Effect of Surface Applied Inhibitor on Corrosion Rate of Steel Bar in High Strength Concrete with Various Admixed Chlorides

2012 ◽  
Vol 174-177 ◽  
pp. 1184-1187 ◽  
Author(s):  
Wen Jian Lan ◽  
Baohong Wu ◽  
Zhi Yong Liu
Keyword(s):  
Corrosion Rate ◽  
High Strength Concrete ◽  
Electrochemical Impedance ◽  
High Strength ◽  
Chloride Content ◽  
Corrosion Current ◽  
Cementitious Materials ◽  
Strength Concrete ◽  
Average Corrosion Rate ◽  
Effect Of Surface

Effect of surface applied inhibitor on the durability of high strength reinforced concrete with various chloride content has been investigated in this paper. The C60 concrete specimens contaminated with 0.5%,1.0%,1.5% NaCl by mass of the cementitious materials were prepared and experienced in months exposure tests after painting with 400 g/m2 inhibitor. The electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) of the steel rebar in specimens was tested. The results indicate that after surface painting the inhibitor for 28d the bars in concrete specimens with 0.5% NaCl and bar with 25mm cover in specimen with 1% NaCl show the average corrosion rate lower than that of control one (No.0, no painted inhibitor). While the corrosion current of rebar (38mm cover) for No.2 specimen with 1% NaCl and bars for No.3 specimen with 1.5% NaCl are still higher than that of the control one (No.0). The results indicate that the surface painted inhibitor on C60 concrete are effective to inhibit the corrosion of bar concrete at low or middle chloride conditions and not enough to repair the bars in high chloride contaminated concrete. The lower organic nitrogen content in 40-50mm depth also indicates that the inhibitor is harder to penetrate into deeper parts of high strength concrete compared with low or middle grade concrete.

Effect of Migrating Corrosion Inhibitor on Corrosion Rate of Reinforcing Steel in Concrete with Various Admixed Chloride

2012 ◽  
Vol 204-208 ◽  
pp. 3146-3150 ◽  
Author(s):  
Zhi Yong Liu ◽  
Xin Gang Zhou ◽  
Xiu Lin Li
Keyword(s):  
Corrosion Rate ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Cementitious Materials ◽  
Steel Bar ◽  
Average Corrosion Rate ◽  
Corrosion Of Steel ◽  
High Chloride ◽  
Effect Of Surface ◽  
Chloride Contaminated

Effect of surface applied inhibitor on the durability of chloride contaminated reinforced concrete has been investigated in this paper. The C30 concrete samples contaminated with 0.5%,1.0%,1.5% NaCl by mass of the cementitious materials in the mixing process were experienced adequate curing and subjected to 1 months exposure tests after painting with 400 g/m2 MCIs. The corrosion behavior of the steel rebar in concrete samples was monitored by using electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and corrosion currents. The results indicate that, after painting the MCIs for 28d on the surface of concrete samples with 0.5% and 1% NaCl, the average corrosion rate of reinforcements in concrete samples （0.34μA/cm2 ）is lower than that of the control one (No.0, no painted inhibitor), and about 1/4 of the initial corrosion current of the samples with 0.5% and 1% NaCl before painting MCI. But the corrosion current of rebar in No.3 sample with 1.5% NaCl is still higher than that of the control one (No.0). Therefore, painting MCIs on the surface of samples is very effective to inhibit the corrosion of steel bar in concrete at low or middle chloride conditions, but it is not enough to repair severely corroded steel bar in high chloride contaminated concrete.

scholarly journals Efficacy of Natural Zeolite and Metakaolin as Partial Alternatives to Cement in Fresh and Hardened High Strength Concrete

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Iswarya Gowram ◽  
Beulah M ◽  
MR Sudhir ◽  
Mothi Krishna Mohan ◽  
Deekshith Jain
Keyword(s):  
High Strength Concrete ◽  
Natural Zeolite ◽  
Environmental Concern ◽  
Concrete Strength ◽  
High Strength ◽  
Cementitious Materials ◽  
Partial Replacement ◽  
Split Tensile Strength ◽  
Carbon Footprints ◽  
Strength Concrete

