ASTM C876 Research Articles

Application of Electrochemical Method to Evaluate the Corrosion Conditions of Steel Bars

The purpose of this research is to use an electrochemical method to evaluate corrosion conditions of steel bars in concrete. According to the description of ASTM C876, when the corrosion potential measurement values of the steel bar are below -350 mV, there may be a greater than 90 percent chance of corrosion. If the current impedance of the concrete is below 10 kΩ-cm, there is a possibility of corrosion in the steel bar. The test plan is as follows: to use concrete with different concentrations of chloride ions or applying an electric current to the steel bars to accelerate the corrosion reaction. In addition, we plan to use a solution of chloride ions to simulate sea tidal erosion on reinforced concrete structures by spraying. According to the experimental observations, concrete containing chloride ions is very likely to cause internal corrosion of the steel bar. The current impedance of the concrete can be used as the basis for assessing the internal humidity and moisture content of concrete. With an increase in curing time, the concrete's resistance correspondingly increases.

Long-term reinforcement corrosion in low carbon concrete with a high volume of SCMs exposed to NaCl solutions and field marine environment

Chloride-induced corrosion in low carbon concrete with a high volume of SCMs exposed to (i) accelerated corrosion by impressed current, (ii) 9-year NaCl-simulated tidal condition and (iii) 5-year field marine tidal condition was compared in this study. The effectiveness of different exposure conditions and indicators in distinguishing the parameters affecting the corrosion resistance of concrete was investigated. The results showed that at a high w/b ratio of 0.6, the accelerated corrosion test provided inconsistent ranking for the corrosion resistance of binders when continuous and intermittent impressed voltage were applied. At a w/b ratio of 0.4, the electrochemical measurements from both accelerated corrosion and laboratory-simulated tidal exposure confirmed the advantage of 30 % FA blended cement concrete in protecting reinforcement, whereas results from two exposure conditions denoted opposite ranking for the corrosion resistance of GP cement and 50 % slag blended cement concrete. The statistical analysis of the 674 independent data points (Ecorr, Rp) suggested that using −465 mVSCE as the upper limit for indicating a higher than 90 % corrosion probability was more reliable than the −350 mVSCE from ASTM C876. Compared to field marine tidal exposure, long-term wet/dry cycles in 3 % NaCl induced faster corrosion initiation and propagation, thereby higher weight loss of reinforcement. The chloride contents permitting corrosion initiation were higher for concrete with more binder due to a higher alkalinity. The complex interaction between chloride, alkalis and reinforcement corrosion leads to difficulty in discriminating the corrosion resistance of various binders, especially in long-term exposure.

Effect of corrosion inhibitor on service life of cracked and non-cracked concrete

Corrosion of steel in reinforced concrete structures can cause damage and costs involved and attracts researchers to look for solutions that delay the onset of corrosion initiation or slow its development. The effectiveness of four corrosion inhibitors in cracked and non-cracked sections of reinforced concrete was studied: Migrating Corrosion Inhibitor (MCI-2005) based on amine carboxylate; CNCI 1.37 based on calcium nitrite Ca (NO)2 at a concentration of at least 30%; and two lab-made green corrosion inhibitors based on recycled materials – fluorosilicates obtained from fluorosilicic acid (H2SiF6), the by-product of the phosphate industry, and from LABS (Linear Alkyle Benzene Sulphonate), the by-product of the detergent industry. The study followed the guidelines of the ASTM G-109 standard which examines materials intended to inhibit chloride-induced corrosion of steel in concrete, and the ASTM C-876 standard which evaluates the electrical corrosion potential of uncoated reinforcing steel, for the purpose of determining the corrosion activity of the reinforcing steel. Controlled artificial cracks of different depth were created to speed up the corrosion process in the steel. Such cracks allowed a direct penetration of chlorides into the depth of concrete. As was expected, the cracked concrete samples exhibited a significantly higher level of corrosion than the non-cracked samples. In the non-cracked samples, the effectiveness of the CNCI 1.37 commercial corrosion inhibitor was the highest. However, in the cracked samples it appears that its efficiency has decreased, while the recycled corrosion inhibitor based on K2SiF6 has shown the best performance. This result can be explained by the fact that fluorosilicate reacts with calcium hydroxide present in concrete and creates a non-permeable protective layer that inhibits the movement of chlorides to the steel bar.

