Koenraad Van Balen

• PhD
• Professor (Full) at KU Leuven

The article proposes a methodology for assessing the development of damage in building structures, subjected to differential settlement and uplift, using the analysis of Interferometry Synthetic Aperture Radar (InSAR) data. The proposed methodology is targeted towards general applicability, capable of providing assessment results for measurements o...

Accessibility plays a main role among the aspects that contribute to the conservation of Cultural Heritage sites. Seismic stability, fragility of the artefacts, conflicts, deterioration, natural disasters, climate change and visitors’ impact are only some of the possible causes that might lead to the inaccessibility of a heritage site for both rese...

Historic masonry structures are particularly sensitive to differential soil settlements. These settlements may be caused by deformable soil, shallow or inadequate foundation, structural additions in the building and changes in the underground water table due to the large-scale land use change in urban areas. This paper deals with the numerical mode...

The present paper deals with the behavior of several types of mortar in masonry under compression. The quantification of the response of mortar to triaxial confinement afforded by the masonry units in the composite subjected to compressive stresses is paramount in the determination of the peak stress of wallettes and pillars under compression. This...

The structural analysis of buildings requires accurate spatial models. Additionally, spatial information on pathologies such as settlement-induced damage is paramount in the assessment of heritage assets. This spatial information is used as a basis for Finite Element Methods (FEM) to evaluate the stability of the structure. Traditional data acquisi...

Differential soil settlements can induce structural damage to patrimonial buildings, causing not only economic but also cultural value losses. In 1963, the Saint Jacob's church in Leuven was permanently closed to the public because of severe settlement-induced damage caused by insufficient bearing capacity of the foundation. Currently, the church i...

Purpose The effect of heritage on place attachment is assessed by understanding how people “value” their heritage environment. In addition, the purpose of this paper is to assess the effects of place attachment on residential and investment trends according to two different social groups: local inhabitants and foreign immigrants. Design/methodolo...

Purpose The purpose of this paper is to illustrate the assets of a preventive conservation approach for historical timber roof structures, as a means to improve the quality and durability of maintenance and repair interventions. Design/methodology/approach The advantages of a preventive approach for historical structures were identified based on...

Hybrid cements harnesses the potential of alkalis to increase the reactivity of SCMs and thus decreases the clinker factor. However, alkalis have varied effects on the reactivity of C3S, the major phase in clinker at various ages. Dedicated and extensive research has been carried out on the hydration mechanism of alite (impure C3S), but limited wor...

Effect of water to cement (w/c) ratio and temperature profiles on the densification of C-S-H (calcium silicate hydrate gel) and hydration kinetics of triclinic tricalcium silicate (C3S) is studied beyond the first day of hydration. Calorimetry and quantitative X-ray diffraction/Rietveld analysis show that degree of hydration is unaffected by w/c up...

In Europe alone, it is estimated that about 300 million tonnes of sediments need to be dredged each year. The dredged sediments used in this study originate from the port of Antwerp, Belgium, which is the second largest port in Europe. Each year about 450.000 tonnes (dry matter) of sediments are dredged and subsequently treated, sand-separated and...

Early age hydration kinetics of tricalcium silicate (C3S) is studied extensively because of its predominant effect in the early age hydration of Ordinary Portland cement (OPC). This paper focusses on modelling the effect of mixing different particle size distributions (PSD) on the hydration kinetics in the early ages. Three different PSDs of alite...

This contribution examines the challenges posed to the cultural heritage documentation community (the CIPA community and others) in implementing a preventive conservation approach of the built heritage in today’s society. The “DNA” of Preventive Conservation. Various authors so far support the argument that preventive conservation is an effective...

The ancient white bricks in the Yichun region occupy a special place in Chinese cultural heritage. In order to study the material properties of these unique bricks, a series of experimental studies were conducted, including measurement of density, compressive strength, thermal conductivity, chemical composition, phase composition, pore structure, m...

Alite (impure C3S) being the major and most reactive phase in ordinary portland cement has been studied extensively. This paper focuses on the mathematical modeling of new hypothesis developed, densified volumetric growth, applied to the main hydration peak in alite hydration. This hypothesis assumes a time and particle size-dependent growth rate a...

Dredging of ports, harbours and waterways generates large amounts of sediments that find few applications and need to be disposed of. The dredging sediments in this study originated from the port of Antwerp, contained mainly SiO 2 , CaO, Al 2 O 3 and Fe 2 O 3 and comprised as major mineral phases clays (2:1 clays and kaolinite), quartz, calcite and...

