Developments in Performance Monitoring of Concrete Exposed to Extreme Environments

Abstract

The performance of the surface zone of concrete is acknowledged as a major factor governing the rate of deterioration of reinforced concrete structures because it provides the only barrier to the ingress of water containing dissolved ionic species such as chlorides, which ultimately initiate corrosion of the reinforcement. In situ monitoring of cover-zone concrete is therefore critical in attempting to make realistic predictions as to the in-service performance of the structure. To this end, this paper presents developments in a remote interrogation system to allow for continuous, real-time monitoring of the cover-zone concrete from an office setting. Use is made of a multi electrode array embedded within cover-zone concrete to acquire discretized electrical resistivity and temperature measurements, with both parameters monitored spatially and temporally. On-site instrumentation, which allows for the remote interrogation of concrete samples placed at a marine exposure site, is detailed together with data handling and processing procedures. Site measurements highlight the influence of temperature on electrical resistivity and an Arrhenius-based temperature correction protocol is developed using on-site measurements to standardize resistivity data to a reference temperature; this is an advancement over the use of laboratory-based procedures. The testing methodology and interrogation system represent a robust, low-cost, and high-value technique that could be deployed for intelligent monitoring of reinforced concrete structures.

Non-destructive measurement of chloride ions concentration in concrete – A comparative analysis of limitations and prospects

“…Specially, the splash zone near seawater, which is the area near the air/water interface, undergoes such deterioration, due to readily available atmospheric oxygen, water, and chloride [12][13][14]. On-demand maintenance of these structures not only preserves them but also reduces unnecessary costs and energy [15]. The chloride ion concentration in concrete is one of the most relevant parameters to estimate the risk of corrosion, and therefore predict the lifetime and maintenance cycle of RC structures [16][17][18][19].…”

Optimising the Performance of Cement-Based Batteries

“…There are a number of examples of ionic solution migration through hardened concrete. Chloride ions are considered to be the most dominant cause for corrosion of embedded reinforced steel in concrete [21,22] and can ingress through absorption, diffusion, wicking, and capillary action through an interconnected pore network. The process of corrosion of embedded steel in concrete is another example of ionic flow through set concrete.…”

Electrical Resistance to Monitor Carbonation and Chloride Ingress

“…Numerous sensors and monitoring systems have been developed to determine this property, such as the Anode Ladder (1), the Multi Ring Electrode (2) and the Covercrete Resistance Array (3). Due to the high sensitivity of electrical resistance to chemical and physical changes in pore structure of concrete, the electrical resistance is already used in structures to monitor the ingress of chloride ions (Cl -) in cover concrete (1)(2)(3)(4). Despite numerous practical applications of this approach, interpretation of electrical resistance data to assess accurately chloride profile or chloride content is still a challenge because of the high level of background noises from other factors, e.g.…”

“…Despite numerous practical applications of this approach, interpretation of electrical resistance data to assess accurately chloride profile or chloride content is still a challenge because of the high level of background noises from other factors, e.g. hydration, temperature and moisture content (4).…”