Inspection of Steel Bars Corrosion in Reinforced Concrete Structures by Nondestructive Ground Penetrating Radar

In this study, the degree of corrosion of steel reinforcement is compared to the reflected voltage of electromagnetic waves and the ASTM C876 specification. This study conducted some tests on steel bars with different degrees of corrosion by transmitting electromagnetic waves in the reinforced concrete. In the test, a corrosion potentiometer was used to analyze and compare the experimental results. The electromagnetic wave reflection signals from the image generated by the ground penetrating radar were used to capture the different media in the concrete components. The reflection coefficient method was used to analyze the calculated relative dielectric constant of the media and to obtain the reflection energy and phase changes on the medium interface. We compared and discussed the corrosion potential and the reflected voltage from the corroded steel bars in the reinforced concrete. The reflected voltage analysis of the ground penetrating radar showed that the average corrosion potential on the corroded plate on the 3rd floor was −280 m V (Area C). According to ASTM C876, the steel bars in the concrete were moderately corroded. The reflected voltage analysis of the electromagnetic waves concluded that areas A and B were moderately corroded, which is consistent with the conclusion from ASTM C876. Using the innovative method, this study has established a reference standard for the degree of corrosion of steel bars based on ASTM C876 and has calculated the quantitative state of corroded steel bars. The variations of the electromagnetic wave reflected voltage of the ground penetrating radar can mark the changes in the corrosion interface of concrete and steel reinforcement with different degrees of corrosion and different thicknesses of the protective layer.

Improving half-cell potential survey through computational inverse analysis for quantitative corrosion profiling

Corrosion of reinforcing steel is the primary cause of reinforced concrete (RC) premature failure. Half-cell potential survey based on ASTM C876 is a widely-used method to evaluate RC corrosion. However, the quality of the survey depends on the amount of data acquired, and data acquisition translates into labor time. Low quality surveys may lead to poor evaluation and misleading assessment. This study demonstrates that field survey augmented with computational methods is a promising approach to an improved diagnosis of RC corrosion. The approach augments field data from half-cell potential survey with computational method to diagnose the location and size of corrosion in the reinforcing steel of RC. The computational method integrates Particle Swarm Optimization into Boundary Element Method to carry out inverse analysis. The effectiveness of the approach was tested for an RC column of a local building affected by the 2004 Indian Ocean tsunami. The half-cell potential survey was used to find the general location of the corrosion in the RC. The computational inverse analysis was then used to diagnose the location and size of the corrosion based on the acquired field data. The actual corrosion location and size were then confirmed by breaking up the RC column. It was found that the approach was able to diagnose the location and size of corrosion up to 95.65% of accuracy. This study concludes that computational inverse analysis is a promising venture to improve the quality of and extend the usability of the half-cell potential survey for quantitative corrosion profiling.

Simulation of corrosion field measurement on reinforced concrete using BEM

Reinforced concrete (RC) corrosion is a leading of structural deterioration and premature degradation for the infrasturctures, with significant affected for safety, durability and reability. Therefore, early assessment of RC corrosion is important to prevent deterioration of the structure. The objective of this paper is to apply Boundary Element Method (BEM) for improving reinforced concrete (RC) corrosion assessment using field measurement data. In this study, the potential on whole domain of concrete structures was modeled by Laplace equation. The Laplace equation was solved by BEM, hence the potential on the concrete structure can be determined. The field data were measured by using half-cell potential technique and collected from an existing house in Aceh region that struck by the 2004 Sumatra tsunami. The simulation results show the use of BEM can improve the RC corrosion assessment. According to ASTM C876, the distribution of potential values on the concrete surface above the corroded area were in range -200 mV to -350 mV that indicated active corrosion was occurred. It can be inferred, the method can improve the field measurement data since it has capability to predict the corrosion profiles of reinforcing steel in more precise.

