Petrography

Located in Boulder, CO, Twining owns and operates one of the nation’s premier concrete petrographic analysis laboratories. This laboratory uses analytical methods to investigate concrete and other cement-based construction materials, natural rock products, and geological resources.

We routinely perform petrographic analysis of aggregates in accordance with ASTM C295, petrographic analysis of hardened concrete and other cement-based construction materials in accordance with ASTM C856, air void analysis in conformance with ASTM C457, analysis of mortar in accordance with ASTM C1324, and uses SEM/EDX methods as described in ASTM C1723.

Our senior principal petrographer, David Rothstein, PhD, PG, FACI, is recognized nationally as a leader in petrographic analysis of aggregates, concrete, and other cement-based construction materials. Dr. Rothstein has more than 20 years of professional experience in petrographic analysis. He has performed more than 1,500 petrographic investigations on more than 8,500 samples of construction materials from projects throughout the United States from Alabama, Alaska and Arizona to Wisconsin, and Wyoming, Hawaii as well as Puerto Rico. International engagements include the Bahamas, Canada, China, Colombia, Costa Rica, Diego Garcia, Dominican Republic, Mexico, Mauritius, Panamá, Philippines and Thailand.

Our investigations have focused on issues and construction challenges that range from placement and finishing to durability related deterioration mechanisms such as freeze-thaw damage and alkalisilica reaction (ASR). We have extensive experience with a wide variety of early-age problems associated with placement, finishing and curing on pavements as well as durability mechanism related to chemical attack (including sulfate attack), corrosion, marine attack, and salt weathering. We have also performed hundreds of aggregate analyses on high profile construction projects.