Petrographic Studies

Petrographic Studies

Petrography involves the identification, systematic description and geological classification of rocks. The three principal rock groups, i.e. igneous, sedimentary and metamorphic, may all be examined and classified by petrological techniques. These techniques can be similarly used to provide valuable information concerning the characteristic minerals and structures occurring within the concrete. Microscopic analysis permits observations on: Aggregate, cement type, cement content, water/Cement ratio, carbonation, cracking, porosity, permeability and predicted performance.

Concrete can suffer from a variety of problems for which petrography can be usefully employed in diagnosis e.g.

• Alkali-Aggregate reactivity
• Shrinkable aggregates
• Frost susceptible aggregates
• Sulphate attack
• Reinforcement corrosion
• Drying shrinkage
• Leaching