Measuring resistivity as a method to calculate formation factor is becoming a popular way to evaluate transport properties of concrete. Resistivity measurements are dependent on multiple factors including the resistivity of the pore solution, leaching effects, the degree of saturation of the specimen, the age of the specimen (degree of...
The corrosion resistances of several alloys were investigated to optimize performance and cost in seawater and supercritical CO2 environments. Many alloys are prone to corrosion in seawater and/or supercritical CO2 containing impurity environments. Exposure and electrochemical experiments were conducted in both environments to evaluate alloys’ corrosion resistance. In seawater corrosion...
Interest in performance specifications has been growing in the civil and construction industry in the past decade. One major focus area has been on understanding how to prolong the service life of concrete structures, since repair and rehabilitation of existing infrastructure have cost many trillions of dollars. Deterioration mechanisms such...
Chloride-induced corrosion is one of the primary causes of the degradation of reinforced steel in concrete structures. Currently, the rapid chloride permeability test (RCPT) is the most specified method to determine the concrete’s resistivity to chloride ingress, thus a determining factor in assessing the durability of concrete. While it is...
The constituent materials of concrete often contain chlorides. The presence of chlorides in sufficient amounts can disrupt the passive layer, also known as the passive film, that protects the reinforcing steel in concrete. This disruption can lead to premature corrosion of the reinforcing steel in concrete. To minimize the risk...
High early strength (HES) concrete is becoming increasingly used to repair damaged concrete pavement sections. The use of HES concrete enables the repaired pavement to be opened to traffic within hours of placing the concrete. A common approach used for the rapid repair of concrete pavement consists of closing a...
Carbon steel, which contains mostly iron, has been widely used as reinforcement in reinforced concrete. In the alkaline environment in reinforced concrete, a thin iron oxide film, called the passive film, forms on the surface of the steel, which protects the surface from active corrosion. The exact atomic structure of...
The goal of the first part of this project was to investigate the influence of aggregate source and entrained air on the transport properties of concrete. Currently, there are several ASTM standards available that provide systematic procedures to evaluate mass transport properties of concrete. ASTM C642-13 (ASTM 2013), often referred...
The issue of chloride-induced corrosion of reinforcing steel in concrete and its economic impacts are well-known. Chlorides that cause reinforcement corrosion can be from constituent materials used to prepare concrete or can enter the hardened concrete when the structure is exposed to chloride environments. To minimize the risk of reinforcement...
A Cu/Fe-spinel-based oxygen carrier designed at the National Energy Technology Laboratory was studied in order to characterize its physical and chemical behavior with cyclic oxidation and reduction treatments at 800°C for applications in chemical looping combustions. Observations were made on individual particles of the oxygen carrier in-situ using a confocal...