Research team

Expertise

Impact of noise reducing measures (noise screens and low-noise road surfaces) Surface characteristics of road surfaces (noise through CPX/SPB, texture, skid resistance) Mechanical properties of surface and base asphalt layers (resistance to rutting, ravelling, stiffness and fatigue, ...) Thermal properties of asphalt mixtures, with application in asphalt solar collectors (HEAL - heat exchanging asphalt layer) Crumb Rubber Modified Bitumen and Asphalt Asphalt and bitumen recycling Environmental noise and the impact of noise reducing measures on the quality of life

Investigation of Crack resistance and Healing in BITuminous materials (CrasHBIT) 01/01/2024 - 31/12/2027

Abstract

Crack resistance and healing are two of the most important mechanical properties of asphalt mixtures. Understanding these properties is essential in the design of cost-effective and sustainable road structures. To develop a fundamental understanding of the complex behavior of asphalt mixtures, research in the micro (bitumen) and meso (mortar) subscales is needed. Despite previous efforts, our fundamental understanding of the healing phenomenon remains limited. In the state-of-the-art, Atomic Force Microscopy (AFM) is used to observe the cracking and healing in the microscale. However, AFM imaging only provides data at a limited amount of experiment stages. Furthermore, cracking and healing are investigated by fatigue or fracture-based tests on larger scales which are extremely time-consuming. Lastly, in the currently available tests, it is often impossible to distinguish actual healing from recoveries due to other reversible phenomena. In this research, several novel methods are proposed to investigate these phenomena in both micro and mesoscales. In microscale, a novel testing procedure will capture the dynamic evolution of the microcracks using a Confocal Laser Scanning Microscope (CLSM). Furthermore, in the mesoscale, a Finite Element Method (FEM) is used to train a Convolutional Neural Network (CNN) capable of assessing cracking and healing in a bituminous mortar using the strain field recorded by Digital Image Correlation (DIC).

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  • Research Project

Citizen Science project 'De Oorzaak' 01/08/2023 - 30/06/2025

Abstract

From noise-sensitive areas to oases of silence: with the large-scale citizen science project De Oorzaak, De Morgen (DM), the University Hospital Antwerp (UZA) and UAntwerpen are focusing on noise and noise perception in an urban environment. In 2024-2025, we will investigate how residents of different neighborhoods in Antwerp, Ghent and Leuven appreciate the environmental noise present. By means of questionnaires (subjective), smart sound sensors (objective) and medical research (UAntwerpen and UZA) we will classify which sounds are heard, what sound level these sounds have, how these sounds are experienced and what impact they have on health, stress, sleep and quality of life.

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  • Research Project

Fate of Polymers in Recycled Asphalt: a Multiscale Approach. 01/01/2023 - 31/12/2026

Abstract

Surface asphalt mixtures contain polymer-modified bitumen (PMB), a performance-enhancing additive. Currently being downcycled, recycling this material would make use of its enhanced response. The main concerns are if the aged polymer can still provide the required performance when combined with virgin PMB and the formation of clusters of aggregate particles and aged bitumen that do not blend properly when recycled into new mixtures. This non-uniform distribution of components leads to localized areas of embrittled bitumen and deficient adhesion around clusters, which may result in a failure-prone material. The methodology proposed includes an in-depth investigation of the effect of aging on the long-term response of PMB blends. Furthermore, an innovative multiscale study on engineered mixtures will provide a fundamental understanding of the effect of particle clusters. The generated knowledge will then be used for mixture validation. The data generated will be used for establishing relationships between the different researched scales using theory-based machine learning. This project combines expertise from three top European institutions: University of Antwerp, EMPA, and Vienna University of Technology, with unique synergies to address the research questions posed. Such knowledge will enable developing means for reusing PMB asphalt layers for new high-performance pavements. Ultimately, the know-how will contribute to eliminate downcycling of this high-quality material.

