Research & Development
Resistivity of polymer modified repair mortars and its impact on the performance of electrochemical protection systems
The suitability of polymer modified repair mortars used for electrochemical repair systems is based on 28-day resistivity data under saturated conditions. It is commonly assumed that such resistivity data is indicative of a material’s long-term resistivity performance under service conditions. A major research program is currently being undertaken by Remedial Technology into the resistivity performance of various ‘low resistivity’ concrete repair mortars in saturated and outdoor exposure conditions over extended periods of time.
The impact of concrete resistivity on the design of cathodic protection systems is noted in all global concrete cathodic protection standards including Australian Standard AS 2832.5 – 2008 (R2018) and is a key design consideration. However, none of the standards include specific, relevant guidelines related to the consideration of resistivity data in the design process for cathodic protection systems.
The importance of this research work is to assess the impact of the long-term resistivity of the polymer modified mortars identified as ‘low resistivity mortars’ in the Australian market on the performance of ICCP and SACP systems.
The outputs from this research work have been progressively implemented in the material selection for galvanic anode and ICCP system designs by Remedial Technology. Remedial Technology is currently involved in the testing of new polymer modified mortars to assess their suitability for use with ICCP and galvanic anode systems. The laboratory and outdoor testing for the new mortar materials is being performed in accordance to AASHTO T358-19 Standard.
Prevention of grout acidification for impressed current cathodic protection systems in tidal and splash zones
The acidification of grout material around anodes has been identified as one of the major problems for ICCP systems operating in tidal and splash zones. Poor anode embedment detail, often combined with inadequate quality control and workmanship during construction can allow water ingress to the anode and this can result in localised grout acidification (deterioration and failure of the grout material). This defect can cause current dumping and loss of grout impacting on the current delivery of the ICCP system.
Remedial Technology has conducted significant research work over several years into this problem and has developed various encapsulation details to prevent the occurrence of this problem in ICCP applications operating in tidal and splash zones.
Remedial Technology’s new details for grout acidification have been successfully implemented for various marine structures in NSW and Queensland and are being incorporated into the designs for new ICCP systems being installed in tidal and splash zones.
Pictured: Ephraim Island Bridge, Gold Coast (top), Ulladulla Jetty (middle) and Coila Creek bridge (bottom)