scholarly journals Técnicas aceleradas para evaluar la susceptibilidad a corrosión de aceros embebidos en morteros con adiciones minerales expuestos a cloruros

2015 ◽  
Vol 79 (2) ◽  
pp. 137
Author(s):  
Einner Peralta Muñoz ◽  
Ana María Aguirre ◽  
Ruby Mejía de Gutiérrez
Keyword(s):  
Astm C1202

Este artículo estudia el comportamiento a la corrosión de morteros reforzados de cemento portland, sin adiciones y con adiciones de metacaolín (MK) y humo de sílice (SF), en presencia de cloruros. La proporción de la adición utilizada en las mezclas fue del 10% en peso como reemplazo del cemento. Se prepararon prototipos sin y con acero de refuerzo. En los primeros se determinó la resistencia a la compresión, absorción, porosidad, y permeabilidad a los cloruros. Las probetas de mortero reforzado se expusieron a cloruros (NaCl 3,5%) y se aplicaron dos técnicas aceleradas de corrosión: ciclos de humectación-secado y voltaje impreso; en ambos casos se utilizó como ambiente de referencia agua potable. El avance del proceso de corrosión en el acero se evaluó mediante la técnica electroquímica de resistencia a la polarización lineal (LPR). Los resultados mostraron que tanto a 28 como a 90 días de curado, las adiciones aumentan la resistencia a la compresión del mortero y contribuyen positivamente a reducir la susceptibilidad del material cementicio a la permeabilidad de cloruros. De las adiciones evaluadas, se destaca el desempeño mecánico de la mezcla con 10% de MK, representado en un incremento del 51,9% respecto a cemento Portland ordinario (OPC). Los coeficientes de absorción capilar de los morteros adicionados fueron hasta un 31% menores que los correspondientes de OPC, lo cual coincide con la reducida permeabilidad a cloruros (≤ 1000 coulombios) evaluada con base en la Norma ASTM C1202. Respecto a los resultados de corrosión se aprecia la misma tendencia de comportamiento en las mezclas, independientemente de la técnica acelerada utilizada. El mejor desempeño corresponde a la mezcla que contiene MK, seguido de SF y OPC. Cabe anotar, que la corriente de corrosión en los prototipos OPC es reducida hasta en un 90% al incorporar MK. De las técnicas aceleradas empleadas en el presente estudio se sugiere utilizar la de voltaje impreso debido al corto tiempo de obtención de los resultados.

Effect of Aggregate Volume Fraction on the Charge Passed of Mortar and Concrete

2009 ◽  
Vol 405-406 ◽  
pp. 283-288 ◽  
Author(s):  
Quan Lin Niu ◽  
Chong Zhi Li
Keyword(s):  
Penetration Depth ◽  
Volume Fraction ◽  
Low Permeability ◽  
Chloride Permeability ◽  
Volume Fractions ◽  
Aggregate Fraction ◽  
Low Charge ◽  
Astm C1202 ◽  
The Relationship ◽  
Cl Permeability

Charge passed of mortars with different aggregate volume fractions was tested according to ASTM C1202, and the differential expression of the Ohm law was introduced to explain the relationship between charge passed data and aggregate fractions.Cl- penetration depth of the corresponding mortars and concretes was measured to illustrate the influence of the aggregate volume fraction on their chloride permeability. It was shown that the charge passed of mortar was negatively correlated with aggregate volume fractions, and high aggregate fraction bearing concrete with low charge passed did not necessarily mean low permeability. As a result, the influence of aggregate fraction on charge passed should be taken into consideration when charge passed data was employed to evaluate Cl- permeability of concrete.

Chloride Ions Penetration Resistance of New-Old Concrete

2011 ◽  
Vol 366 ◽  
pp. 518-521
Author(s):  
Zhi Min He ◽  
Jun Zhe Liu
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Beneficial Effect ◽  
Blast Furnace Slag ◽  
Penetration Resistance ◽  
Chloride Ions ◽  
Mineral Admixtures ◽  
Compound System ◽  
Astm C1202 ◽  
Furnace Slag

By use of ASTM C1202, this paper studied the influence of mineral admixtures on the chloride ions penetration resistance of the new-old concrete compound system. The results indicate that the performance of new-old concrete exert significant influence on the new-old concrete compound system. The addition of mineral admixtures improve the permeability properties of new-old concrete. Adding fly ash(FA) require a relatively longer time to get its beneficial effect. When 30% weight of cement is replaced by 10% FA and 20% ground blast furnace slag(GGBFS), the inclusion of 30% mineral admixtures significantly improve the chloride ions penetration resistance properties of the new-old concrete compound system at 28 days and 180 days.

scholarly journals Analysis of Chloride Penetration Into High Performance Concrete