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  • Research Project

IMproved Photocatalytic Activity of asphalt pavements with modified TiO2 Nano Technology (IMPATiO2NT). 01/10/2022 - 30/09/2026

Abstract

Industrial activities and road traffic are the main causes of the emission of pollutants such as SO2, NOx, and volatile organic compounds (VOCs). According to the World Health Organization, more than 90% of the world's population lives in places where pollutant concentrations exceed their limits. Devoted to the field of environmental remediation, heterogeneous photocatalysis mediated by semiconductors, such as TiO2, has recently attracted significant interest due to its capacity to efficiently convert solar energy into chemical energy which can photodegrade harmful pollutants. Several research studies achieved promising results related to the degradation of different pollutants emitted by fossil fuels used by road vehicles. Due to the huge surface area of photocatalytic asphalt pavements and its vicinity to the exhaust gases from automobiles, they are quoted as promising surfaces for the reduction of SO2, NOx, hydrocarbons and other VOCs present in the atmosphere, but also to photodegrade soot as the accumulation of cars' fuel combustion in areas with heavy traffic. For TiO2, this only occurs in the presence of Ultraviolet (UV) light from sun irradiation and moisture/O2. However, the sunlight is mostly composed of visible and infrared photons, with only about 3%–5% of the solar spectrum comprising the UV range. In this sense, one of the most important concerns reported in recent literature to obtain improved photocatalytic materials is the doping of TiO2 particles with different materials, such as Ce, Cu, and Fe. To obtain photocatalytic asphalt mixtures, three main techniques can be mentioned for applying the semiconductor materials to the asphalt mixtures: (i) spray coating, (ii) volume incorporation, and (iii) binder modification. Spray coating is most likely the most efficient functionalization technique, as it uses smaller amounts of semiconductor material that are all situated at the surface of the pavement. However, the immobilization of the semiconductor particles over the asphalt mixtures surface is still a major challenge. Binder modification leads to a lower photocatalytic efficiency, but it will provide a better immobilization and also improved rheological properties. A significant concern that should be considered as well in both application methods, is the dispersion of the TiO2 nanoparticles. Otherwise, they may agglomerate and, consequently, decrease the photocatalytic efficiency even further. In conclusion, the main objective of this project is to study the major challenges towards a solar-active photocatalytic asphalt mixture which is both efficient and durable. This includes implementing the latest developments regarding modified TiO2 nanoparticles and studying important aspects as dispersion and immobilization.

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  • Research Project

BITuminous Mortars: an Accelerated testing APproach (BITMA²P). 01/10/2022 - 30/09/2025

Abstract

Investigating the viscoelastic properties of bituminous mortars can lead to a better understanding of the mechanical behavior of asphalt mixtures and therefore, the design and construction of cost-effective and sustainable road structures. Even though bituminous mortar is considered as the missing link between binder and asphalt mixtures and is gaining increased worldwide attention, there are still no effective tests to quantify its viscoelastic behavior. The state-of-the-art methods to determine the properties of these materials are cyclic-loading tests, which are time-consuming and use classical measurement instruments that only provide a global view of the mechanical performance of the whole sample. In this research, novel accelerated testing procedures are proposed that use the full-field vibration response of the samples to estimate the complex modulus and fatigue properties of bituminous mortars. Different optical measurement techniques are used and combined to design and validate these novel methods. These methods will be a big step forward in the road engineering community since the testing time is reduced from hours/days to a few minutes. This offers the possibility to conduct research on more samples and improve the mixture designs. Furthermore, the full-field measurements with the combined optical systems can shed light on some of the highly investigated aspects of asphalt mixtures, such as blending efficiency, self-heating, and the location of microcracks.

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  • Research Project

Purchase of an Asphalt Mixture Performance Tester (AMPT). 01/06/2022 - 31/05/2024

Abstract

Nowadays a lot of attention is being paid to the service life of new asphalt pavements; the mechanical performance of asphalt mixtures in the short and long term are always included in new projects of our research group. The testing of the dynamic modulus and fatigue resistance are two important ways to describe the mechanical properties of an asphalt mixture. In order to do so, the research group purchased a UTM (Universal Testing Machine) in 2017. However, this device, which has become very important in our research strategy in the last few years, has limitations in terms of technical specifications on the one hand, and availability due to frequent use on the other hand). In order to overcome these limitations and to guarantee the continuity of our research activities, a new device is purchased in this project to determine the performance of asphalt mixtures more advanced. The device in question is, among other tests, able to perform dynamic modulus and fatigue life tests according to the AASHTO standards, which are international references. The necessary accessories and set-ups for carrying out the intended tests are included in this project proposal.