Dredging of ports, harbours and waterways generates vast amounts of sediments that find few applications and need to be disposed of. In the port of Antwerp, Belgium, each year 450,000 t (dry matter) of dredging sediments are mechanically dewatered and stockpiled. This paper investigates flash calcination of the clay-rich dredged sediments as a sust...

In order to study the calculation methods of shear behavior of reinforced concrete beams of Chinese modern reinforced concrete buildings, this paper carried out tests on the concrete compressive strength of 12 Chinese modern concrete buildings, the mechanical properties of 66 rebars from different Chinese modern concrete buildings, and the concrete...

In heritage conservation, a gap is often observed between the theory of conservation as a durable process that aims at the preservation of a historic building and the practice of restoration as a single intervention that aims at a fast and convincing result. This paper describes the proposed approach for the conservation of the main façade of the S...

In order to study the physical and mechanical performance of rebars in Chinese modern reinforced concrete buildings built in the Republic of China era from 1912 to 1949, 66 rebars including 36 rectangular rebars and 30 round rebars were collected from the different Chinese modern concrete buildings. Surface geometries, mechanical properties, chemic...

Many timber lounge bridges are found in the south of Zhejiang Province and the north of Fujian Province in China. The timber lounge bridge is a unique type of timber arch bridge structure worldwide. Most of these bridges have some damages due to the influence by environmental impact and human action. In order to scientifically preserve these timber...

State-of-the-art technologies that implement theindustrial ecology concept only make it to the market if environmental gains and economic benefits are significant. Therefore, the article investigates, in an interdisciplinary way, two innovative technologies that valorize stainless steel (SS) slags as block masonry (bricks): carbonation and thermo-a...

The evaluation of the initial quality and long-term durability of an intervention on a historic building proves to be complex. On the one hand, technical and functional requirements can be defined which will lead to recipes and intervention methods. On the other hand, the heritage repair principles such as reversibility, compatibility and retreatab...

Crystalline argon oxygen decarburization slag, in powdery form, was investigated for its hydration potential by alkali activation and curing at 80°C. Na-silicate and K-silicate of the same modulus were used as activators. Isothermal calorimetry at 80°C indicated exothermic reactions in the slag pastes. When the slag mortars were cured under steam a...

After direct mineral carbonation, a material rich in carbonates and with reduced quantities of free oxides is obtained. The aim of this work was to show that such materials can be used in the construction domain. Basic Oxygen Furnace (BOF) slag from the steelmaking process has been traditionally seen as unfit for bounded applications due to its pro...

Preventive Conservation is argued to improve preservation of heritage at large. The UNESCO chair on Preventive Conservation, monitoring and maintenance of monuments and sites (PRECOM

In the Port of Antwerp, 500.000 tonnes dry matter base (DM) of sediments need to be dredged each year to ensure the navigability of the waterways. Traditionally, these maintenance dredged sediments were disposed in settling ponds or underwater cells. However, due to near exhaustion of the existing storage capacity as well as the limited availabilit...

The binding properties of continuous casting stainless steel slag were studied when activated by a combination of Na silicate and 5 M NaOH as well as K silicate and 5 M KOH at steam curing temperatures of 60, 70, 80, 90, 100 and 110 °C. The slag mortars developed moderate compressive strength (∼5 MPa) at 60 °C which initially increased moderately a...

The aim of this work was to investigate the binding potential of non-hydraulic, crystalline continuous casting stainless steel slag, which is a by-product from stainless steel production, by alkali activation with sodium hydroxide and potassium hydroxide. Calorimetric analysis of the activated slag showed low cumulative heat evolution at 20 degrees...

The hydraulic behavior of synthetic merwinite was investigated after activation by two different methods, aiming to enhance its hydraulic activity which is weak in water. Mechanical activation, by means of extensive milling in a bead mill, led to amorphization of merwinite and a decrease in its crystallite size. The combined effect of higher specif...

La necesidad de contar con un Plan de Conservación Preventiva, resulta imprescindible dentro de los procesos de conservación del patrimonio. El presente artículo expone una metodología desarrollada por el Proyecto Ciudad Patrimonio Mundial, que contribuye a la elaboración de un Plan Piloto de Conservación Preventiva, desarrollada teniendo presente...

Non-stabilized Argon Oxygen Decarburisation (AODNS) slag in powdered form was examined for its carbon dioxide sequestration capacity and for its potential utilization in the fabrication of high value building materials. The curing of the sample was carried out in two accelerated carbonation environments: i) in a carbonation chamber, maintained at a...

Serial transnational World Heritage nominations are challenging the way cultural heritage has been managed and evaluated in the past. This type of nomination requires different methodologies and tools to improve the monitoring cycle from the beginning of the nomination towards the periodic reporting. The case study of the Silk Roads Cultural Herita...

