- Author
-
Clifton, J. R.
|
Pommersheim, J. M.
- Title
- Methods for Predicting Remaining Life of Concrete in Structures.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
Bucknell Univ., Lewisburg, PA
- Report
-
NISTIR 4954,
November 1992,
30 p.
- Distribution
- Available from National Technical Information Service
- Keywords
-
concretes
|
structures
|
building technology
|
corrosion
|
diffusion
|
service life
|
reinforcement
|
reaction controlled
|
remaining service life
|
time order
- Abstract
- The ability to predict the remaining life of concrete structures is becoming increasingly important as the nation's infrastructure ages. Decisions on whether to repair or to demolish structures may depend on the estimated remaining life. Little attention has been given to developing methods for predicting remaining service lives, with most of the reported work dealing with corrosion of concrete reinforcement. These methods primarily involve the use of mathematical models and life-time extrapolations based on corrosion current measurements. Predicting remaining service life usually involves making some type of time extrapolation from the present state of the concrete to the end-of-life state. The application of the time order concept in making time extrapolations is described in this report. Also, ways to determine the value of n (time order) in the time function t. of degradation rate relationships are given. Use of the time order approach is demonstrated for n = 1/2, 1, and 2. Ways to aply the approach to cyclic processes and multi-degradaton processes are also discussed. Situations may be encountered in which the remaining servicelife of concrete can only be estimated by predicting its original life using a service-life model. Such a situation could arise where the concrete can not be inspected or samples taken, due to its inaccessibility or to potential serious hazards involved with its inspection. An approach for applying this method is discussed.