Degradation of a 1928 precast concrete structure: thermal analysis as an investigative tool

摘要

An investigation of the underlying causes of deterioration of a precast concrete public building constructed in 1928. The present study uses thermal analytical techniques (DTA/ TGA) and X- ray Powder Diffraction (XRD) to examine the decay mechanism associated with the discoloration de-lamination of this recently restored structure. Water transport in porous bodies, the migration of soluble minerals and their deposition as precipitates is discussed. Permeability as a property of concrete is exan3ined as it relates to pH in hardened concrete and passivation of iron components. The ability of concrete to protect iron components from corrosion in a wet environment is largely determined by its permeability. The relationship between the products of concrete decay, the migration of those products and their re-deposition is discussed.