2020 ◽  
Vol 3 (3) ◽  
pp. 295-305
Author(s):  
Silvija Mrakovčić ◽  
Natalija Bede ◽  
Ivan Ušić
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Concrete Structures ◽  
Chloride Penetration ◽  
Reinforced Concrete Structures ◽  
Wetting And Drying ◽  
Chloride Corrosion ◽  
Structure Degradation ◽  
Astm C1202

Corrosion of reinforcement is one of basic destruction mechanisms of reinforced concrete structures. In that sense, the most affected structures are those by the sea, especially their parts subjected to cycles of wetting and drying. Chlorides penetrate to concrete mostly by diffusion, faster if the concrete is more permeable, destructing reinforcement passive protection and causing its corrosion, reduction of reinforcement cross section and bearing capacity of the structure. Retardation of chloride corrosion that causes structure degradation in marine environment can be achieved by the usage of quality concrete with enhanced strength and permeability parameters in regards to ordinary concrete. Mixes of ordinary and high performance concrete with different ratio of silica fume have been made. Compressive strength and resistivity to chloride penetration have been tested on the specimens 28 days after mixing. The resistivity to chloride penetration has been determined by fast chloride penetration test according to ASTM C1202 standard, using appliance that measures electrical conductivity of concrete specimens. Based on test results, the suitability of building reinforced concrete structures by the sea using high performance concrete has been analysed.

Research on the Durability of Reinforced Chemically Bonded Ceramics-Based Concrete Structural Members in Marine Environment

2014 ◽  
Vol 1044-1045 ◽  
pp. 189-194
Author(s):  
Zhong Xin Li ◽  
Qi Dong ◽  
Zhuo Bin Wei
Keyword(s):  
Marine Environment ◽  
Accumulation Rate ◽  
Chloride Ion ◽  
Structural Members ◽  
Ion Permeability ◽  
Chloride Ion Penetration ◽  
Corrosion Experiment ◽  
Electric Flux ◽  
Astm C1202 ◽  
Weight Loss Ratio

In order to study the durability of reinforced chemically bonded ceramics-based concrete structural members in marine environment, both the experiment of chloride ion permeability-resistance and rapid corrosion experiment of rebar in the CBC concrete were conducted. The methods of ASTM C1202,RCM and NEL were used to comprehensively assess the ability of chloride ion permeability-resistance of CBC concrete, electric flux and unsteady migration coefficients were taken as estimate indexes, while in the rapid corrosion experiment of rebar under the condition of immersing-drying circulating, rusty accumulation rate and weight loss ratio were taken as estimate indexes. The results of experiments indicate that CBC concrete has strong resistibility for chloride ion penetration, however, it cannot protect the internal rebar effectively, for the reason that the rebar in this test has been seriously corroded.

scholarly journals Evaluation of the chloride penetration and service life of self-healing concretes activated by crystalline catalyst

2018 ◽  
Vol 11 (3) ◽  
pp. 544-563 ◽  
Author(s):  
P. HELENE ◽  
G. GUIGNONE ◽  
G. VIEIRA ◽  
L. RONCETTI ◽  
F. MORONI
Keyword(s):  
Compressive Strength ◽  
Service Life ◽  
Blended Cement ◽  
Good Alternative ◽  
Chloride Ions ◽  
Self Healing ◽  
Chloride Permeability ◽  
Concrete Mixtures ◽  
Colorimetric Indicator ◽  
Astm C1202

Abstract The main cause of concrete structures deterioration is related to the resistance against the penetration of aggressive agents. Aiming at increase the impermeability and reduce the diffusivity of concrete elements, making it less susceptible to the ingress of chloride ions, the use of crystalline catalyst emerges as a good alternative. Its mechanism of autogenous healing enhances the natural pore-filling process of concrete. The aim of this study is to investigate the influence of the use of crystalline catalyst on the chloride ions penetration and service life prediction of concrete. For the concrete mixtures production, it was used blast-furnace slag blended cement, three different water/cement (w/c) ratios (0.45; 0.55; 0.65), with and without crystalline catalyst, totaling six different mixtures. The concrete specimens were cured in a moist chamber and tested at 28 and 91 days. It was performed tests of compressive strength, rapid chloride permeability (ASTM C1202:12), and silver nitrate colorimetric indicator. The results show that, compared to the reference mixture, the use of crystalline catalyst conserved the compressive strength and reduced the chloride ions penetration up to 30%, increasing service life up to 34%.