Use of Cedrela odorata Linnaeus Exudate for Inhibiting Corrosion by Chlorides in Reinforced Concrete

This paper evaluates the use of cedar tree exudate in chloride penetration and the probability of steel corrosion in reinforced concrete (rc), considering 0.3, 0.5, 0.7, and 0.9 % exudate by cement weight in the mixture at water/cement (w/c) ratios of 0.55 and 0.60. Under these conditions, cylindrical specimens of 4 inches in diameter and 8 inches in height were constructed. The water-sol- uble chloride content of the extracted concrete powder was measured at 0.5, 1.0, and 2.0 cm depth according to astm C1218/C1218M, while the probability of corrosion was determined by measuring electric potentials with astm C876. A favorable incidence of 0.46 % by weight of concrete was found when using 0.7 % exudate at the w/c ratio of 0.55 at the closest depth to the steel, compared to the 0.55 % target. The probability of steel corrosion is reduced to 10 % with potentials higher than -0.2 V with more prolonged exposure to chlorides.

Experimental Study on Anode Life and Effective Distance of Sacrificial Cathodic Protection in Reinforced Concrete

The purposes of this study were to examine influences of concrete quality and environmental severity on anode life and to determine effective distance of sacrificial cathodic protection in reinforced concrete. 100 x 100 x 400 mm3 concrete beams embedded with a reinforcement at distance of 25 mm from top surface were prepared and sacrificial zinc anode plates were attached on top surface of specimens. 700 x 700 x 75 mm3 concrete slabs embedded with reinforcement mesh of 150 mm spacing were prepared and sacrificial anode were attached on top surface of concrete slabs at lower-left corner. The concrete beams and slabs were then exposed to wet-dry cycle and impressed voltage corrosion accelerations. The anode life was determined by time taken for total consumption of anode in concrete beams and the effective distance was determined by distance influenced by polarization effect of sacrificial anode in concrete slabs. Time taken for total consumption of anode and polarization effect were interpreted from corrosion potential data conducted in accordance with the ASTM C876. As a result, the anode life increased with increasing of concrete quality and decreased with increasing of the environmental severity. The effective distance was approximately 500-600 mm from the anode-installed position.

Experimental study on durability of red mud-blast furnace slag geopolymer mortar

Red mud (RM) is an industrial solid waste with high alkalinity. The preparation of RM as a geopolymer for construction is an effective means of recovery and treatment of RM. However, the durability of the geopolymer containing red mud is an important reason for restricting its promotion. In this paper, chloride ion permeability of geopolymer mortar and cement mortar was measured by two types of electric flux methods. Besides, corrosion potential and corrosion current of steel bars in geopolymer mortar and cement mortar conditioned in artificial climate and natural environment were studied, respectively. The results showed that the chloride ion resistance of the geopolymer was better than that of the cement mortar. The improved ASTM C1202 method was suitable for the evaluation of chloride ion permeability of geopolymer mortar since it could effectively solve the problem of long immersion time. The ASTM C876 Standard was not suitable for judging the corrosion state of steel bars in geopolymer mortar since the corrosion current method can better reflect the corrosion of steel bars in geopolymer than the corrosion potential method. The critical content of chloride ion in the geopolymer mortar (0.5 wt%) that causes the steel to passivate is significantly higher than that of cement mortar (0.3 wt%). Geopolymer mortar exhibited a stronger ability to protect steel bars from corrosion than cement mortar due to its density and resistance to ion penetration.

