What's This Report For? Part 4: Special Inspection and Petrographic Reports-The Petrographic Report-What the designer needs to know (PDF)

The Petrographic Report-What the designer needs to know (PDF)

Pdf Summary

The article "The Petrographic Report: What the Designer Needs to Know" by Richard D. Stehly and Adam J. Brewer emphasizes the complexity and critical role of petrographic reports in the concrete industry. These reports, which often arise when concrete performs unexpectedly, are complex and carry significant weight—especially within litigation contexts. Petrography differs from simpler testing methods as it utilizes a suite of techniques, primarily optical microscopy, and requires professional judgment for accurate analysis and reporting.<br /><br />Petrographic studies are generally reserved for problem-solving due to their time and cost demands, often exceeding routine testing budgets. The American Society for Testing and Materials (ASTM) C856 outlines standard practices, enabling petrographers to choose techniques appropriate to the questions posed. They analyze aggregates, the air-void system, cement paste quality, and more to identify concrete issues such as spalling and cracking.<br /><br />The article further discusses the qualifications for a petrographer, highlighting the necessity of geology education, field experience, and the ability to make informed judgments. Moreover, individuals commissioning petrographic reports are urged to provide comprehensive context on the concrete sample, including photographs, project history, and detailed observations.<br /><br />Sampling techniques are crucial; samples need to be representative and sufficiently large to capture the problem and remain intact through shipment. Once delivered to the laboratory, petrographic studies can integrate with other testing forms to provide comprehensive diagnostic insights.<br /><br />Overall, the report serves as an educational tool for understanding the critical information contained within petrographic reports and stresses effective communication and sampling strategy to maximize the report's utility. These can guide in addressing concrete-related issues promptly and effectively.

Keywords

petrographic reports

concrete industry

optical microscopy

ASTM C856

aggregate analysis

cement paste quality

spalling

cracking

geology education

sampling techniques