The Effect of Superplasticizer on Strength and Chloride Permeability of Concrete Containing GGBFS

2013 ◽  
Vol 804 ◽  
pp. 12-16 ◽  
Author(s):  
Shi Yi Zhang ◽  
Ying Fang Fan ◽  
Ning Ning Li
Keyword(s):  
Mechanical Property ◽  
Compressive Strength ◽  
Diffusion Coefficients ◽  
Chloride Ion ◽  
Ion Diffusion ◽  
Chloride Permeability ◽  
Additive Content ◽  
Chloride Ion Penetration ◽  
Chloride Ion Diffusion

The effect of superplasticizer on the mechanical property and chloride permeability of concrete containing GGBFS is investigated in this paper. Compressive and rapid chloride-ion diffusion tests were conducted to determine the axial compressive and chloride-ion diffusion coefficients of GGBFS modified concrete. The tests result indicated that the compressive strength of GGBFS modified concrete with the addition of 2wt. % superplasticizer are further improved at 14 and 28 days. Superplasticizer can significantly enhance the resistance to chloride ion penetration of concrete containing GGBFS with a reasonable additive content at long-term age. The optimum content of superplasticizer is suggested to be 1wt. % to 2wt. % of the cementitous materials.

scholarly journals Bentonite replacing part of cement concrete for resistance to chloride ion attack

2019 ◽  
Vol 136 ◽  
pp. 03011
Author(s):  
Jie Luo ◽  
Chuanchang Li ◽  
Yafei Ma ◽  
Lei Wang
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Ion Diffusion ◽  
Natural Pozzolan ◽  
Cement Production ◽  
Chloride Ion Penetration ◽  
Chloride Migration ◽  
Chloride Ion Diffusion

Bentonite is known as a kind of natural pozzolan that can improve the mechanical properties of cementitious materials and reduce the overall CO2 output of cement production. This study is designed to evaluate the feasibility of using bentonite as a substitute for cement in concrete and analyze the effect of bentonite on resisting chloride ion penetration. The concrete was replaced by equal-quality bentonite for 0%, 5%, 10%, 15% and 20% cement respectively, and the water-cement ratio, fine and coarse aggregate content remained constant. The results indicated that as the bentonite content increased, the compressive strength of the mixes increased first and then decreased. The sample containing 10% bentonite got a higher compressive strength than the other samples. The rapid chloride migration (RCM) tests showed that the samples containing bentonite had better resistance to chloride ion attack than samples without bentonite against chloride, especially the sample containing 10% bentonite. It can be concluded that the concrete with 10% bentonite can improve the resistance to chloride ion diffusion with high compressive strength.

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.

scholarly journals Evaluation of Chloride-Ion Diffusion Characteristics of Wave Power Marine Concrete Structures

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5675
Author(s):  
Changhyuck Lim ◽  
Gyuyong Kim ◽  
Gyeongtae Kim ◽  
Bokyeong Lee ◽  
Youngduck Kim ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Atmospheric Pressure ◽  
Concrete Structures ◽  
Chloride Ion ◽  
Wave Power ◽  
Ion Diffusion ◽  
Chloride Ion Penetration ◽  
Chloride Attack ◽  
Marine Concrete ◽  
Chloride Ion Diffusion

Wave power marine concrete structures generate electrical energy using waves. They are exposed to a multi-deterioration environment because of air and hydrostatic pressure and chloride attack. In this study, the effect of air pressure repeatedly generated by water level change of wave power marine concrete structures on the chloride-ion diffusion of marine concrete was analyzed. The chloride-ion diffusion of wave power marine concrete structures was evaluated. The results show that the air chamber and bypass room, which were subjected to repetitive air pressures caused by water level changes, showed a higher water-soluble chloride-ion content compared to the generator room and docking facility, which were subjected to atmospheric pressure. Field exposure tests and indoor chloride attack tests were performed using fabricated specimens to analyze the effect of pressure on chloride-ion penetration. It was confirmed that Portland blast furnace slag had a greater inhibitory effect on chloride-ion penetration than ordinary Portland cement. The concrete specimens subjected to pressure showed increased capillary pores and micro-cracks. We devised an equation for calculating the diffusion coefficient based on measured data and estimating the diffusion coefficient for the location receiving repeated air pressure by using the diffusion coefficient of the location receiving general atmospheric pressure.

scholarly journals Evaluation of Relationship between Water Absorption and Durability of Concrete Materials

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
S. P. Zhang ◽  
L. Zong
Keyword(s):  
Compressive Strength ◽  
Surface Water ◽  
Water Absorption ◽  
Chloride Ion ◽  
Sulfate Attack ◽  
Ion Diffusion ◽  
Curing Conditions ◽  
Concrete Materials ◽  
Chloride Ion Diffusion ◽  
Durability Of Concrete