Urbanization and industrialization have dramatically increased the manufacture of cement causing substantial pollution of the environment. The primary global concern related to cement manufacture has been the management of the large carbon footprints. The usages of environmentally friendly cementitious materials in the construction of structures have proved to be a viable option to deal with this environmental concern. Therefore, it is necessary to further explore the usage of cementitious materials which can replace cement albeit partially. In this direction of research, two such cementitious materials, namely, natural zeolite and metakaolin have been investigated in this study. High-strength concrete M60 with natural zeolite and metakaolin as the partial replacements for the cement has been prepared in this work. Polycarboxylic ether-based superplasticizer solution has been used to enhance workability. The test specimen cast and cured for 3, 7, 28, 60, and 90 days at ambient room temperature has been tested for compressive strength, split tensile strength, and flexural strength as per the Indian standards. The optimum mix of high-strength concrete thus manufactured has met the Indian standards, and the combination of cement +5% natural zeolite +10% metakaolin has exhibited the highest compressive, split tensile, and flexural strengths at 90 days of curing. Natural zeolite and metakaolin when used in smaller proportions have increased the concrete strength, and these materials are recommended for partial replacement of cement.

Research on Mechanical Properties of C100 High-Strength Concrete Used for Frozen Shaft

2012 ◽  
Vol 598 ◽  
pp. 388-392
Author(s):  
Hong Qiang Chu ◽  
Lin Hua Jiang ◽  
Ning Xu ◽  
Chuan Sheng Xiong
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Fly Ash ◽  
High Strength Concrete ◽  
High Strength ◽  
Cementitious Materials ◽  
Poisson's Ratio ◽  
Strength Concrete ◽  
Tensile Elastic Modulus ◽  
Early Strength

The mechanical properties of C100 high-strength concrete used for frozen shaft were studied in this research. The results demonstrate that: The cementitious materials 570kg/m3 concrete 28 strength is only 104.5MPa, which is lower than the C100 requirements; the early strength (3d) of the concrete doped with 30% admixture is less than 20% admixture concrete, but with the age increase, its strength gradually reaches close to concrete doped with 20% admixture, and eventually exceeds the concrete doped with 20% admixture.The tension-compression of high strength concrete doped with 15% fly ash and 15% slag is the smallest, while the tension-compression of the concrete doped 10% fly ash and 10% slag reaches the maximum.The Poisson's ratio of C100 concrete is between 0.20 and 0.24; the compressive elastic modulus is about 50GPa; and the tensile elastic modulus is about 110GPa.

scholarly journals Lightweight high-strength concrete with the use of waste cenosphere as fine aggregate

2019 ◽  
Vol 24 (4) ◽  
Author(s):  
Felipe Basquiroto de Souza ◽  
Oscar Rubem Klegues Montedo ◽  
Rosielen Leopoldo Grassi ◽  
Elaine Gugliemi Pavei Antunes
Keyword(s):  
High Strength Concrete ◽  
Power Plants ◽  
Lightweight Concrete ◽  
Construction Materials ◽  
Hollow Structure ◽  
High Strength ◽  
Cementitious Materials ◽  
Partial Substitution ◽  
Fine Aggregate ◽  
Strength Concrete

ABSTRACT Cenosphere is a coal combustion by-product that presents interesting properties to be used in the production of cementitious materials, such as hollow structure, low density, low thermal conductivity and notably thermal stability. In addition, it displays pozzolanic reactivity under thermal curing. However, the cenosphere potential for the development of unique construction materials has not been fully investigated, remaining obscure for both power plants and the construction field. This study investigated the employment of waste cenosphere in partial substitution to sand for the obtainment of high-strength lightweight concrete materials. Cenosphere from a Brazilian power plant was chemically and physically characterized and the feasibility of its use in concretes was investigated. It was discovered that the power plant’s fly ash is composed of approximately 0.2% of cenosphere. In addition, the cenosphere displayed size ranging from 30 to 300 µm and were suitable for use as fine aggregate in concrete. Concrete with 33, 67, and 100% fine aggregate replacement by the waste cenosphere was produced. Cenosphere-based high strength concrete presented strength higher than 70 MPa and density as low as 1500 kg • m-3. Compared to mixes of reference, cenosphere application as fine aggregate improved the specific strength of high-strength concrete while maintaining equivalent mechanical properties.

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