Experimental Study on Improvement Mechanism of Silane Emulsion on Acid Rain Corrosion of Green Ecological Concrete

2020 ◽  
Vol 12 (6) ◽  
pp. 873-883
Author(s):  
Wei Xun Hu ◽  
Yao Zhuang Li ◽  
Hua Peng
Keyword(s):  
Compressive Strength ◽  
Service Life ◽  
Acid Rain ◽  
Concrete Structure ◽  
Test Group ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Test Time ◽  
Ratio Test ◽  
Mixing Ratio

Concrete structure is vulnerable to acid rain corrosion, which affects the service life of the material, in the corrosive environment, and concrete structure will deteriorate because of the erosion of water/chloride ions. Therefore, waterproof treatment of concrete structure is needed to improve the durability of the structure. In this study, the green ecological concrete is taken as the research object. The concrete is mixed with a certain amount of silane emulsion to reduce the probability of corrosion of concrete due to moisture and chloride ions, thereby prolonging the service life of this kind of concrete. During the experiment, in order to further test the corrosion resistance of silane emulsion to this kind of concrete, different kinds of concrete were taken as test objects and divided into 3 test groups, namely, the original test group (ITE), the non silane emulsion test group (TWSE) and the optimal ratio test group (OT-SE). It is proved by experiments that the best proportion of concrete mixed with silane emulsion is 0.32 of water binder ratio, 18% of coal powder mixing ratio, 37% of gravel mixing ratio and 0.23% of proportion of silane emulsion. The above factors are applied to compressive strength test, and 30 days as test time, the compressive strength of concrete with fly ash is measured. In the experiment of anticorrosion, compared with the traditional concrete samples, the electrical flux of concrete mixed with silane emulsion decreased by 28.7% in 8 h, that is, chloride ion permeability decreased significantly.

An Experimental Corrosion Investigation of Coupling Chloride Ions with Stray Current for Reinforced Concrete

2012 ◽  
Vol 166-169 ◽  
pp. 1987-1993 ◽  
Author(s):  
Mengcheng Chen ◽  
Kai Wang ◽  
Quanshui Wu ◽  
Zhen Qin
Keyword(s):  
Reinforced Concrete ◽  
Chloride Ion ◽  
Current Strength ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Test Time ◽  
Light Rail ◽  
Stray Current ◽  
Concrete Deterioration ◽  
Two Stages

According to the service environment of light rail transit and subway structures, in this paper experiments on the corrosion characteristics of reinforced concrete under single corrosion environment of stray current, single corrosion environment of chloride ions and joint corrosion environment of stray current and chloride ions were respectively carried out. Loading direct current electric field was used to simulate the stray current. The experimental results showed that, the corrosion growth process of the rebar in reinforced concrete under single environment of chloride ions was slow and stable, while that under single environment of stray current being separated two stages, i.e., rapidly increasing stage and stably varying stage. In addition, the rebar of reinforced concrete in stray current alone environment was corroded faster than that in chloride ion alone environment did; when stray current and chloride ion coexist, the stray current speeded up the chloride ion transportation, which gave rise to the increase of the corrosion rate of the rebar of reinforced concrete; the corrosion degree of the rebar depended on the chloride ion concentration, stray current strength and test time. The stronger the stray current strength, the longer the stray current corrosion period and the heavier the chloride ion concentration, the more the corrosion products of the rebar and thus the more serious the reinforced concrete deterioration.

scholarly journals A review on performance – based specification of durable concrete

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Elson John ◽  
Goldy Prince ◽  
Jessymol George
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Service Life ◽  
Low Cost ◽  
General Assumption ◽  
Chloride Ions ◽  
Actual Structure ◽  
Strength Performance ◽  
Rc Structures ◽  
Performance Specification

Concrete is the most common and widely used building material because of its relatively low cost, flexibility, and adaptability. Recent historical experience indicates that with exposed to aggressive chloride or carbonation-induced conditions, the reinforced concrete (RC) structures deteriorate prior to the expected service life. This is because of the general assumption that the concrete must be sufficiently durable if the strength requirements are adequate. The variability of concrete arising from the actual concreting procedures, such as placement, consolidation, finishing, and curing, does not take this assumption into account. In other words, the concrete cast for compressive strength in the specimens shows no similarity to the concrete in the actual structure. This paper provides a thorough analysis of the advancements that are taking place to achieve the long-term reliability of RC structures based on performance specifications. Keywords: reinforced concrete, service life, compressive strength, performance specification, durability, carbonation, chloride ions

scholarly journals Evaluation of Chloride Resistance of Early-Strength Concrete Using Blended Binder and Polycarboxylate-Based Chemical Admixture

2020 ◽  
Vol 10 (8) ◽  
pp. 2972 ◽  
Author(s):  
Taegyu Lee ◽  
Jaehyun Lee
Keyword(s):  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Portland Cement ◽  
Chloride Ion ◽  
Strength Criterion ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Characteristic Strength ◽  
Early Strength

