter in 6mm oversized holes, a trend that connections with steel reinforced resin lead to less slip due to cyclic loads after 500.000 cycles was observed. From the numerical research on static models of specimens it was verified that the bearing stress state of resin layer is almost identical to that of the double lap shear connection of EN 1090-2 indicating a similar stress transfer mechanism. From the statistical evaluation of test data with ASTM probabilistic model the use of steel reinforced resin leads to higher fatigue endurance related to conventional resin in 10mm oversized hole, while the fatigue life of specimens with conventional resin decreased with larger hole clearance namely from 6 to 10mm.

Skid resistance is an important parameter for road safety and therefore it is essential to monitor the skid resistance of pavements. In the Netherlands, skid resistance is measured with either the RWS Skid Resistance Tester -measuring the longitudinal friction coefficient- or the Seitenkraft-Messverfahren (SKM) -measuring the sideway friction coefficient. The latter is nowadays the preferred measurement device by Rijkswaterstaat. Skid resistance depends much on the vehicle speed: the higher the speed, the lower the skid resistance. Furthermore, the texture of the surface influences the speed dependency. Because it is not always possible to measure the skid resistance at target speeds set by Rijkswaterstaat, there is a demand for a speed conversion model for the skid resistance measured with the SKM. The objective of this research is therefore formulated as follows: the development of a speed conversion model for the wet skid resistance, measured with the SKM at different speeds, taking into account the macrotexture of the road surface. The used dataset consists of 718 sections of 100 metre, measured at the Dutch road network. Measurements were performed at 10 different roads with different pavement layers: porous asphalt, concrete pavements, dense pavements and stone mastic asphalt. The mean profile depth of the pavements varies between 0.21 and 1.80 mm. The performed measuring speeds were 40, 60 and 80 km/h, and for few sections 30 km/h. Three regression methods were performed. Firstly, a multiple linear regression was performed. The datapoints consisted of combinations of two measurements at different speeds on identical 100 metre sections. The second method estimated per 100 metre section a zero speed intercept which was used as a reference point. The third method used multilevel modelling and includes a hierarchical structure. Concluded was that the multiple linear regression on speed combinations is inappropriate for the objective of this research, because of two reasons: the datapoints are dependent on each other, and information is lost by splitting the 100 metre sections into datapoints with combinations of two measurements. In the second method, problems arise with estimating the zero speed intercept. The third method is most appropriate for this research and the three-level structure fits best on the dataset. The first level contains the individual measurements on the 100 metre sections, performed at different measuring speeds. The second level consists of the 100 metre sections and the third level consist of the roads on which the measurements took place. The standard error of the model on the training data is 0.032 whereas the average change in skid resistance for two datapoints is 0.053. This average change includes conversions over a speed difference from 10 to 40 km/h. From a sensitivity analysis of the macrotexture it was concluded that if no macrotexture can be measured, it is advised to use a different model in which no macrotexture is included. Recommendations for further research include among others registering more accurately the type and age of the measured pavements and extending the dataset with measurements performed at low measuring speeds and on curved sections. Furthermore, it is recommended to perform a more comprehensive outlier analysis and to optimise the hierarchical structure.

Steel fibre reinforced concrete (SFRC) is nowadays used as a construction material for pavement and industrial floors in The Netherlands. The common used SFRC mixture, is concrete strength class C30/37 mixed with circa 35 kg/m3 of steel fibre.
The details of the concrete composition mixed with steel fibres are ignored. The mechanical tests result of the experimental program accomplished in this thesis emphasized on the decisive role of the concrete composition and quality on the mechanical properties.