Background and Introduction

This massive concrete infrastructure deterioration problem calls for a radical change of the current limit state design philosophy which is concerned mainly with the safety and serviceability of newly-built concrete structures to the design and management of performance of concrete structures over their entire life span, a technology that is commonly referred to as “Life-Cycle Management (LCM)”. The implementation requires not only the accurate prediction of the chronic performance degradation of concrete infrastructures but also the development of advanced maintenance and intervention methods to timely upgrade the performance wherein necessary. Appropriate performance management can extend the design service life of existing concrete infrastructures, while without appropirate maintenance the performance may be deteriorated at early stage due to severe mechanical and environmental loadings possessing the risk of reduced service life (Fig.1). In addition, in order to achieve the designed service life of concrete infrastructures, different maintenance strategies (Fig.2) can be used and an optimal solution is expected to be found, for instance, based on the minimum life cycle cost (LCC) concept.

Fig.1. Performance degradation & maintenance vs. service life

Prof Dai’s research focuses on the development and use of innovative materials and structural systems for effective life cycle performance maintenance and improved sustainability of concrete infrastructures. The main activities include: (1) use and development of high performance reinforcement (e.g., fiber-reinforced polymer composites) and cementitious materials (e.g., ultra-high performance concrete and engineered cementitious composites) for minimizing the maintenance need (Fig. 2a); (2) use and development of advanced surface treatment technologies for realizing preventive maintenance (Fig. 2b); (3) use and development of advanced performance monitoring and assessment tools for realizing predictive maintenance (Fig.2c); and (4) use and development of advanced repair and strengthening technologies for corrective maintenance purpose. Overall, Prof Dai's group aims to achieve sustainable concrete infrastructures based on a holistic consideration of the service environments and loadings, materials usages, detailed designs, construction, performance monitoring and assessment, repair and strengthening as well as the life-end strategies of concrete infrastructures (Fig.3).

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Fig.2. Different maintenance strategies for the LCM technology

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Fig.3. LCM technology for improved sustainability of concrete infrastructures

Research Topics in Detail