Spatial Variability of Concrete Properties within a Building Component

Concrete characteristics (e.g. diffusivity and critical chloride concentration)
exhibit a spatial variability due to the variability of batches and
workmanship during the construction of a structure but also due to the
variability in exposure. Therefore corrosion initiation and propagation
are spatially variable and thus the structural and serviceability
performance of the structure are influenced accordingly. Regular
inspections form an essential tool in condition control of concrete
structures. However there are a number of questions arising in terms of
the locations that should be inspected and the number of these
locations. This project aims to propose a framework to account for the
spatial variability phenomenon of the concrete properties. A random
field approach is introduced to enable the modelling of the random
spatial variability of concrete material characteristics. A framework
is proposed for defining the number of measurements that can
sufficiently represent a structure and at which locations should the
measurements be taken. Within this framework the associated
uncertainties, basically those of a physical nature, can be reduced.
Furthermore it is examined how the statistical uncertainties associated
with the structure's assessment can be taken into account. The proposed
framework enables further the definition of acceptance criteria
according to the owner's needs regarding the inspection time, the
percentage of the structure that should be inspected and the extent of
a certain condition that is acceptable. For the purposes of this
project real data are to be used.

• Spatial Variability of Concrete Properties within a Building Component (ETH Research Database 10828)