Ensemble machine learning model for corrosion initiation time estimation of embedded steel reinforced self-compacting concrete

Abstract Corrosion initiation time of embedded steel is an important service life parameter, which depends on concrete material make-up, exposure environment, and duration of exposure. Early and accurate determination of corrosion initiation time will aid in designing durable reinforced concrete, saves cost and time. This study leveraged on the power of ensemble machine learning by combining the performances of different models in estimating the corrosion initiation time of steel embedded in self compacted concrete using corrosion potential measurement. The concrete specimens were prepared with limestone powder as supplementary addition to Portland cement and was exposed to 5% sodium chloride in accordance with the requirements of ASTM C876 – 15 for 8 months. During the exposure, corrosion potential of the embedded steel was measured, and the recorded datasets were used in training five different machine learning models. With cement, limestone powder, coarse aggregate, fine aggregate, water and exposure period.as input variables, five different models were developed to estimate the corrosion initiation time (determined from the corrosion potential measurements) of the embedded steel. With respect to model predictive performance, the acquired results demonstrated that the random forest (RF) ensemble model amongst other trained models performed best with 85/15 dataset percentage split for the training and testing. RF ensemble performed best with CC and RMSE of 99.01% and 18.2747 mV for training, and 98.67% and 25.0298 mV for testing respectively. Hence, due to its superior and robust performance, this study proposes RF ensemble model in the estimation of corrosion initiation time of embedded steel in reinforced limestone-cement blend concrete.

The Effect of Stray Current from Sacrificial Anode Cathodic Protection (SACP) System on the Adjacent Unprotected Reinforcing Steel

Concrete protects reinforcing steel from corrosion, but the steel may be corroded if exposed to coastal environment. Cathodic protection is a popular method to protect steel structures from corrosion. Previous researchers have conducted studies on sacrificial anode cathodic protection (SACP). However, the effect of stray current on the unprotected reinforcing steel in concrete was not reported. This study aims to analyze the effect of the stray current phenomenon on reinforcing steel which are not protected by SACP. Three types of specimens were used in the study: (1) unconnected anode-cathode, (2) connected anode-cathode, and (3) partially connected anode-cathode. The specimens were treated with 30 weeks of wet-dry cycle. Half-cell potential technique was used to measure corrosion potential. The results show that the first specimen had an average potential value of -505.44 mV, meanwhile the second specimen had average potential value -883.66 mV. According to ASTM C876 criteria, the first specimen is categorized into high corrosion risk. While, the second specimen was protected from corrosion based on NACE standard. However, the result on the third specimen shows that only the first reinforcing steel was protected from corrosion, while the other steels were categorized as severe corrosion risk level. The result on third specimen indicates that the stray current produced by SACP system could cause negative effect on the reinforcing steel by increasing susceptibility to corrosion, instead of protecting them.

Durability of Reinforced Concrete Beams under Simultaneous Flexural Load in Corrosive Environment

The deterioration of concrete over time is the result of various mechanical, physical, chemical and biological processes, with the corrosion of reinforcement being the most serious problem of durability of reinforced concrete structures. Over the last 50 years, a tremendous effort has been spent by the international scientific community with laboratory research and experimental field studies in order to increase the resistance of concrete over corrosion. This paper presents an experimental study of the corrosion behaviour of reinforced concrete beams with simultaneous sustained flexural loading. For this purpose, 40 reinforced concrete beams of 5 different compositions were constructed and exposed in simulated harmful environmental conditions in 3 different stress ratios for a total period of 42 months. Their behavior against corrosion was determined via regular measurements of the electrical resistance of concrete (according to ASTM G57) and the corrosion potential of the steel-reinforced bars with the use of copper sulphate (CSE) as reference electrode (according to ASTM C876). A theoretical calculation of the corrosion rate was conducted based on the electrochemical measurements of the beams. The results indicate that the corrosion potential of steel decreased in time and more rapidly after the initiation of the corrosion process; the electrical resistance firstly increased, remained stable for a short period and then decreased with the corrosion development, as expected. An inversely proportional relationship of the water/cement ratio of a composition with its corrosion behaviour as well as an analogous relationship between the cement content of a composition and its corrosion behaviour was observed. Also, the corrosion rate of steel is increased gradually with increasing load.

