Dr. Harris specializes in concrete and other cementitious materials. He has experience investigating durability and performance issues related to concrete ingredients, concrete building components, concrete pavements, portland cement-based plaster (stucco), fire-damaged concrete, cementitious toppings, tile, asbestos-cement pipe, and concrete surface coatings. He has experience analyzing the physical and chemical properties of concrete’s cementitious constituents particularly those properties that influence concrete durability. He also has experience investigating water intrusion and moisture accumulation in building components such as decks and roof assemblies.
Dr. Harris’ educational background includes coursework in engineering materials, mechanics of materials, design of steel, concrete and timber structures, and finite element analysis. His coursework also included minors in geotechnical engineering and engineering management. He has experience in the analysis of concrete and cementitious materials through the use of optical and scanning electron microscopes. He also has experience in the development and operation of finite element analysis pre-processing software.
Prior to joining Exponent, Dr. Harris was a researcher at Cornell University where he studied the use of supplementary cementitious materials in portland cement concrete. His research focused on the interactions between chemical admixtures and fresh concrete paste and their influences on concrete air void systems and freezing and thawing durability. Another primary focus of Dr. Harris’ research was on methods for testing and control of supplementary cementitious materials for use in concrete.
Ley MT, Harris NJ, Folliard KJ, Hover KC. Investigation of air-entraining admixture dosage in fly ash concrete. ACI Mat J 2008, 105(5):494–498, September/October.
Harris NJ, Kover KC, Folliard KJ, Ley MT. The use of the foam index test to predict AEA dosage in concrete containing fly Ash: Part I—Evaluation of the state of practice. J ASTM Int 2008; 5(7), July.
Harris NJ, Kover KC, Folliard KJ, Ley MT. The use of the foam index test to predict AEA dosage in concrete containing fly ash: Part II—Development of a standard test method: apparatus and procedure. J ASTM Int 2008; 5(7), July.
Harris NJ, Kover KC, Folliard KJ, Ley MT. The use of the foam index test to predict AEA dosage in concrete containing fly ash: Part III—Development of a standard test method: proportions of Materials. J ASTM Int 2008; 5(7), July.
Harris NJ. Evaluating the influence of fly ash on air entrained concrete. Doctoral Dissertation, Civil Infrastructure, School of Civil and Environmental Engineering, Cornell University, Summer 2007.
Harris NJ, Hover KC, Folliard KJ, Ley T. Variables affecting the ASTM Standard C 311 loss on ignition test for fly ash. Journal of ASTM International 2006; 3(8), September.
Benzley SE, Harris NJ, Scott M, Borden M, Owen SJ. Conformal refinement and coarsening of unstructured hexahedral meshes. Journal of Computing and Information Science in Engineering 2005; 5(4):330-337, December.
Harris NJ, Benzley SE, Owen SJ. Conformal refinement of all-hexahedral finite element meshes based on multiple twist plane insertion. Proceedings, 13th International Meshing Roundtable, pp. 157-167, Williamsburg, VA, September 2004.