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  • Research Project

In-depth study "Heat from Asphalt". 12/07/2022 - 31/12/2022

Abstract

The province of Utrecht (the Netherlands) is considering the large-scale application of asphalt collectors in the reconstruction of the N233 Rondweg-Oost in Veenendaal. The sustainable heat to be generated by the asphalt could be used to heat homes in adjacent residential areas. An exploratory study has already been carried out into the technical-economic feasibility of the concept. Based on the results of this study, the Province sees opportunities, but now also needs to go deeper. TNO (the Netherlands) and the University of Antwerp have been asked to carry out this in-depth study.

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    • Research Project

    BITuminous Mortars: an Accelerated testing APproach (BITMA²P). 01/10/2021 - 30/09/2022

    Abstract

    Bituminous mortar is considered as the missing link between binder and asphalt mixtures and has gained worldwide attention over the past decade. Investigating the mechanical properties of bituminous mortars can lead to a better understanding of the mechanical behavior of asphalt mixtures and therefore, the design and construction of cost-effective and sustainable road structures. The state-of-the-art tests to find the properties of these materials are cyclic-loading tests, which are time-consuming and use classical measurement instruments that only provide a global view on the mechanical properties of the whole sample. In this research, novel accelerated mechanical testing procedures are proposed that use the full-field vibration of the samples to estimate the complex modulus of elasticity, fatigue properties, and healing potential of the investigated bituminous mortars. Different optical measurement techniques are used and combined to design and validate these novel methods. These methods can be a big step forward in the road engineering community since the testing time is reduced from hours/days to a few minutes. This offers the possibility to conduct research on many more samples and improve the mixture designs. Furthermore, the full-field measurements with the combined optical systems can shed light on some of the highly investigated aspects of asphalt mixtures such as blending efficiency, self-heating, or the localized healing of microcracks.

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      • Research Project

      Zinc-co-Sink, dual pathway for safe rubber granulate recycling. 01/01/2021 - 01/05/2023

      Abstract

      This project is being carried out by the University of Antwerp and VITO, and supported by the Belgian Road Research Centre (BRRC). Two possible solutions are being investigated to prevent the release of zinc from rubber granules; on the one hand by coating the rubber granules (UAntwerp) and on the other hand by trapping the released harmful components in a sorbent before they are released into the environment (VITO). Possible solutions can, be developed further at a later stage (phase II) and can be used for many applications of rubber granulates where environmental problems play a role. In the follow-up research, attention will also be paid to the recyclability and durability of both solutions (influence of ageing and/or exceptional weather conditions).

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      • Research Project

      Expert Group - Assessment of new Crumb Rubber proposals. 01/01/2021 - 31/12/2021

      Abstract

      Assessment of new Crumb rubber (CR) proposals for Green.er The aims of this project are the following: 1. A summary of the relevant legislation when using crumb rubber as a building material for Flanders, Walloon region, Brussels and the European Union; 2. A position paper on ecotoxicity regarding the possible risks of combinations of toxic substances, even when the individual contaminants are within their quality standards incorporated in legislation. The document will inform on ecotoxicological risk related to substances and mixtures, on expected changes in legislation (e.g. surface water), and methodologies related to ecotoxicological risk assessment; 3. A checklist for new applicants related to environmental concerns (leaching, VOC emissions, ecotoxicity, …); 4. Assessment of new project proposals for Greener by a group of experts, limited to the potential environmental impact.