Effects of vibration time on compressive strength and corrosion resistance of steel bars in concrete

In this paper, In this paper, effects of vibration time (0, 10 and 20 seconds) on compressive strength and corrosion resistance of steel bar in concrete are experimentally investigated. Compressive strength of concrete was performed on cylindrical specimens of Ø100x200 mm with water cement ratio (w/c) 0.52 after 28 days curing in tap water. Cylindrical specimens of Ø100x200 mm having 16 mm diameter of steel bar are considered for corrosion study. The specimens were subjected to cyclic wetting and drying regime up to 15 cycles. In wet cycle the specimens are immersed in sea water for 3 days, while in dry cycle the specimens were placed in open air for 4 days. The corrosion activity is monitored by measuring the copper/copper sulphate (CSE) half-cell potential according to ASTM C-876. The chloride penetration depths of concretes are also measured after 28 days immersed in 10% NaCl solution. Results show that compressive strength, chloride penetration depths and corrosion of steel bars is significantly affected by vibration time.

Strength and Durability Performance of Ferrocement Panels with the Influence of Corrosion Inhibitor

Success of Ferrocement, as with other construction material, depends largely upon its durability. ACI-549R strongly recommends that studies be undertaken to suggest durable and long-term anti-corrosion techniques to prevent penetration of water and salts that could lead to the corrosion of reinforcing wire mesh. The main objective of this study is to develop a durable Ferrocement panel by incorporating corrosion inhibitors as admixtures. The inhibitor used is sodium nitrate based inhibitor. Totally 24 Ferrocement panels are subjected to strength and durability study to ascertain the influence of inhibitor modification in cement mortar. Inhibitor admixed mortar offers marginally improved resistance against water absorption irrespective of tested dosage levels as compared to control mortar. There is a appreciable reduction in current development in the order of 18% for inhibitor admixed mortar as compared to control mortar, which is an indication of improved resistance against chloride penetration. Half-cell potential readings on galvanized Ferrocement panels should not be interpreted for corrosion probability as per ASTM C876. Ferrocement panels with crimped wire mesh and inhibitor modification offered low corrosion risk at the end of test period as per ASTM C876. There is an improvement in ultimate load carrying capacity for galvanized mesh Ferrocement panels of the order of 11-16% upon inhibitor modification in mortar. Similar ultimate load carrying capacity for crimped wire mesh Ferrocement panels for control and inhibitor modified mortar. Ductile behavior associated with multiple crack formation before failure is observed for all tested panels. It can be concluded that crimped wire mesh panel Ferrocement panels offered appreciable stiffness, load carrying capacity and ductility as compared to galvanized mesh Ferrocement panel. Inhibitor incorporation appreciably improves the durable performance of Ferrocement panels.

Effects of lightweight sand and steel fiber contents on the corrosion performance of steel rebar embedded in UHPC

Ultra-high-performance concrete (UHPC) is able to provide better protection for embedded steel rebar from corrosion due to its superior impermeability characteristics. Lightweight sand (LWS) and steel fibers are utilized in mixing UHPC to promote internal curing and improve flexural strength, respectively. But the effects of different contents of LWS and steel fibers on the corrosion performance of steel rebar and resistance of UHPC matrix are rarely investigated. In this study, steel bar reinforced UHPC specimens with different LWS and steel fiber contents were prepared for electrochemical tests, involving open circuit potential (OCP), Tafel polarization, linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS). The experiment results indicated OCPs values based on ASTM C876 could not be applied to decide the corrosion state of steel rebar since lower content of oxygen in UHPC reduced the cathodic reaction, which led to lower OCP values. Chloride ions did not penetrate into UHPC matrix and steel rebar were in passive state in the whole test period of 147 days (d). Corrosion resistance of steel rebar, and resistance of UHPC matrix and passive film displayed an increasing trend with time. Generally, the resistance decreased when the LWS and steel fiber contents were increased. This is because LWS increased the permeability of UHPC and steel fibers led to shortcut of current. For better electrical resistance and compressive strength of UHPC, it is recommended to limit the LWS replacement ratio to 25%. It is also concluded that, steel fiber with the volume content up to 3% will not lead to corrosion of steel rebar and can be safely used in UHPC.