The mixing proportions of concrete were examined with regard to the durability performance and early strength in coastal areas. Research was conducted to improve the C24 mix (characteristic strength of 24 MPa). C35 concrete (characteristic strength of 35 MPa) was selected as a comparison group, as it exhibits the minimum proposed strength criterion for concrete in the marine environment. To secure the early strength of the C24 concrete, 50% of the total ordinary Portland cement (OPC) binder was replaced with early Portland cement (EPC); and to provide durability, 20% was substituted with ground granulated blast-furnace slag (GGBS). In addition, a polycarboxylate (PC)-based superplasticizer was used to reduce the unit water content. The compressive strength, chloride ion diffusion coefficient, chloride penetration depth, and pore structure were evaluated. After one day, the compressive strength improved by 40% when using EPC and GGBS, and an average increase of 20% was observed over 91 days. EPC and GGBS also reduced the overall porosity, which may increase the watertightness of concrete. The salt resistance performance was improved because the rapid early development of strength increased the watertightness of the surface and immobilization of chloride ions, decreasing the chloride diffusion coefficient by 50%.

Penetration of Chlorine Ion in Concrete under the Coupling Effect of the Continues Pressure Load and the Corrosion Environment

2014 ◽  
Vol 633 ◽  
pp. 140-144
Author(s):  
Wei Hong Li ◽  
Ying Ying Xu
Keyword(s):  
Penetration Depth ◽  
Coupling Effect ◽  
Chloride Ion ◽  
Load Level ◽  
Chloride Ions ◽  
Diffusion Method ◽  
Test Time ◽  
Environment Interaction ◽  
Concrete Durability ◽  
Pressure Load

This paper studies the influence law of experiment time, load level under sustained pressure load and the corrosion environment interaction on the permeability of chloride ion in concrete,which is through natural diffusion method. Experimental results show that with the increase of the test time, the penetration depth of chloride ions in concrete and the content of chloride ions in the same penetration depth is growing. As the load level increases, there is a tendency of the chloride ion content after the first increase and then decrease, the turning point in the middle remains to be studied. The research results have a certain significance for concrete durability design and life prediction in corrosion environment.

REDUCTION OF CHLORIDE ION INGRESS INTO REINFORCED CONCRETE USING A HYDROPHOBIC ADDITIVE MATERIAL

2017 ◽  
Vol 79 (2) ◽  
Author(s):  
Agus Maryoto ◽  
Buntara S. Gan ◽  
Han Aylie
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Calcium Stearate ◽  
Corrosion Attack ◽  
Reinforced Concrete Member ◽  
Load Carrying ◽  
Compressive Strength Test ◽  
Infiltration Test

Reinforced concrete structures located in areas near the coast are exposed to potential corrosion attack. Corrosion attack can occur because of the infiltration of chloride ions into concrete. At the initiation of the corrosion process, the load-carrying capacity of a reinforced concrete member will be affected negatively as a function of time. Infiltration of chloride ions into the concrete could be avoided by improving the micro-concrete properties. Enhancement of these properties can be achieved by use of an additive in the concrete. Calcium stearate is a hydrophobic material that can improve the properties of concrete. To determine the optimum contribution in concrete, laboratory experiments were conducted. Calcium stearate was added in varying contents of 0, 0.2, 0.9, and 1.9% of the cement weight. Four types of tests were performed to analyse the contribution of calcium stearate, namely the compressive strength test, absorption test, chloride ion infiltration test, and corrosion test. The results show that an optimum value of the compressive strength of concrete is obtained through the addition of calcium stearate. Besides that, the absorption, chloride ion infiltration, and corrosion value decrease significantly when a higher amount of calcium stearate is added to the concrete.  

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 the Durability of Concrete Structure of Aviation Oil Wharf of Shenzhen Airport

2010 ◽  
Vol 163-167 ◽  
pp. 1019-1023
Author(s):  
Wei Lun Wang ◽  
Ji Hua Zhu ◽  
Feng Xing
Keyword(s):  
Service Life ◽  
Concrete Structure ◽  
Chloride Ion ◽  
Ion Concentration ◽  
Ion Diffusion ◽  
Cell Potential ◽  
Shenzhen City ◽  
High Possibility ◽  
Chloride Ion Diffusion ◽  
Existing Structure

Due to the invasion of chloride ion, the reinforcement in coastal concrete structure is corroded, which causes damage to the concrete structure and becomes the major factor affecting the structure’s service life. Aiming at the existing concrete structure under the coastal environment of Shenzhen City, the durability experimental study has been implemented, discussing the main reason for the insufficient durability of the existing structure. The experiment result shows that the higher chloride ion diffusion coefficient (76.1×10-12 m2/s) in the concrete structure leads that the chloride ion concentration of the structure in the depth of 30mm surpasses one percent upon using it for two decades. The half-cell potential value also reflects the relatively high possibility of the reinforcement corrosion of the structure. Combining with the experiment result, the service life of this concrete structure has been analyzed, which is hard to be guaranteed to use for five decades under the current concrete parameters and resistance.

