Inhibition and compressive-strength performance of Na2Cr2O7and C10H14N2Na2O8·2H2O in steel-reinforced concrete in corrosive environments

Loto

Popoola

2016

Metals

This paper investigates Phyllanthus muellerianus leaf-extract effects on steel-reinforcement corrosion in concrete immersed in 3.5% NaCl, simulating saline/marine environment. Different concentrations of the leaf-extract were admixed in steel-reinforced concrete samples, which were immersed, with normal control, in the test-environment, while positive control samples were immersed in distilled water. Electrochemical measurements of corrosion-rate (by linear-polarizationresistance instrument), corrosion-current (by zero-resistance-ammeter) and corrosion-potential (by high impedance multimeter) were obtained for assessing the reinforcing-steel corrosion. Analyzed results showed that the corrosion-rate exhibited excellent correlation (R = 98.82%, Nash-Sutcliffe Efficiency = 97.66%, ANOVA p-value = 0.0006) with function of the admixture concentration and of the corrosion noise-resistance (ratio of corrosion-potential and corrosion-current standard deviations). The 0.3333% Phyllanthus muellerianus (per weight of cement) exhibited optimal efficiency, η = 97.58% ± 1.28% (experimental) or 95.33% ± 4.25% (predicted), at inhibiting concrete steel-reinforcement corrosion in the test-environment, which compares well with the positive control performance model, η = 97.96% ± 0.03%. The experimental and predicted models followed the Langmuir adsorption isotherm, which indicated physisorption as the Phyllanthus muellerianus leaf-extract adsorption mechanism on the reinforcing-steel. These support suitability of the N-, S-, and O-containing and π-electron rich Phyllanthus muellerianus leaf-extract as an environmentally-friendly inhibitor for effective corrosion-protection of steel-reinforcement in concrete designed for the saline/marine environment.

Section: Methodsmentioning

confidence: 99%

Effects of Phyllanthus muellerianus Leaf-Extract on Steel-Reinforcement Corrosion in 3.5% NaCl-Immersed Concrete

Loto

Popoola

2016

Metals

“…It is worth noting that all steel-reinforced concrete samples in this first set were cured in curing room for 28 days [67,68], as per ASTM C192/192 M-16a [65]. The second set of steelreinforced concrete samples includes three samples that were cast in similar manner to the samples for electrochemical experiment (the first set) but with 0.00% admixture and which were cured in water for 28 days [11,41,69]. These samples of the second set are not subjected to electrochemical corrosion monitoring but are employed in the study as control samples for the compressive-strength testing according to the specification from ASTM C267-01(2012) [70].…”

Section: 13mentioning

confidence: 99%

“…The steel-reinforced concrete samples for the electrochemical experiments were subjected to compressivestrength testing after the 96-day postcorrosion medium immersion testing by following the prescription from ASTM C39/C39 M-17b [74] and as detailed in [41,46]. For this compressive-strength testing, the Model YES 2000, hydraulically powered, compression testing machine, from Eccles Technical Engineering Ltd5, England, was used.…”

Section: Compressive-strength Testing Of Steel-reinforced Concrete Samentioning

confidence: 99%

“…These challenges are causing increasing restrictions in many countries on their usage [15,[38][39][40]. The additional problem from this includes the fact that these compounds constitute highly effective corrosion inhibitors such that replacement for them is difficult [41,42]. Research tests are required for novel corrosion inhibitor proposition that will be environmentally friendly, nontoxic, and nonhazardous to the environmental ecosystem.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cymbopogon citratusand NaNO₂Behaviours in 3.5% NaCl-Immersed Steel-Reinforced Concrete: Implications for Eco-Friendly Corrosion Inhibitor Applications for Steel in Concrete

Popoola

International Journal of Corrosion

2018

Self Cite

This paper studies behaviours of Cymbopogon citratus leaf-extract and NaNO 2 , used as equal-mass admixture models, in 3.5% NaCl-immersed steel-reinforced concrete by nondestructive electrochemical methods and by compressive-strength improvement/reduction effects. Corrosion-rate, corrosion-current, and corrosion-potential constitute electrochemical test-techniques while compressive-strength effect investigations followed ASTM C29 and ASTM C33, in experiments using positive-controls for the electrochemical and compressive-strength studies. Analyses of the different electrochemical test-results mostly portrayed agreements on reinforcing-steel anticorrosion effects by the concentrations of natural plant and of chemical admixtures in the saline/marine simulating-environment and in the distilled H 2 O (electrochemical positive control) of steel-reinforced concrete immersions. These indicated that little amount (0.0833% cement for concrete-mixing) of Cymbopogon citratus leaf-extract was required for optimal inhibition efficiency, = 99.35%, on reinforcing-steel corrosion, in the study. Results of compressive-strength change factor also indicated that the 0.0833% Cymbopogon citratus concentration outperformed NaNO 2 admixture concentrations also in compressive-strength improvement effects on the NaCl-immersed steel-reinforced concrete. These established implications, from the study, on the suitability of the eco-friendly Cymbopogon citratus leaf-extract for replacing the also highly effective NaNO 2 inhibitor of steel-in-concrete corrosion in concrete designed for the saline/marine service-environment.

Advances in Materials Science and Engineering

“…The influences of F-T cycles on ultrasonic velocity and mechanical properties of air-entrained concrete and plain concrete were analysed. Also, accelerated aging test or simulative environmental test is adopted in [12][13][14][15][16][17][18], which shows that it is convenient and time saving to adopt such experimental method to study the environmental effects on concrete properties. However, there are apparent differences between real service condition and artificial environment, since the latter can merely reproduce several environmental factors, such as sulphate, chloride ion, acid, high temperature, and humidity.…”

Section: Introductionmentioning

confidence: 99%

Correlation between the Compressive, Tensile Strength of Old Concrete under Marine Environment and Prediction of Long-Term Strength

Yao

Jiang

Wei

et al. 2017

Compressive strength and tensile strength are important mechanical properties of concrete. The long-term strength of concrete under real service environment is an important parameter when evaluating existing buildings, which should also be properly considered in structural design. In this study, the relationship between compressive and splitting tensile strength of old concrete existing for long period under marine environment was investigated. At a deserted harbour, concrete cores samples were drilled by pairs in site. For each pair of samples, the two cores were drilled from the adjacent location and conducted to compressive, splitting tensile test, respectively. 48 compressive and splitting tensile strengths were finally obtained. From the test results, tensile strength presents general uptrend with compressive strength, and the two parameters are well positively correlated. Exponential model generally recommended by building codes or literatures is still capable of describing the relationship between compressive and tensile strength of old deteriorated concrete, when function parameters are properly determined. Based on statistical theory and the experimental result of this study, a method for predicting long-term tensile strength of concrete is developed and an example is given, which may provide a potential way to estimate long-term concrete strength under real marine environment.