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        • Research Project

        Sustainable foundations through in situ recycling with foamed bitumen technology (FOAM) 01/11/2020 - 30/10/2022

        Abstract

        In Flanders, more and more attention is being paid to sustainable road structures, but rather to the pavement. In the next decades, we will also have to renew the foundations and sub-foundations of existing roads in the most sustainable way possible. Only this will allow us to perpetuate our road infrastructure, which is of primary economic and social importance, for generations to come. Abroad, we see more and more innovative use of materials for foundations: new material types (e.g geopolymers) and production technologies (e.g. emulsions, foamed bitumen). In this project, one of the promising innovative technologies was deployed: recycling old asphalt pavements into bonded foundations with foamed bitumen technology. With this technology, the existing asphalt is first milled off and crushed into an aggregate. The aggregate is then processed with a hydraulic binder and foamed bitumen to form a semi-bound mixture (FOAM). FOAM is then transported to the site and compacted (cold), just like unbound foundation material. Optionally, the process can even be done in situ, with emulsion and the foundation present. In this project, the asphalt was crushed and reduced to granules near the job site and mixed in ambient temperature to form a bitumen-bonded mixture. Being able to mill, mix and process on site mainly saves transport, leading to a lower environmental impact and economic balance. This project included a market study, an elaborated lab methodology to design quality mixtures with an alternative compaction that is more applicable to contractors, process control guidelines, an elaborated road design methodology with standard structures, the construction of two trial sections with different sections and a comprehensive LCA-LCCA calculation showing that this road structure is a favourable alternative to bonded and unbonded foundations. The use of FOAM allows more road construction materials to be economically recycled on site, with equivalent mechanical quality and less environmental impact.

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          • Research Project

          CRUMBit Phase 2. 01/09/2020 - 31/08/2023

          Abstract

          The main aim of this research is to identify the barriers preventing the use of recycled tire rubber in Belgian asphalt road surfaces and to develop market-ready solutions that can be presented to road authorities. The main expected results within the second phase of this project are the following: scaling up of the rubber modified bitumen to asphalt applications, leaching tests, analysis of the recyclability and an LCA/LCC study of rubber modified asphalt. The final work package includes the necessary follow-up steps to install the final product in one or more test tracks and finally get it approved for the Belgian market.

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          • Research Project

          Photocatalytic Asphalt Pavements for the Port of Antwerp (PAPPoA): a feasibility study (Port of the future). 01/03/2020 - 30/12/2021

          Abstract

          Asphalt pavements need to be able to withstand the effects of weather (i.e. UV, rain, and freeze-thaw cycles) and (heavy) traffic loading during their service life, while maintaining the necessary mechanical performance, e.g. limited rutting, fatigue resistance and water resistance, and providing comfortable and safe driving conditions in terms of the surface properties, taking into account mostly skid resistance and texture. Recently, not only investigations related to the mechanical performance or overall environmental impact of asphalt pavements are conducted, but more attention is given towards smart pavements, e.g. photocatalytic pavements. In most cases, TiO2 nanoparticles (semiconductor material) are used in the field of photocatalysis for many purposes, mostly for air and water-pollutant photocatalytic degradation, as it is effective, non-toxic, easily available and cheap. Due to the huge surface area of road pavements and its vicinity to the exhaust gases from automobiles, the photocatalytic capability is quoted as promising for air-cleaning. TiO2 is able to react under UV-light (only 3-5% of the sunlight spectrum) with pollutant gases, such as NOx and SO2, creating water-soluble nitrates and sulfates respectively, which are easily removed from the asphalt pavement by rain. It also has the potential to degrade soot, (spilled) oil and volatile organic compounds (VOC). In this project, we want i) to further investigate further the effects of traffic on the photocatalytic efficiency, ii) to determine possible effects on traffic safety (skid resistance) and iii) to develop an in-situ test setup to measure the NOx reduction.

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            • Research Project

            Purchase of a gyratory compactor for asphalt samples. 01/01/2020 - 31/12/2021

            Abstract

            As both present gyratory compactors are at the end of their lifespan (purchase in 2000 and 2008), with numerous calibration issues and temporary failure, a new gyratory compactor for research purposes is budgetted on this project. This device is essential as a first step in asphalt research as many standardized test methods, such as fatigue and water sensitivity, have to use specimens compacted according to EN 12697-31. With this device, cylindrical asphalt test pieces with a diameter of 100 or 150 mm are compacted, including the real-time monitoring and measurement of important research parameters such as the percentage of air voids and the shear stress. In addition, the height and apparent volumetric mass of the specimen can be checked and displayed. All necessary accessories such as molds for both standard and warm mix asphalt mixtures are included in this project proposal.