Environment has significant effects on the water absorption of concrete materials. This paper presents an experimental study of the influence of water absorption on the durability of concrete materials. A detailed analysis is also presented in order to establish useful relationship between them. Concrete specimens of different water absorption were prepared through different curing conditions, and results indicated that curing condition can significantly affect the surface water absorption. SEM photos also showed that different curing conditions caused different microstructure. After 28-days curing, compressive strength, permeability, sulfate attack, and chloride ion diffusion of concrete samples were investigated. As a result, both of surface sorptivity and internal sorptivity have no clear relationship with compressive strength. Results obtained also showed that only surface water absorption related to the performance of concrete including permeability, sulfate attack, and chloride ion diffusion. In addition, both impermeability and resistance to sulfate attack were linearly associated with surface sorptivity, and both correlation coefficients were not less than 0.9. Furthermore, chloride ion diffusion coefficient has exponent relation to surface water absorption with higher correlation coefficient. However, no apparent relationship was found between internal water absorption and durability like impermeability, resistance to sulfate attack, and chloride ion diffusion.

Variations in the Short- and Long-Term Characteristics of Bridge Concrete Due to Transportation Techniques

2000 ◽  
Vol 1698 (1) ◽  
pp. 36-44
Author(s):  
Nur Yazdani ◽  
Michael Bergin ◽  
Ghulam Mujtaba
Keyword(s):  
Compressive Strength ◽  
Chloride Ion ◽  
Unit Weight ◽  
Concrete Durability ◽  
Long Term Effects ◽  
Chloride Permeability ◽  
Highway Projects ◽  
Air Content ◽  
Before And After

The short-term effects of pumping on concrete are well documented, although the long-term effects on concrete durability are not known. Pumping of concrete is widely used in large highway projects because of its convenience and economy of placement. Both types of effects were studied through collection and testing of 73 concrete samples from the Florida Department of Transportation (FDOT) bridge construction sites before and after pumping. The tests performed were air content, slump, unit weight, compressive strength, rapid chloride permeability, and water permeability. The air content and the slump of concrete decreased by about 1 percent and 13 mm (0.5 in.) on average, respectively, due to pumping. The unit weight and compressive strength of concrete increased by about 24 kg/m3 (1.5 pcf) and 1.83 MPa (266 psi), respectively, due to pumping. Pumping decreased the water and chloride ion permeabilities in the majority of tested samples. Results show that pumping does not have detrimental effects on concrete properties; in fact, in many cases, it results in stronger, denser, and more durable concrete. Results indicate that pumping can be continued with confidence as a means of concrete placement in FDOT projects.

The Effect of Surface Hydrophobation Silane Treatment on Chloride Ion Penetration Resistance for Concrete Structures in Marine Environments

2012 ◽  
Vol 598 ◽  
pp. 524-530
Author(s):  
Hai Cheng Yang ◽  
Zhao Zhong Wang ◽  
Jian Bo Xiong
Keyword(s):  
Convection Zone ◽  
Chloride Concentration ◽  
Chloride Ion ◽  
Concrete Surface ◽  
Ion Diffusion ◽  
Exposure Test ◽  
Wetting And Drying ◽  
Chloride Ion Penetration ◽  
Chloride Ion Diffusion ◽  
Effect Of Surface

Effect of concrete surface hydropobation treatment against chloride penetration have been studied by in-site exposure test. The results show that the silane impregnated layer can prevent the chlorides penetration into the concrete substrate effectively, reduce the apparent chloride ion diffusion coefficient and surface chloride concentration, and improve the service life of concrete structure; and the depth of concrete convection zone can reduce due to silane impregnated layer for concrete in the marine environment of wetting and drying area.

A Study on the Evaluation of Probabilistic Durability Life for RC Structures Deteriorated by Chloride Ion

2007 ◽  
Vol 348-349 ◽  
pp. 417-420
Author(s):  
Dong Seok Kim ◽  
Han Seung Lee ◽  
Seong Min Lee ◽  
Xiao Yong Wang
Keyword(s):  
Diffusion Coefficient ◽  
Concrete Structures ◽  
Prediction Method ◽  
Chloride Ion ◽  
Ion Diffusion ◽  
Rc Structures ◽  
Equivalent Age ◽  
Chloride Ion Penetration ◽  
Reliability Assessments ◽  
Chloride Ion Diffusion

Chloride attacks concrete structures becoming a primary factor that deteriorates the durability of concrete structures. For this reason, research has been conducted on chloride ion penetration and diffusion. This research produced an accurate durability life prediction through reliability assessments and proposes a prediction method for the chloride ion diffusion coefficient of a concrete applied assessment program for reliability. As a result, test materials were fabricated using different admixtures and chloride ion diffusion coefficient was calculated by applying an RCPT test at each equivalent age. Based on these results, reliability prediction formulas were indicated through the reliability analysis for a durability life design using a Montecarlo method. In addition, propriety was verified through comparisons and analysis using the proposed formula with the investigated data for chloride ion diffusion.

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