Istanbul’s historic and diverse architecture provided a fitting setting for the 11th International Conference on Durability of Building Materials and Components (11DBMC).
Istanbul provides constant reminders that we inherit our built environment from the past and often use it in unforeseen ways. Examples include the famous Hagia Sophia, a Byzantine church that became a mosque and is now a museum, and lavish Ottoman palaces converted into equally luxurious modern hotels.
Given these precedents for building longevity and adaptive use, Istanbul provided an appropriate setting for discussing durability. The 11DBMC was the latest in a series of triennial conferences devoted to exchanging ideas and research findings about the service life and durability of construction components and systems.
Presentations were given by 240 contributors from 43 countries, covering a wide variety of topics. These ranged from the specialist and material specific, such as ‘Chloride threshold determination in prestressing beams’, to the broadly philosophical, like ‘Implementing durability knowledge’. Such variety reflected the range of attendees, which included manufacturers, facilities managers and architects, as well as researchers. Despite the diversity of content, several clear themes were evident.
Thirty years has elapsed since the first 11DBMC conference, but the need for materials research remains as strong as ever, although participants complained that funding was hard to get. These drivers include:
- an increased emphasis on ‘sustainable’ construction
- revaluing of construction engineering, with maintenance and renovation of existing assets becoming as significant to the industry as new buildings
- the importance of performance-based building codes in an age of globalisation and open markets
- continued product innovation and evolution.
Durability in life cycle analysis
It was apparent from the many facilities managers’ presentations that methodologies for robust life cycle analysis of constructed assets remain a concern. Consideration of durability as the core component of sustainability is an unavoidable part of these processes. Regardless of how you quantify resource depletion or environmental degradation, the timeframe for the analysis is the design life of the building. Thus the sustainability of high-embodied-energy building components may be better than lower energy components with a shorter life. Conversely, there’s no point paying an additional environmental cost for a component whose serviceable life exceeds the intended life of the building.
Similar considerations apply to maintenance planning, where the desire to reduce life cycle costs is feeding a huge demand for better techniques to predict when, where and why durability failures occur.
New product innovation rare
Genuinely new product innovation in construction remains relatively rare. One example discussed was the possibility of regenerating spent silica aerogel filters into insulating panels.
However, there is a continual need for product assessment and verification as familiar materials are used in innovative applications (such as using acrylic foam as a structural glazing adhesive), or as traditional materials continue to evolve. An example of the latter was the large number of papers presented on cement and concrete-related topics. This reflects the importance of these materials to the construction sector and the desire to extend or replace conventional Portland cement with a less CO2-intensive binder.
A common thread throughout many of the presentations was the need to couple information and communication technology tools with existing durability knowledge, both to manage the extent and complexity of the information and to provide a bridge between specialist information providers and users. This aligned with the theme of the BRANZ presentation – the durability assessment tool previously described in Build (see October/November 2007, page 68).
One ambitious example discussed was the CSTB’s ‘French National Service Life Information Platform’, which attempts to compile a database of reference service life declarations for generic building materials. It also includes a comprehensive empirical consideration of every variable that is likely to affect service life, allowing the platform to be used to make systematic assessments of durability even when reference conditions do not fully match the anticipated conditions of use. The creators hope that the database will bring together the experience of designers, observations from condition assessments, manufacturers’ performance declarations and data from auxiliary research. It will be interesting to see whether the reliability and extent of the contributed information will be sufficient to create a viable tool.
Other interesting topics in this area included examples using geographic information systems (GIS) to map the aggressiveness of the environment to which a building and its components are exposed and evaluate the risk of deterioration. The GIS data was linked to subsidiary tools of varying complexity. These ranged from a simple dose-response function for calculating rates of metallic corrosion as a function of salt deposition, to a Markovian-based building façade management model. The latter was intended to optimise maintenance planning and thus reduce both short- and long-term maintenance and rehabilitation costs.
Many attendees saw the potential for building information modelling to extend from a protocol for exchange of information between computer programs to a paradigm supporting knowledge-rich applications. These might include sustainability analysis methodologies such as LEED or BREEAM, energy performance declarations, service life prediction databases and checking designs against statutory requirements like building codes.
Moving from art to science
Durability assessment continues to slowly evolve from an art grounded in anecdotal evidence and personal experience, to a science based on predictive models verified by comprehensive databases of component service lives in well-characterised environments.
It is evident that, although the theoretical basis of service life planning is well understood and documented by the ISO 15686 suite of standards, much fundamental information is still needed to facilitate practical application. In particular, there remains a requirement for state-of-the-art accelerated laboratory test procedures and, especially, development of accurate correlations between those tests and service life data. BRANZ is actively working in this area and participates in several international committees addressing these challenges.
Articles are correct at the time of publication but may have since become outdated.