Speaker:

Chunyu (Joe) Qiao, PhD, PE – Senior Associate and Petrographer at Wiss, Janney, Elstner Associates

Presentation Title

Decryption of Concrete Quality and Durability Deterioration Mechanisms Using Concrete Petrography and Image Analysis

Speaker’S Bio

Chunyu Qiao is a Senior Associate and Petrographer at Wiss, Janney, Elstner Associates. He is an associate member of ACI Committees 201 (Concrete Durability) and 365 (Service Life Prediction). He is a junior editorial board member for Journal of Infrastructure Preservation and Resilience. Dr. Qiao received his PhD from University of Science and Technology Beijing, China. He was a visiting scholar at Purdue University from 2013 to 2015 and a postdoctoral researcher at Oregon State University from 2016 to 2018. His research interests include microscopy of cementitious materials, transport properties of cementitious materials, chemical admixtures, and concrete durability.

Abstract

While good workability and mechanical performance are critical for the concrete construction, the stakeholders also seek durable concrete that can last a desired service life without significant deterioration. Concrete durability comes in different forms of complex processes that commonly involve interactions between external substances (e.g., water, chloride, sulfate, etc.) and internal material properties (e.g., aggregate types, air-void system, paste components and microstructure). For instance, the absorbed water in concrete is essential for alkali-aggregate reaction to occur; water in concrete can cause freeze-thaw damage in cold weather regions. Concrete petrography, combined with image analysis and other techniques, provides a powerful tool to diagnose durability related concrete deteriorations. This presentation will provide a discussion of different projects that use concrete petrography and image analysis to investigate quality and durability mechanisms, such as concrete low strength issues, alkali-aggregate reaction etc.