April 4, 2008, 2:00 p.m., Holmes Hall 244
Material Health Monitoring of Concrete:
A Vital Component of Sustainable Infrastructure Development
Department of Civil and Environmental Engineering
University of Hawai`i at Manoa
Traditional methods of design and construction of engineering infrastructure have not been sustainable. Many of the existing structures (e.g., bridges, roads, piers, etc.) are deteriorating at an alarming rate and requiring significant repair or replacement. As the nation begins rehabilitating its infrastructure, it is important to improve the durability and life-expectancy of new and existing structures to reduce their need for future maintenance and repair. The new structures must be built using high performance materials with better durability, smaller energy and carbon foot-print, and by incorporating higher quantities of recycled materials. To achieve superior structural durability, it is essential to accurately monitor the health and condition of a structure as it ages. Health monitoring enables engineers to take preventative measures to avoid premature damage development and to enhance the remaining life and performance of the structure.
This presentation describes the development of a non-destructive sensing and health monitoring system that is designed for in-situ assessment of the durability performance of concrete structures. The sensing system is composed of three electrical conductivity-based sensors that measure the most important material properties of concrete throughout its service life. Application of these sensors enables: 1) continuous examination of the meso-structure and damage development in concrete, 2) in-situ evaluation of the material’s transport properties (including hydraulic permeability and ion diffusivity), 3) constant composition monitoring of concrete’s pore solution (to evaluate the risk of corrosion, chemical attack, and alkali-silica reaction), and 4) accurate measurement of the material’s internal humidity and moisture content (to evaluate its shrinkage behavior and freeze/thaw performance). In addition to providing accurate and non-destructive condition assessments, measurements from these sensors can be fed into transport simulation models to predict and optimize the life-cycle cost and performance of concrete structures.