Effect of Silica Fume and Fly Ash Admixtures on the Corrosion Behavior of AISI 304 Embedded in Concrete Exposed in 3.5% NaCl Solution.

The use of supplementary cementitious materials such as fly ash, slag, and silica fume improve reinforced concrete corrosion performance, while decreasing cost and reducing environmental impact compared to ordinary Portland cement. In this study, the corrosion behavior of AISI 1018 carbon steel (CS) and AISI 304 stainless steel (SS) reinforcements was studied for 365 days. Three different concrete mixtures were tested: 100% CPC (composite Portland cement), 80% CPC and 20% silica fume (SF), and 80% CPC and 20% fly ash (FA). The concrete mixtures were designed according to the ACI 211.1 standard. The reinforced concrete specimens were immersed in a 3.5 wt.% NaCl test solution to simulate a marine environment. Corrosion monitoring was evaluated using the corrosion potential (Ecorr) according to ASTM C876 and the linear polarization resistance (LPR) according to ASTM G59. The results show that AISI 304 SS reinforcements yielded the best corrosion behavior, with Ecorr values mainly pertaining to the region of 10% probability of corrosion, and corrosion current density (icorr) values indicating passivity after 105 days of experimentation and low probability of corrosion for the remainder of the test period.

CORROSION BEHAVIOR OF REINFORCING STEEL IN RC SLAB CONTAINING CHLORIDES WITH PARTIAL REPLACEMENT OF CEMENT AS FLY ASH

Steel reinforcement in concrete containing fly ash has been practically employed to RC structures in snowy cold region and coastal areas so that the durability of the structures against corrosion can be enhanced. In this research to make the compatibility with RC slab bridge sodium chloride solution of 10[WU1] % in concentration was applied on RC slab and corrosion development was monitored by electrochemical method. Applying fly ash in RC slab at two replacement levels of 15[WU2] % (F15) and 30% (F30) of cement the specimens were observed. The observation result verified that fly ash concrete showed longer period of corrosion initiation (ASTM C876) than normal reinforced concrete. The initiation period of corrosion was 4.5 and 6 times longer for F15 and F30 concrete than normal concrete, as well as 91 days strength of F30 concrete was about 14% higher that of norma concrete. Test result showed that fly ash has better influence on steel corrosion reduction than concrete cover increment. It was observed that fly ash concrete (F15 and F30) with 3 cm concrete cover has better corrosion resistivity than using 4 cm cover of non-fly ash concrete. Furthermore, using the same concrete cover (3 cm) it was found that the actual corrosion rate was decreased about 68 to 82% by adding fly ash 15 to 30% respectively compared to normal reinforced concrete. In addition, a significant attenuation in corrosion area in rebar between fly ash concrete and normal concrete was found. Based on actual corrosion area on rebar surface, actual corrosion current density was larger than corrosion current density found from non-destructive way. Moreover, further analysis was conducted for characterization of different corrosion products using Raman spectroscopy with 532 nm wave length. It revealed that the corrosion product (Oxides and Oxyhydroxides compound) were less in F15 and F30 concrete compared to normal concrete. Considering these results, the possibility of reduction of chloride induced corrosion in reinforced concrete structure using fly ash has confirmed.