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              • Research Project

              AQ²UABIT – Advanced Qualitative and QUantitative surface Analysis of BITuminous binders using laser scanning confocal microscopy. 01/01/2020 - 31/12/2021

              Abstract

              In this project, an innovative methodology is developed by using Laser Scanning Confocal Microscope (LSCM) to investigate the behaviour of bituminous binders and mortar under specific physical and mechanical conditions including the impact of several additives. Bitumen, an oil derivate, is an important binder used in asphalt mixtures, roofing materials and emulsions. Regarding the circular economy, a higher recycling rate and increased service life is expected for future application, as it provides both economic and ecological benefits: a base layer with 40% reclaimed asphalt is about 25% cheaper and its total environmental impact is reduced by 6% (based on an LCA-study). An increased service life and quality avoids mobility problems, damage, fast deterioration etc. In most cases, both aspects are proven by mechanical tests in laboratory. However, efficient use of this material demands more and more scientific insight in the fundamental structural behaviour of bitumen. In order to enhance the current sustainability vision of 'closing loops', besides the mechanical properties, also the physico-chemical aspects must be taken into account, especially for higher recycling rates, fibre reinforcement, and additives improving healing and fatigue resistance. Moreover, both the development of innovative technologies, such as smart fibres in bitumen, and understanding the behaviour of the bituminous mixture, e.g. the ageing mechanism, need validated physico-chemical models. In this project, both methodologies, mechanical and physico-chemical aspects, are used to investigate the properties of the same bituminous samples (bitumen and mortar). A new technology is introduced and validated: the latest Laser Scanning Confocal Microscope (LSCM) allows for measurements across a 50 mm area with nanometre resolution (5 nm in Z-direction and 10 nm in the XY-direction). This technology allows to scan quickly (5 s measurement time) the bitumen surface in order to visualize aspects like bee structures (wax content) and bitumen coverage (adhesion between binder and granulate). Furthermore, the surface profile and film thicknesses are measured as well, which is important in the analysis of bitumen blending. Lastly, by combining these qualitative images with the Digital Image Correlation (DIC) methodology, it will be possible to obtain detailed quantitative results and to track changes in the bituminous mixture on a nanometre scale, e.g. during blending or healing. This technology will be used, together with mechanical tests (Dynamic Shear Rheometer, Direct tensile tests, Fraass bending point) to investigate the ageing/healing process, blending of old and new bitumen during recycling, and optimized use of additives, such as fibres, crumb rubber and rejuvenators. The project is divided into three steps: - integration of this new high-tech equipment, especially adjusted for bitumen research, in our bitumen laboratory, including Matlab software for data analysis; - development of a methodology for testing bituminous samples using an LSCM to fully understand bitumen morphology and physico-chemical mechanisms, related to ageing/healing, improved use of additives and as verification for mechanical tests. An opensource database of 6 binders, containing the physico-chemical and rheological properties, will be available and a secured database with the special binders will be available for collaborative research. - valorisation trajectories for designing new materials in a bituminous matrix, such as smart fibres or enhanced crumb rubber modified bitumen.

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                • Research Project

                Automated inspection of infrastructure using drones (AutoDrone) 01/10/2019 - 31/12/2021

                Abstract

                In this project we will use drones to detect and monitor damage in infrastructure: wind turbines, bridges, buildings, solar panels, pavements, etc. Firstly, an overview of available path planning tools will be given. Secondly, we will develop machine learning tools to automatically detect damage (cracks, potholes, corrosion). The third aim of the project is the development of a methodology to allow a systematic comparison of repeated drone based camera measurements. During the project 9 case studies will be performed. The project is performed by UAntwerpen and WTCB together with a large consortium of companies active in drone based inspections or owners of infrastructure.

