Title:
Assessment of Damage Gradients Using Dynamic Modulus of Thin Concrete Disks
Author(s):
Ufuk Dilek
Publication:
Materials Journal
Volume:
105
Issue:
5
Appears on pages(s):
429-437
Keywords:
damage assessment; damage gradients; durability; nondestructive evaluation
DOI:
10.14359/19971
Date:
9/1/2008
Abstract:
Thin circular disks sawn from cylinders or cores are widely used in the measurement of chloride or air permeability of concrete and water-soluble chloride penetration into concrete. Whereas these methods provide useful information on concrete properties with depth, the capability of measuring changes in mechanical properties in small-depth increments is of value to both researchers and consulting engineers practicing in condition assessment. This study presents applications of testing the dynamic Young’s modulus of thin disks to structural assessment projects involving damage gradients. Three different damage mechanisms are discussed: exposure to fire, freezing-and-thawing damage, and exposure to rain following placement. The use of thin disks enabled determination of mechanical properties of relatively thin layers of concrete and, therefore, provided a means to quantitatively assess the extent of damage gradients. Thin disks presented an advantage over the compressive strength of cores, which represent a larger depth of concrete, in cases involving relatively thin layers of damage.