1 Petrology
Wednesday, 11 April 2007
10:00 AM - 12:00 PM
THE USE OF FOSSILS AND MINERAL SPECIFICITY IN FORENSIC CONCRETE PETROGRAPHY
Paper number: 1-6
Program: Technical Sessions
Time: 10:40 AM – 11:00 AM
Authors
Abstract
Forensic petrography has also helped solve investigations concerning the loss of airfreight shipments from around the world. The shipped goods and items such as computers taken from cargo containers were intercepted and replaced with rocks or various materials such as concrete, aggregates, or fabricated items such as brick pavers or concrete masonry units (CMU). Several cases have been solved using index fossils and specific mineral types to identify likely locations where the goods were stolen. The aggregates used in these replacement items were identified as being from specific local sources using the fossils in the limestone aggregates and associated mineral species unique to that area. Mineral specificity and fossils provide a good means to identify the source of concretes that have short-term performance problems such as alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR). In addition, the petrography of sands used in historical mortars for preservation of historical courthouses, US Post Offices and other federal buildings have proven helpful in identifying likely sources for the original masonry sands or native stones used on the building.