In order to study the flexural performance of fir and pine timber beams strengthened with near-surface mounted carbon-fiber-reinforced polymer(CFRP) plates and rods, bending tests on 20 specimens are carried out, including four unstrengthened specimens, four specimens strengthened with CFRP plate with the dimension of 1.4mm×30mm, four specimens str...

In Chinese traditional timber buildings, stitching is a very common way. When the bearing capacity or the rigidity is not adequate, a timber beam is often strengthened with another beam with stitching method. The timber stitching beams are mainly of two types, including small-top-big-bottom type and big-top-small-bottom type respectively. In order...

Moisture is known to decrease the mechanical properties of brittle construction materials. The present study focuses on the influence of moisture on the mechanical behavior of ferruginous sandstone in order to understand and quantify this effect. The investigated Diestian and Brusselian ferruginous sandstone have frequently been applied in monument...

En las zonas rurales, la conservación del patrimonio construido enfrenta varias dificultades que conllevan aspectos tecnológicos, sociales y económicos. La posibilidad de que el patrimonio sea un agente de cohesión social y de desarrollo económico, y que a su vez genere iniciativas locales de mantenimiento, son temas claves tratados en el presente...

Purpose ‐ The purpose of this paper is to presents a conceptual framework for a value-based monitoring system that serves as the core element for heritage conservation planning of World Heritage Sites. It reports on the early stage of heritage management research within the PRECOM3OS framework, in collaboration with the University of Leuven in Belg...

The noble purpose, of sequestering carbon dioxide, would be insufficient for extending the process of mineral carbonation to an industrial scale, if the economical balance would not be a positive one. This is why, the material obtained after mineral carbonation process, should be valorized by using it in different domains, and hence reducing the ov...

This article investigates the effect of chemical composition and cooling rate during solidification on the mineralogy and hydraulic properties of synthetic stainless steel slags. Three synthetic slags, covering the range of typical chemical composition in industrial practice, were subjected to high cooling rates, by melt spinning granulation or que...

Serial transnational World Heritage nominations are challenging the way cultural heritage has been managed and evaluated in the past. Serial transnational World Heritage nominations are unique in that they consist of multiple sites listed as one property, distributed in different countries, involving a large diversity of stakeholders in the process...

This work is focused on exploring various cold and hot stage treatment paths of stainless steel slag as a tool to improve its hydraulic properties. At a cold stage, mechanical and chemical activation was applied on industrial stainless steel slag; and it was found that both activation methods effectively improve the reactivity of the studied slag....

Lime renders are of great importance not only to enhance the appearance of the buildings, but also to protect and preserve old masonries. They constitute a specialized system, composed of several layers, in which each of them depends on the others and carries out some specific functions in order to assure a suitable performance of the whole. Knowle...

This article deals with the phenomenon of the early water transport between fresh mortar and a dry brick. Two bricks with different transport parameters were considered in combination with two different mortars: a lime hydrate mortar and a cement mortar. Water transport was monitored during the first hour after contact using X-ray imaging and simul...

Phase and morphology evolution of CaCO3 precipitated during carbonation of lime pastes via the reaction Ca(OH)2 + CO2 → CaCO3 + H2O has been investigated under different conditions (pCO2 ≈ 10−3.5 atm at 60 % RH and 93 % RH; pCO2 = 1 atm at 93 % RH) using XRD, FTIR, TGA, and SEM. Simulations of the pore solution chemistry for different stages and co...

Underwater Cultural Heritage (UCH) as an outstanding division of the cultural heritage of humanity appears to be crucial and complicated when more general issues regarding preservation and conservation are raised. The essence of in situ preservation should be equally discussable for any kind of archaeological remains; on land or underwater. There i...

Purpose – The purpose of this paper is to discuss the application of documentation and recording techniques for World Heritage conservation using the case studies of the Petra Archeological Park (PAP) in Jordan and the Silk Roads Cultural Heritage Information System (CHRIS) in Central Asia. In the PAP case study, these techniques could aid in the a...

This article gives a summary of functional and performance requirements for renders and plasters for historic masonry (design, execution and maintenance). Specific attention has been paid to degradation effects, such as caused by salt crystallization and freeze-thaw cycling. Traditional as well as designed prefab mortars are considered for repair i...

This paper discusses the application of Information Management Systems (IMS) for documenting and monitoring World Heritage (WH) properties. The application of IMS in WH can support all stakeholders involved in conservation, and management of cultural heritage by more easily inventorying, mining and exchanging information from multiple sources based...

Risk management – as it has been defined – involves the decision-making process following a risk assessment (Ball, Watt, 2003). It is the process that involves managing to minimize losses and impacts on the significant of historic structures and to reach the balance between gaining and losing opportunities. This contribution explains the "heritage...