Study on Improvement of Concrete Durability by Using High Performance Cement

2006 ◽  
Vol 302-303 ◽  
pp. 204-210
Author(s):  
Nai Qian Feng ◽  
Quan Lin Niu ◽  
Jun Wang Cai ◽  
Chong Zhi Li ◽  
Ren Chang Huang
Keyword(s):  
High Performance ◽  
Chloride Ion ◽  
Saline Soils ◽  
Low Grade ◽  
Concrete Durability ◽  
Positive Role ◽  
Soil Corrosion ◽  
Bar Test ◽  
Mortar Bar ◽  
Astm C1202

Sulphate ion and chloride ion existed in the alkaline saline soils may cause serious problems on the durability of reinforced concrete structures, while it is found that superfine mineral powder plays positive role in the precaution of the alkaline saline corrosion. A composite cement named high performance cement (H.P.C) composed of clinker, metakaolin and fly ash powder in appropriate proportions is developed with good performance in preventing concrete from alkaline saline soil corrosion. Mortar bar test and visual examination showed that the cement could effectively control AAR and sulphate ion related expansion, and the charge passed tested according to ASTM C1202 was decreased to “negligible” level for concrete with W/B ratio of 0.3, and “very low” grade for concrete with W/B ratio of 0.45 and 0.55 when the high performance cement was used. Other properties such as low hydration heat and anti-freezing properties, as well as the uniformity of the fresh concrete (with no bleeding and segregation), made it an important material in the construction of concrete structure in alkaline saline soils.

Chloride Ions Penetration Resistance of Steam-Cured Concrete for Railway Precast Elements

2011 ◽  
Vol 219-220 ◽  
pp. 1419-1422
Author(s):  
Zhi Min He ◽  
Jun Zhe Liu ◽  
Tian Hong Wang
Keyword(s):  
Blast Furnace Slag ◽  
High Performance ◽  
Penetration Resistance ◽  
Chloride Ions ◽  
Mineral Admixtures ◽  
Concrete Mix ◽  
Binder Type ◽  
Precast Elements ◽  
Astm C1202 ◽  
Furnace Slag

By use of ASTM C1202, this paper studied the influence of mineral admixtures on the chloride ions penetration resistance of the steam-cured concrete. The experimental results indicated that mineral admixtures improved the permeability properties of high-performance concretes, but at different rates depending on the binder type. FA required a relatively longer time to get its beneficial effect. For each 10%~40% replacement of OPC by FA in a concrete mix, the values of coulomb charge of steam-cured and standard curing concrete reduces by 8%~17% at180 days. When 30% weight of the OPC were replaced by FA and ground blast furnace slag(GBFS), the inclusion of 30% mineral admixtures provided a significant improvement to the chloride ions penetration resistance properties of steam-cured and standard curing concrete at 28 days and 180 days, especially for the combination of 10% FA and 20% GBFS (double adding).

Chloride Diffusion Property of Recycled Aggregate Concrete Treated with Water Repellent Agents-Silane

2010 ◽  
Vol 168-170 ◽  
pp. 755-761
Author(s):  
Ya Guang Zhu ◽  
Jian Guo Dai ◽  
Qiu Yi Li
Keyword(s):  
Treatment Method ◽  
Recycled Aggregate Concrete ◽  
Test Method ◽  
Recycled Aggregate ◽  
Chloride Diffusion ◽  
Water Repellent ◽  
Diffusion Property ◽  
Aggregate Concrete ◽  
Astm C1202 ◽  
Better Than

Silane-base water repellent agents can significantly suppress the capillary water absorption of concrete and consequently improve the durability of the concrete and protects the internal steel reinforcement. This paper presents test result on chloride diffusion property of natural and recycled aggregate concrete externally and internally treated with silane-based water repellent agents based on the ASTM C1202 test method. The effects of concrete cracks on the chloride diffusion property were also investigated. After the tests, the impregnation depth of silane into the natural and recycled aggregate concrete, the total charges passing the testing samples and penetration depth of chloride during the testing period were determined. It was found that, for both cracked and uncracked concrete, externally treated natural and recycled aggregate concrete performed better than internally treated ones. The water repellent treatment method is more effective for recycled aggregate concrete than natural aggregate concrete because a deeper impregnation depth can be achieved in the former case.

Relationship between Test Results of the ACSIRO and ASTM C1202 Methods

2006 ◽  
Vol 302-303 ◽  
pp. 567-571 ◽  
Author(s):  
Wei Wen Li ◽  
Fa Guang Leng ◽  
Xiong Zhou Yuan
Keyword(s):  
Standard Test ◽  
Total Charge ◽  
Test Results ◽  
Additional Test ◽  
Simple Modification ◽  
Concrete Quality ◽  
The Difference ◽  
Astm C1202 ◽  
The Relationship

The ASTM C1202 method is observed that the total electric charge passed is not an ideal indicator for classification of concrete quality when different binders are considered. Considering the drawback of the ASTM 1202 method, a simple modification to the ASTM C1202 method is recommended. The modification involves an additional test using curing water as electrolyze solution. The difference in the total charge passed obtained between standard test and test performed in curing water is suggested as an indicator for concrete quality. The test results show that there exists a good correlation between the ACSIRO and the ASTM C1202 methods. The relationship can be formulated as a linear function.

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