Effect of steel fibers with galvanized coatings on corrosion of steel bars embedded in UHPC

Ultra-high-performance concrete (UHPC) is widely accepted for its super-high durability. However, the corrosion performance of steel reinforcing bars embedded in UHPC and the improved protection of UHPC cover to steel bars are seldom studied. Furthermore, whether using steel fibers in UHPC will accelerate or slow down the corrosion of steel bars is of special interest. In this study, the effects of two types of steel fibers with different galvanized coatings (brass and zinc coated fibers) on the electrical resistance of UHPC and corrosion resistance of embedded steel bars were investigated. Electrochemical tests were conducted for 1 year in 3.5 wt % NaCl solution. The tests included open circuit potential (OCP), linear polarization resistance (LPR), Tafel polarization, and electrochemical impedance spectroscopy (EIS). Test results showed that ASTM C876 was not applicable to UHPC to determine corrosion state of embedded steel bars based on the OCP values. This is because the dense microstructure of UHPC can limit the penetration of oxygen and significantly lower OCP values. The corrosion rates in terms of corrosion current densities of steel bars from the LPR and Tafel polarization tests showed a decreasing trend with time, hence indicating that the steel bars were in passive state. Furthermore, chloride was not detected in the UHPC matrix after the electrochemical tests. This proved that corrosion did not occur on the steel bar surface in the testing period. The electrochemical resistance of UHPC matrix, the resistance of passive film, and the charge transfer resistance of the steel bars from the EIS test displayed a long-term increasing trend. However, when the conductive steel fibers increased from 0 to 2%, by volume, the UHPC matrix resistance decreased by more than 40%. It was also found that the fiber type and fiber content did not affect the resistance of passive film and charge transfer resistance of embedded steel bars. Galvanic corrosion did not happen due to uniform distribution of the fibers along the cast specimens. When proper casting method was employed, both brass and zinc-coated steel fibers can be safely used in UHPC for fiber volume up to 2%.

Corrosion of Reinforced Concrete Structures Submerged by the 2004 Tsunami in West Aceh, Indonesia

The earthquake and tsunami of 26 December 2004 caused the infrastructure in Aceh’s West Coast region to be submerged by seawater and to require the rehabilitation and reconstruction. The infrastructure that was submerged in the tsunami might experience a decrease in strength due to corrosion attack and would unexpectedly collapse if an earthquake occurs even on a small scale. This study was conducted to examine the corrosion risk level of the infrastructures in Aceh’s West Coast region, Indonesia, which submerged by the 2004 tsunami. Three locations were chosen for the study, i.e., Suak Ribee, Ujong Kalak, and Padang Seurahet. The assessments were carried out in 2014 and 2015. Three to four columns in each of the buildings were selected for the assessment. The half-cell potential technique method which refers to ASTM C876 was used to obtain and analyze the assessment data. The results of the assessment show that the electrical potentials on the surface of concrete for the buildings which submerged by the tsunami were range between -100 and -450 mV (vs. Cu/CuSO4) and categorized into low to high corrosion risk level. Meanwhile, the electrical potentials for new buildings range between (-100) and (-350) mV which indicated low to medium corrosion risk. Hence, the corrosion actively occurred in the areas having medium to high corrosion risk. Also, it was found that the corrosion risk level for the building tends to increase by increasing time. Therefore, the prevention and/or rehabilitation is necessary for stopping the corrosion, and so the premature failure of the building might be avoided.

Revisiting the ASTM C876 standard for corrosion of reinforcing steel: On the correlation between corrosion potential and polarization resistance during the curing of different cement mortars

This paper presents a probabilistic analysis of almost 700 potential and polarization resistance measurements of reinforcing steel embedded in 15 types of mortars of different nature and chloride contamination levels exposed to controlled conditions of temperature and relative humidity. Besides indicating that the ASTM C876 standard can be a robust and reliable commissioning tool for strategic assets in terms of effectiveness of reinforcing steel passivation, results show that the polarization resistance values follow different probability density functions at different potential levels, which means they do correspond to distinct interfacial processes.