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                • Research Project

                Crumb rubber modified bitumen (CRUMBit). 27/05/2019 - 30/06/2020

                Abstract

                The main purpose of this research is to identify the barriers which inhibit currently the use of tyre-derived crumb rubber in Belgian asphalt roads and to develop different market-ready solutions that can be introduced to the road authorities. The main expected results for phase I of this research are the following: detection of possible toxicity and health issues when using crumb rubber as bitumen modification (e.g. measurement of the volatile organic compounds or VOCs) and comparison of the mechanical and rheological properties of crumb rubber modified bitumen (CRmB) with commercial polymer modified bitumen (PmB).

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                  • Research Project

                  The impact of road degradation and traffic noise interventions on the quality of life. 01/04/2019 - 30/03/2020

                  Abstract

                  In a recent publication by the World Health Organisation it is recommended to keep (weighted) traffic noise levels during the whole day (Lden) below 53 dB(A) and during the night (Lnight) below 45 dB(A). As these new recommendations are stricter than the previous ones, an increase of (traffic) noise interventions can be expected in Belgium and Europe. Recent research also states that the effectiveness of traffic noise interventions on human health has been investigated in only a limited amount of studies. It is therefore important to further investigate this link. In this project, an answer to this question will be given regarding two types of noise interventions: low noise road surfaces and noise barriers. This will be achieved by combining already available results from acoustic measurements and surveys with results from detailed case-specific noise maps (Lden and Lnight), calculated in IMMI. Two test locations with so-called thin noise-reducing asphalt layers, five control streets (all streets located in Antwerp) and seven locations equipped with noise barriers (across Flanders) are part of this research. A second objective is to determine the impact of the degradation of road surfaces on environmental noise maps, by using available CPX-results as input for noise maps of a city center, and by evaluating the sound files with psycho-acoustic descriptors and in listening tests. A database with different CPX-sound files will be constructed first (differences in speed, type of pavement surface, age and number of defects …), before analysing them using the Psysound Matlab toolbox.

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                    • Research Project

                    Characterization of advanced materials using hybrid inverse modelling from full-field optical vibration measurements. 01/11/2015 - 31/10/2019

                    Abstract

                    Quantitative values for mechanical properties of materials are required in the simulation of the behavior of structures and systems in several engineering domains: civil engineering (buildings, bridges, roads, …), mechanical engineering (aircraft, cars, …), biomedical engineering (implants, scaffolds, etc.) and electronic engineering (semiconductor materials). In addition, the knowledge of these material properties provides a means to follow-up the health of a structure or system during operation and to estimate the remaining lifetime. The proposed novel hybrid material characterization method combines two distinct approaches to estimate mechanical material parameters, which has never been attempted before. By using laser Doppler vibrometry for the optical measurement of both resonating (at low frequencies) and propagating surface waves (at high frequencies), modal parameters and wave propagation characteristics can be derived simultaneously. By comparing these results with Finite Element and analytical models and by using an inverse modelling approach with intelligent optimization algorithms, it will be possible to identify more material parameters with an improved accuracy in a reduced measuring time. This will allow applications on more complex materials (e.g. layered poro-elastic road surface) in an in-situ environment. The proposed method will lead to several innovations, in the fields of measuring, data processing and optimization, and will be validated in three different applications: asphalt pavements (civil engineering), composite materials (mechanical engineering), and a tympanic membrane and bone material (biomedical engineering).

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                      • Research Project

                      Preliminary study into the economic and technical feasibillty of the use of river sludge in bitumen bound materials 07/10/2014 - 28/02/2016

                      Abstract

                      This project represents a formal research agreement between UA and on the other hand the Flemish Public Service. UA provides the Flemish Public Service research results mentioned in the title of the project under the conditions as stipulated in this contract.

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                        • Research Project

                        Pilot project Quiet Road Surfaces: technical guidance and implementation monitoring program. 01/09/2014 - 31/12/2017

                        Abstract

                        This project represents a formal research agreement between UA and on the other hand City of Antwerp. UA provides City of Antwerp research results mentioned in the title of the project under the conditions as stipulated in this contract.

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                          • Research Project