Sustainable management of concrete structures
The challenge
Well-known damage mechanisms for concrete structures are alkaline-silica reactions and reinforcement corrosion. They affect both the safety and functionality of concrete structures. There is currently insufficient knowledge about the degradation mechanism, and we cannot easily estimate maintenance requirements. We are therefore unable to effectively and efficiently manage and improve the life cycle of concrete structures. This calls for a strategy, so that tests can be carried out any time in the lifespan to determine whether a concrete structure satisfies the quality requirements stipulated in the design phase.
The interest
This issue is of great interest for the world of concrete, the construction companies, as well as for large principals such as the Department of Transport, Public Works and Water Management. Life cycle management is becoming increasingly important because we know that sustainable construction and maintenance is extremely significant for managing and forecasting costs, and for improved planning of maintenance and (re)construction.
The results
Within the project ‘Sustainable Management of Concrete Structures’, we are developing the tools needed for such a strategy. This involves models to forecast the lifespan, methods for measuring the quality of the structure, and repair and preventative strategies for reinforced and pre-stressed concrete structures.
The project is divided into five work packages. The work packages are aimed at the following end products:
Product of knowledge
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What is it?
State- of-the-art manual covering foundations, modellling, monitoring, and strategy for low-maintenance infrastructure.
What can we use this for?
There is a considerable need for improvements in the construction and management of concrete structures. Many construction works in and along the Dutch road system date from just after the Second World War and are reaching the end of their life expectancy. At the same time, a longer life expectancy is explicitly required for many large infrastructural works than was originally assumed in the construction specifications, and society is demanding more stringent requirements regarding (the costs of) availability, comfort and environmental impact. A new manual will be published at the beginning of 2010 that includes the latest insight into life expectancy design and lifetime management of concrete structures. The objective of this manual is to show all those involved the advantages of cost-optimal management for concrete structures throughout the entire lifecycle, and to facilitate an objective and rational approach to the life expectancy problems of concrete structures. With this overview, the reader has:
• Insight into the processes that damage concrete.
• Improved forecasting models
• Guidelines for sound management in order to trace undesirable phenomena in a timely way.
• Clear criteria during implementation.
• Guidelines for establishing a maintenance plan based on forecasting models.
• Insight into monitoring strategies.
• Insight into special repair materials and preventative techniques.
• Insight into problems that arise when combining old and new concrete (for example, when carrying out repairs).
Who will be interested?
Department of Transport, Public Works and Water Management, managers, builders in the soil, roads and hydraulics sector, engineering consultants.
More information
k.vanbreugel@tudelft.nl
rob.polder@tno.nl
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• WP1 Degradation Mechanisms: degradation models as a basis for performance criteria
More information:
Transport of moisture and harmful species
ASR-induced expansive gel formation and crack propagation
Frost salt scaling of cement based materials with a high slag content
Determination of time dependent chloride diffusion coefficients in concrete by modeling of realistic situations
• WP2 Initial State: tools to determine the performance of a structure when delivered
More information:
Reliability of prediction of stresses and probability of cracking in hardening concrete
• WP3 Condition Assessment and Monitoring: methods for measuring conditions and monitoring strategies
More information:
Technical integration and interpretation of monitoring results for maintenance management
Structural condition and safety at a reduced concrete tensile strength
• WP4 Maintenance and Repair: sustainable repair and maintenance strategies
More information:
Interfaces of concrete repair
Durability of surface repair and protection systems
Influence of chemical spray sealing on the durability of HSC
• WP5 Performance Based Management: performance-oriented maintenance framework for reinforced and pre-stressed concrete.
More information:
Performance based management of reinforced structures
Performance based management of prestressed structures
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