• Cracking and alkali silica reaction gel in concrete thin section.
  • 21st century suspension bridge with cast-in-place concrete.

Concrete Petrography

Our petrographers are experts in cementitious materials, construction technology, and the science behind concrete deterioration. Our laboratory is fully equipped for microscopy, chemical analysis, mechanical testing, and durability evaluations.

PPL photomicrograph showing undispersed silica fume in recently-place concrete
Expansive cracking in concrete from alkali-silica reaction (ASR) due to gravel aggregate
 

Petrography is an investigative method that uses polarized light microscopy to characterize and evaluate concrete materials, construction defects, and deterioration mechanisms. Petrographic examinations can be used for the following:

  • Confirmation of mix ingredients including supplementary cementitious materials

  • Estimation of mix water contents

  • Evaluation of entrained air structure

  • Identification of workmanship issues such as retempering or bleed water entrapment

  • Investigation of root causes of cracking

  • Evaluation of existing condition and assessment of serviceability

  • Determination of carbonation depth

  • Investigation of alkali-silica or alkali-carbonate reactivity

  • Evaluation of concrete decay due to sulfate attack or bicarbonation

All of our petrographers meet the qualifications of ASTM C856. While we engage in a broad range of petrographic studies, members of our team specialize in historical concrete and concrete exposed to aggressive service environments.

Our petrographers are skilled in the performance of ASTM C856, C295, and C457 for concrete, aggregate, and air-voids. Our full service chemistry lab supports concrete petrography through cement content determination and chloride analysis using ASTM C1084, C1152, and C1218. Where necessary, we supplement our studies with scanning electron microscopy, x-ray diffraction, Fourier transform infrared spectroscopy, and other instrumental analysis through our academic partnerships.