scholarly journals Variation in Service Life on RC Structure According to Concrete Binder Type

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5430
Author(s):  
JangHyun Park ◽  
JinHo Park ◽  
MyeongGyu Jung
Keyword(s):  
Service Life ◽  
Chloride Ion ◽  
Chloride Content ◽  
Reinforcing Bars ◽  
Ion Diffusion ◽  
Rc Structure ◽  
Binder Type ◽  
Chlorine Ions ◽  
Ph Level ◽  
Chloride Ion Diffusion

When an additive is used to replace a certain amount of cement, a concrete pore structure becomes dense. Thus, it results in inhibiting the penetration of chlorine ions and suppressing corrosion of reinforcing bars. However, the pH level of the concrete decreases, and it deteriorates the performance of the passive film formed on the surface of the rebars embedded in the concrete. Therefore, in this study, the service lives of reinforced concrete containing different types of concrete binders were predicted and compared. The chloride ion diffusion coefficients of concretes with various binders were measured, and the critical chloride content of the rebar was assessed by the real-time monitoring on the corrosion initiation time of the rebar embedded in concrete. Moreover, Fick’s 2nd law was applied to predict when the chloride content at the 40 mm depth of cover reached the critical chloride content based on the chloride ion diffusion coefficient. It was observed that the service life of S6 (OPC 40% + GGBFS 60%) was the highest, followed by TBC (OPC 40% + GGBFS 40% + FA 20%), S3 (OPC 70% + GGBFS 30%), and OPC (OPC 100%).

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.

Evaluation of the Properties of Polyaspartic Polyurea Coated Concrete Subjected to the Co-Action of Freeze-Thaw Cycles and NaCl Solution Immersion

2011 ◽  
Vol 689 ◽  
pp. 336-342 ◽  
Author(s):  
Wei Bo Huang ◽  
Xu Dong Liu ◽  
Ping Lu ◽  
Jing Zhang
Keyword(s):  
Chloride Ion ◽  
Chloride Content ◽  
Degradation Process ◽  
Test Results ◽  
Nacl Solution ◽  
Ion Diffusion ◽  
Surface Protection ◽  
Freeze Thaw ◽  
Protection Coating ◽  
Chloride Ion Diffusion

The deterioration of coated concrete subjected to co-action of freeze-thaw cycles-NaCl solution immersion double factors exposure was investigated in this study. Adhesion, chloride content and resistance of chloride ion diffusivity of two types of polyaspartic ester polyurea coated concrete were analyzed. Test results showed that the adhesion of QF-1 (PAE-b-H12MDI prepolymer H66) and QF-2 (PAE-b-H12MDI prepolymer H62) coated concrete reduced about 5% respectively which kept excellent under the double factors exposure after 200, 300 days and 25, 50 times of cycles. The degradation process of coated concrete simultaneously exposed to co-action exposure was significantly accelerated. In co-action exposure tests, the average chloride ion content of coated concrete increased about 33% and 87% after 25 and 50 times of cycles compared with single NaCl solution immersion exposure; the chloride ion diffusion coefficient of concrete substrate increased with the increase of exposure time and freeze-thaw cycles. Freeze-thaw cycles results showed a severe influence on chloride ion diffusion and permeation of surface protection coating of concrete. Research also showed that the chloride ion diffusion of coated concrete subjected to the co-action of freeze-thaw cycles-NaCl solution was coincided with the Fick’s second law.

Effect of rust inhibitors and surface strengthening materials on service life of marine RC structures

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Haiwei Zhu ◽  
Hongfa Yu ◽  
Haiyan Ma ◽  
Bo Da ◽  
Qiquan Mei
Keyword(s):  
Service Life ◽  
Chloride Ion ◽  
Life Extension ◽  
Marine Environments ◽  
Ion Diffusion ◽  
Content Type ◽  
Rc Structures ◽  
Surface Strengthening ◽  
Service Life Extension ◽  
Chloride Ion Diffusion

Purpose The purpose of this paper is to compare the effect of rust inhibitors and surface strengthening materials on the service life of RC structures in tropical marine environments and ultimately to provide basis and recommendations for the durability design of reinforced concrete (RC) structures. Design/methodology/approach Slag concrete specimens mixed with four kinds of rust inhibitors and coated with four kinds of surface strengthening materials were corroded by seawater exposure for 365 days, and the key parameters of chloride ion diffusion were obtained by testing. Then a new service life prediction model, based on the modified model for chloride ion diffusion and reliability theory, was applied to analyze the effect of rust inhibitors and surface strengthening materials on the service life of RC structures in tropical marine environments. Findings Rust inhibitors and surface strengthening materials can effectively extend the service life of RC structures through different effects on chloride ion diffusion behavior. The effects of rust inhibitors and surface strengthening materials on the service life extension of RC structures adhered to the following trend: silane material > cement-based permeable crystalline waterproof material > hydrophobic plug compound > spray polyurea elastomer > water-based permeable crystalline waterproof material > calcium nitrite > preservative > amino-alcohol composite. Originality/value Using a new method for predicting the service life of RC structures, the attenuation law of the service life of RC structures under the action of rust inhibitors and surface strengthening materials in tropical marine environments is obtained.

