STTR Phase I: Protection of Rebar in Construction Materials using Tobacco Extract Corrosion Inhibitors

Inhibitrol Inc, Parkton MD

Investigators

Abstract

This Small Business Technology Transfer (STTR) Phase I project will develop tobacco as an additive to concrete and other construction materials to reduce corrosion of rebar. Degradation of bridge decks and other reinforced concrete structures is predominately caused by the corrosion of the rebar, which expands and leads to cracking or spalling of the concrete surface. The corrosion of rebar is most often associated with road salt or marine environments that provide a source of chloride ions that promote corrosion. Previous studies have shown that extracts of tobacco are an extremely effective, environmentally benign corrosion inhibitor for many metals, including steel and aluminum, under a variety of conditions (chloride solutions, acidic, neutral, and alkaline environments). Inhibitrol proposes to add tobacco dust or other tobacco material to concrete and other building/patching materials. As salty water penetrates the concrete, it will leach corrosion inhibitors from the tobacco and protect the steel rebar. The current corrosion inhibitor additives used to protect the steel rebar are expensive and may cause environmental concerns. Tobacco is a renewable, potentially inexpensive bioproduct that is expected to provide excellent corrosion protection with few or no environmental concerns. A recent report on the costs of corrosion estimates that the annual cost of corrosion of infrastructure is $22.6 billion with $8.3 billion being attributed to bridges. Indirect costs of bridge corrosion (traffic delays and lost productivity) are estimated to be ten times the direct costs. Tobacco-based corrosion inhibitors for concrete would have several benefits: a reduction in required maintenance and improvement in capacity and safety of bridges and other structures, substitution of a renewable bioproduct for petrochemical-based chemicals, and reduced environmental impact. The Inhibitrol team will work closely with professors and students at the Small Farm Institute of the University of Maryland Eastern Shore (UMES), a Historically Black (HBCU) Land Grant Institution, to identify the best tobacco strain and farming practice for this application. In addition to the potential benefits associated with protection of infrastructure, this application may open new markets for tobacco farmers and find uses for their waste products.