Koenraad Van Balen

A value-based monitoring system to support heritage conservation planning

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 Belgium and the Universidad de Cuenca in Ecuador. A new management concept was developed throughout a five-year interdisciplinary and multi-actor growth process within an international setting. Design/methodology/approach – The application of the preventive conservation approach to world heritage management places the concepts of authenticity and integrity at the core of the heritage monitoring system. Moreover, the monitoring system is converted into a decision support tool for intervention and maintenance planning, beyond the mere purpose of inventorying or generating alerts. Findings – The regular update of information for condition, risks and value assessment st...

Hydraulicity in Historic Lime Mortars: A Review

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 is nearly identical. However, the classification of ancient hydraulic limes is mainly based on their chemistry, obtained from the analysis of ancient mortar binders. Moreover, it is shown that the phase composition of these limes evolves with time, making their classification uncertain and difficult.

Expert system for evaluation of deterioration of ancient brick masonry structures

The aim of the research on brick masonry degradation supported by the D.G. XII is presented. The project has delivered a damage atlas of ancient brick masonry, a book with a description of the types of damage, and their possible causes, in ancient brick masonry structures and Masonry Damage Diagnostic System (MDDS), an expert computer system allowing the user to define damage types and damage causes in ancient brick masonry structures. The scientific methodology used for the development of both documents is given. Illustration of the MDDS is done through explaining the type, processes and cause of damage that occurs to historic brick masonry structures related to air pollution and traffic.

Church of Saint-James at Leuven: Structural Assessment and Consolidation Measures

The construction of the western tower of the Church of Saint James dates to 1220. During several subsequent building phases, the Romanesque church has been replaced and extended by a church in early Gothic style. The wooden roofs in the central and side naves were replaced with masonry vaults, and flying buttresses were added. The structure itself is located on a swamp, reclaimed by the monks at the time of construction. The load-bearing capacity of the subsoil is limited, causing large differential settlements. At several occasions in the past, restoration works took place. Due to the excessive cracks observed however, it was decided in 1963 to close the church envisaging its structural collapse, to remove the severely cracked masonry vaults of the side naves and to shore up the pillars of the main nave. Additionally, in 2000, the remaining flying buttresses were removed and replaced by tie rods. The focus of this manuscript is on the structural understanding of this historical building, to determine the most appropriate strengthening and consolidation measures, respecting the authenticity of the building and preserving it for the future.

On-Site Stress Measurement on the Piers of the Saint Jacobs Church in Leuven, Belgium

The construction of the Saint Jacobs Church dates from 1220. During several subsequent building phases, the Romanesque church has been replaced and extended by a church in early Gothic style. Because of the location of the church, constructed on a swamp, and the unforeseen additional vertical loading on the columns of the main nave, large differential settlements took place. During a research campaign, the resulting stresses are determined both numerically and experimentally, based on a minor destructive “hole-drilling technique.” Numerical determination allows the deduction of the principal stresses (magnitude and direction) in stone masonry. The experimental technique is presented and the results are compared with the outcome of a comparative numerical analysis. The quality of the experimental technique and the usefulness of the on-site methodology in the framework of cultural heritage are presented and discussed.

Documentation in World Heritage conservation: Towards managing and mitigating change – the case studies of Petra and the Silk Roads

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 assessment of risks faced by World Heritage properties and threats to the integrity of the Outstanding Universal Values (OUV). With respect to the Silk Roads CHRIS case study the Geospatial Content Management System (Geo‐CMS) proposed aims to improve information management and collaboration among all stakeholders.Design/methodology/approach – Integrated surveying techniques and information management systems together with active stakeholder participation can be used as conservation and management tools. In the case of PAP, using a systematic documentation tool (MEGA‐J) to conduct site condition and risk assessment of cultural heritage and combining photographs, m...

Construction Materials from Stainless Steel Slags: Technical Aspects, Environmental Benefits, and Economic Opportunities

State‐of‐the‐art technologies that implement the industrial 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‐alkali‐activation. The technical, environmental, and economic features of three SS bricks - solid bricks, perforated bricks, and lightweight aerated blocks - are compared to commercially available construction materials. Although the produced bricks meet industrial standards, technical challenges, such as optimization of alkali addition and use of metal molds, should be dealt with before upscaling to industrial production. A cradle‐to‐gate life cycle assessment that aggregates the results of the various impact categories shows that the environmental impact of solid and perforated SS bricks is lower than the impact of conventional clay‐baked bricks owing to the avoidance of additives for slag stabilization and energy consumption for sintering clay. The impact of aerated SS bricks was found to be similar to the commercially available aerated blocks. More specifically, the carbon dioxide uptake from carbonation reduces the overall environmental impact, whereas use of alkalis increases the impact. A strengths weaknesses opportunity threats analysis highlights the economic advantages of SS bricks originating from lower energy requirements, reduced dependence on primary resources, and improved metal recovery from slag. However, in order to apply the innovative technologies at industrial scale, challenges related to processing conditions, feedstock variability, and potential competition from existing brick suppliers have to be overcome.

Flexural Performance of Small Fir and Pine Timber Beams Strengthened With Near-Surface Mounted Carbon-Fiber-Reinforced Polymer (NSM CFRP) Plates and Rods

Abstract 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 1.4 mm × 30 mm, four specimens strengthened with CFRP plate with the dimension of 2.8 mm × 30 mm, four specimens strengthened with one Φ6 mm CFRP rod, and four specimens strengthened with one Φ8 mm CFRP rod. The proportions of fir specimens and pine specimens are 50% and 50%. The results show that compared with the unstrengthened specimens, there is an improvement in flexural capacity and stiffness of the specimens strengthened with near-surface mounted CFRP plates and rods respectively. Finally, the calculation formulas of the flexural capacity of fir and pine timber beams strengthened with near-surface mounted CFRP plates and rods are presented.

Preventive Conservation of Historic Buildings

Preventive Conservation is argued to improve preservation of heritage at large. The UNESCO chair on Preventive Conservation, monitoring and maintenance of monuments and sites (PRECOM3OS) has pushed research and collaboration to understand the nature of preventive conservation in the field of built heritage. The study of the concepts and practices of prevention in public health helps to understand the systemic nature of prevention and how they can be transferred to the conservation world.

Water transport between mortar and brick: the influence of material parameters

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 simulated using a commercial control volume (CVM) software tool. Such simulations are made possible by a newly developed method to measure transport parameters of fresh mortars. The amount of water leaving the mortar in 1 h depends mostly on two parameters of the mortar: initial and residual water content. The rate of flow across the interface shows a complex behaviour and is larger for cement mortar and for strongly absorbing brick. The accuracy of simulations is somewhat limited by the importance of over-capillary effects in the bricks near the interface. It appears that this over-capillary water is partly distributed over the brick, and partly reabsorbed by the mortar.