The understanding and safeguarding of Cultural Heritage involves the collection, storage and processing of all forms of relevant information pertaining to it. Whereas the heterogeneous sets of data help understanding the heritage monument or site; heritage data management is an essential task for the use, dissemination, protection and conservation...

The study of the rheological properties of lime suspensions is a useful means to evaluate the workability of lime mortars. In this work, we studied the flow behaviour of two industrial hydrated limes, one of calcitic and the other of dolomitic composition, by means of two types of rheometer with different geometry and setup mode. The obtained resul...

The technical properties of cement mortars containing natural fine aggregate that is replaced by lead blast furnace slag at 25 and 35% level were assessed at fixed water-to-cement (W/C) ratio and at fixed flow table value. The leachabilities of some toxic elements from the cement mortars were also assessed to test the environ-mental suitability of...

This publication and development of a risk management methodology is the result of the Risk Mapping Project in Petra, a project of the UNESCO Amman Office in partnership with the Raymond Lemaire International Centre for Conservation (RLICC) at the Katholieke Universiteit (KU) Leuven in Belgium and in cooperation with the Petra Development and Touri...

Risk management – as it has been defined – involves the decision-making process following a risk assessment (Ball, Watt, 2003). It is the process that involves managing to minimize losses and impacts on the significant of historic structures and to reach the balance between gaining and losing opportunities. This contribution explains the "heritage...

Courses dealing with Geographic Information Systems (GIS) have been available to the students at the KULeuven since more than 20 years (Hubeau et al. 2011). However, it was not until last year that due to the increasing demand from the students of the Master of Conservation of Monuments and Sites (MCMS) to become familiar with GIS, the Raymond Lema...

Natural hydraulic limes were used in ancient times and are still produced today. A comparison of the chemistry and mineralogy of currently available NHL2 and NHL5 limes indicate that there are no clear differences except for the amount of ‘undefined material’, mainly comprising an amorphous phase. The chemical composition of these different limes i...

This paper discusses the application of Information Management Systems (IMS) in cultural heritage. IMS offer a set of tools for understanding, inventorying and documenting national, regional and World Heritage properties. Information Management Systems can assist State Parties, stakeholders and heritage site managers involved in cultural heritage m...

Mortar samples from the Notre-Dame Cathedral at Tournai in Belgium have been investigated as part of a broader study considering the transition of ancient cities and their rural territories from Roman to late Roman society and the transformation to the early Middle Ages. Masonry mortars and mortars used for flooring have been studied from the Imper...

Looking around us, we notice the durability of masonry structures. A well-built masonry structure provides a long term sustainable solution by virtue of its durability, adaptability and maintainability. However, building practice has changed in the last 50 years: building speed and technology, rather than quality and durability, have become the maj...

a b s t r a c t Repair mortars used for restoration are assumed to be highly compatible with historic materials in terms of physical, chemical and mechanical properties in order to assure the durability of masonry on the long term. Compatibility criteria are defined based on the original mortar characteristics but the quality and the performance of...

The silk roads cultural heritage resource information system (CHRIS). Abstract. This paper discusses the application of Information Management Systems (IMS) in cultural heritage management illustrated by the case study of the Silk Roads. The Silk Roads CHRIS deals with the development of an information management system supporting the Central Asian...

The water transport properties of fresh mortar are determined using three experimental techniques which are common in soil science but new in this field of application: permeameter tests, suction tests and pressure plate tests. A description of the phase relations of mortars during drainage (moisture-loss) leads to an expression of the water retent...

A combined reaction of hydration and carbonation takes place in hydraulic lime and lime-pozzolana mortars. Hydration reactions are the first reaction and carbonation of lime is the complementary reaction in the strength gain. Competition between these two reactions can occur in lime-pozzolana mortars if the pozzolanic material has low reactivity wi...

In restoration works compatibility requirements of repair mortars are defined based on the original mortar characteristics, but the efficiency and the performance of the repair mortars after application on masonry are not generally evaluated. From this perspective, original mortars and repair mortars from two historic masonry structures were analyz...

The effective design of a mortar for repairing masonry depends on a clear understanding of its function within masonry. The functions of mortar materials in masonry are classified as bedding, pointing, grout, render, plaster and mortars for surface repairs. The requirements that each type of mortar must meet in service depend on its environmental e...

This contribution gives an overview of how materials valorisation fits into the overall scheme of Enhanced Landfill Mining and shows its relations with energy recovery, separation of material streams and carbon sequestration. As such there is a close link with the contributions of Lieve Helsen and Anouk Bosmans; Mieke Quaghebeur et al. and Ben Laen...