scholarly journals The Compressive Strength and Resistivity toward Corrosion Attacks by Chloride Ion of Concrete Containing Type I Cement and Calcium Stearate

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Agus Maryoto ◽  
Buntara Sthenly Gan ◽  
Nor Intang Setyo Hermanto ◽  
Rachmad Setijadi
Keyword(s):  
Compressive Strength ◽  
Chloride Ion ◽  
Concrete Surface ◽  
Chloride Ions ◽  
Calcium Stearate ◽  
Type I ◽  
Compressive Strength Test ◽  
Strength Tests ◽  
Concrete Quality ◽  
Infiltration Test

This study aims to determine the effect of calcium stearate on concrete. Three kinds of concrete quality are studied, namely, 20, 30, and 40 MPa. Tests performed in the laboratory comprise a compressive strength test and an infiltration test of chloride ion content. The specimens used were cylinders with a diameter of 150 mm and height of 300 mm. The chloride ion infiltration test was carried out on a cube with sides of 150 mm. The infiltration of ions into the concrete was examined at depths of 1, 2, 4, 6, and 8 cm. Four dosages of calcium stearate were added to the concrete, namely, 0, 0.25, 1.27, and 2.53% for 20 MPa concrete; 0, 0.21, 1.07, and 2.48% for 30 MPa concrete; and 0, 0.19, 0.90, and 1.87% for 40 MPa concrete. The results of compressive strength tests indicate that the amount of calcium stearate that could be safely applied to the concrete was 0.25% of the weight of cement. On the other hand, the infiltration of chloride ions at a depth of 6 cm from the unprotected concrete surface decreased by 87, 69, and 113% for the 20, 30, and 40 MPa concrete, respectively, compared to concrete without calcium stearate. The test shows that the use of calcium stearate in concrete significantly increases its resistivity against corrosion attacks because, in the absence of chloride ions, the process of corrosion does not take place in the concrete.

scholarly journals The Impact of Chloride and Sulphate Aggressiveness on the Microstructure and Phase Composition of Fly Ash-Slag Mortar

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4430
Author(s):  
Paweł Falaciński ◽  
Agnieszka Machowska ◽  
Łukasz Szarek
Keyword(s):  
Compressive Strength ◽  
Phase Composition ◽  
Sodium Chloride ◽  
Chloride Ion ◽  
Sodium Sulphate ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Pore Liquid ◽  
A Minor ◽  
The Impact

The article discusses the results of examining the impact of aggressive solutions on specimens of mortars with a slag-ash binder. Bar specimens were exposed to unidirectional diffusion of sodium chloride and sodium sulphate for 90 days. Next, the specimens were subjected to flexural and compressive strength tests, ion content tests, XRD phase composition tests, and microstructural SEM-EDS tests. The test results indicated that aggressive solution action resulted in decreased flexural strength, however, it did not impact the compressive strength of mortars. A minor impact of chloride ions on the pH of the pore liquid was recorded, while the tests did not show any influence of sulphate ions. Furthermore, aggressive ion concentration decreased in deeper specimen slices. Specimen phase composition testing after chloride ion action indicated the presence of a small amount of Friedel’s salt, while regular sodium chloride crystals were identified in the microscopic image. The performance properties of mortars exposed to the action of aggressive solutions were maintained.

Test Research of Chloride Ion Penetration in Concrete Tunnel Lining Structure

2012 ◽  
Vol 446-449 ◽  
pp. 3155-3159
Author(s):  
Zhong Li ◽  
Yan Peng Zhu ◽  
Xiao Yan Cui
Keyword(s):  
Service Life ◽  
Penetration Depth ◽  
Chloride Ion ◽  
Chloride Content ◽  
Chloride Ions ◽  
Tunnel Lining ◽  
Chloride Ion Penetration ◽  
Lining Structure ◽  
Erosion Environment ◽  
Ion Penetration

Chloride ion diffusion coefficient is an important indicator reflected the concrete durability in chloride erosion environment, and affects the service life of concrete structure directly. By the indoor test of chloride acceleration permeability, the chloride ions diffusivity is studied in the tunnel lining structure, and the variation law of the chloride content is tested with the change of penetration depth of different age specimen. Tests shows, with the increases of the penetration depth, the chloride content decrease gradually and finally tend to the initial chloride content of the specimen. Penetration time has a strong cumulative effect on the internal concentration of chloride ions in concrete, the high or low level of chloride ion concentration have a role of promotion or reduction for the chloride ion penetration in the concrete inside. The results provide an important basis for the predictions of service life of tunnel lining in chloride erosion environment.

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