Modeling of Chloride Ion Diffusion in Concrete under Fatigue Loading

2018 ◽  
Vol 23 (1) ◽  
pp. 287-294 ◽  
Author(s):  
Tao Yang ◽  
Bowen Guan ◽  
Guoqiang Liu ◽  
Yanshun Jia
Keyword(s):  
Chloride Ion ◽  
Fatigue Loading ◽  
Ion Diffusion ◽  
Chloride Ion Diffusion

EFFECT OF CRUMB RUBBER ON CONCRETE STRENGTH AND CHLORIDE ION PENETRATION RESISTANCE

2015 ◽  
Vol 77 (32) ◽  
Author(s):  
Nurazuwa Md Noor ◽  
H. Hamada ◽  
Y. Sagawa ◽  
D. Yamamoto
Keyword(s):  
Structural Strength ◽  
Salt Water ◽  
Chloride Ion ◽  
Crumb Rubber ◽  
Rubberized Concrete ◽  
Migration Test ◽  
Ion Diffusion ◽  
Steady State Condition ◽  
Chloride Ion Penetration ◽  
Chloride Ion Diffusion

This paper present the effect of crumb rubber on its ability to produce concrete with structural strength when it was used directly from the plant without any treatment process. Crumb rubber was added as fine aggregates at 0%, 10%, 15% and 20% of sand volume meanwhile silica fume was added at 10% by cement weight. Three main series of concrete namely rubberized concrete with water-to-cement ratio of 50% and 35% was design and development of compressive strength was observed from day 7 until 91 days. Also, effectiveness of crumb rubber under flexural strength and splitting tensile strength was studied at 28 days curing age. Effect of crumb rubber on durability performance was done on chloride ion penetration resistance performance by migration test and by immersion in salt water. Chloride ion diffusion in rubberized concrete by migration test was carried out under steady state condition using effective diffusion coefficient, De meanwhile, immersion test in salt water was conducted under non-steady state condition using apparent diffusion coefficient, Da. Results showed that compressive strength was decrease with the increasing of crumb rubber in the mixture.  Even though the strength were reducing with the inclusion of crumb rubber, the reduction were less than 50% and it achieved acceptable structural strength. Chloride transport characteristics were improved by increasing amount of CR and rubberized concrete with w/c = 0.35 gave better resistance against chloride ion compared to w/c = 0.50 with more than 50% difference. Silica fume provide slightly strength increment compared to normal rubberized concrete and the same behavior was observed during chloride ion diffusion test.

Models for Chloride Ion Diffusion in Archaeological Iron

2001 ◽  
Vol 46 (2) ◽  
pp. 109-120
Author(s):  
L.S. Selwyn ◽  
W.R. Mckinnon ◽  
V. Argyropoulos
Keyword(s):  
Chloride Ion ◽  
Ion Diffusion ◽  
Archaeological Iron ◽  
Chloride Ion Diffusion

Durability of Self-Compacting Concrete

2011 ◽  
Vol 324 ◽  
pp. 340-343
Author(s):  
Abdelaziz Benmarce ◽  
Hocine Boudjehem ◽  
Robila Bendjhaiche
Keyword(s):  
Oxygen Permeability ◽  
Chloride Ion ◽  
Chemical Characteristics ◽  
Capillary Absorption ◽  
Ion Diffusion ◽  
Self Compacting Concrete ◽  
Fresh State ◽  
Physical And Chemical ◽  
Transfer Properties ◽  
Chloride Ion Diffusion

Abstract. Self compacting concrete (SCC) seem to be a very promising materials for construction thanks to their properties in a fresh state. Studying of the influence of the parameters of specific designed mixes to their mechanical, physical and chemical characteristics in a state hardened is an important stage so that it can be useful for new-to-the-field researchers and designers (worldwide) beginning studies and work involving self compacting concrete. The objective of this research is to study the durability of self compacting concrete. The durability of concrete depends very much on the porosity; the latter determines the intensity of interactions with aggressive agents. The pores inside of concrete facilitate the process of damage, which began generally on the surface. We are interested to measure the porosity of concrete on five SCC with different compositions (w/c, additives) and vibrated concrete to highlight the influence of the latter on the porosity, thereafter on the compressive strength and the transfer properties (oxygen permeability, chloride ion diffusion, capillary absorption).

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