Tolerance limit of chloride for steel in blended cement mortar using the cyclic polarisation technique

Abstract

The tolerance limit for chloride in ordinary Portland cement (OPC) and blended cements such as Portland pozzolana cement (PPC) and Portland slag cement (PSC) was assessed by cyclic polarisation. This study covers both cement extracts and mortar. The salient features of this investigation were: in extracts, the tolerance limit for chloride actually doubles for PSC when compared to PPC and OPC. The tolerance limit for chloride for various mortars follows the order: PSC [ PPC [ OPC. In OPC and PPC mortar, the repassivation potential (E rep ) shifted negatively with higher amounts of free chloride but in PSC mortar E rep shifted positively (+590 mV) even in the presence of 5,000 ppm of free chloride. PSC takes longer time (50 days) to reach E rep indicating perfect passivity maintained for the embedded steel.

Evaluating the Ph Sensitivity of Carbon Nanotube-Polyaniline Thin Films With Different Dopants

“…1 While this glass electrode works well and o®ers accurate pH measurements in the laboratory, it is fragile and cumbersome to use in many applications such as monitoring the pH of soil or that of human blood levels. 2,3 Thus, other types of pH sensors are needed for providing accurate and robust measurements of pH in complex operating conditions. Di®erent types of pH sensors such as semiconducting metal oxides, ion-selective¯eld-e®ective transistors, micro-electromechanical systems, and organic thin¯lm transistors have shown to be good alternatives to ISEs but may require complex fabrication techniques and can su®er from high costs.…”

Solid Potential Reference Electrode for Concrete Corrosion Monitoring

“…1), with its potential between the potentials of the two semireactions of reduction (1) and oxidation (2).…”

“…(1) The measurement of the potential of the reinforcement steel based on reference electrodes and potentiometers of high internal impedance, or measurement of the mixed potential of corrosion, is one of the most simple techniques to apply and also one of the most widely used. (2) Figure 1 shows a schematic representation of the reinforcement iron corrosion process using the Evans diagrams. These diagrams are very useful in the analysis of electrochemical phenomena such as corrosion and, as we shall see later, the phenomena that develop in the electrodes studied in this work.…”

Consideration on the Risk of Corrosion Assessment in Reinforced Concrete Structure by Corrosion Potential Criterion

“…부식전위 (corrosion potential) 측정법은 콘크리트 속 에 있는 철근의 부식상태를 전위측정으로 진단하는 방법으 로 보통 자연전위 (half-cell potential) 측정법이라고도 한 다. 이 방법은 토목 및 건축 관련 산업에 종사하는 엔지니어 들에게 보편적으로 가장 널리 사용되고 있는 진단법이다 3) . 측정된 부식전위 데이터는 콘크리트 구조물의 보수, 보강, 품질 보증 및 내구수명을 예측하는 자료로 사용된다.…”