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.

scholarly journals REDUCING CONCRETE PERMEABILITY BY USING NATURAL POZZOLANS AND REDUCED AGGREGATE-TO-PASTERATIO

2015 ◽  
Vol 21 (2) ◽  
pp. 165-176 ◽  
Author(s):  
Fernando Bustos ◽  
Patricia Martinez ◽  
Carlos Videla ◽  
Mauricio Lopez
Keyword(s):  
Cement Content ◽  
Blended Cement ◽  
Chloride Ion ◽  
Air Permeability ◽  
Ion Diffusion ◽  
Natural Pozzolans ◽  
Concrete Permeability ◽  
Cementing Material ◽  
Chloride Ion Diffusion ◽  
Durability Of Concrete

Improved durability of concrete is mainly achieved with low-permeability. Permeability depends on permeability of the bulk cement paste (CP) and that of its interfacial transition zone (ITZ). Even though permeability of CP is well understood and can be adequately controlled, permeability of ITZ is not well understood yet. This paper shows that minimizing permeability of concrete requires minimizing permeability of CP by using a supplementary cementing material (SCM) such as natural pozzolans (NP) and minimizing ITZ by reducing aggregate content until maximum cement content. This was done by comparing performance of concrete made with ordinary Portland cement (OPC) and blended cement (OPC+NP) at the same w/b, and by comparing performance of concrete with different amount of ITZ at the same w/b. All of this was performed through testing of mechanical properties, air permeability, sorptivity, chloride ion diffusion, and aggregate specific surface. Results show that NP reduced air permeability by 84% and chloride ion diffusion by 66%, but increased sorptivity up to 140%. ITZ has an important effect in all properties; especially in air permeability where sensitive reduction of more than a 90% was achieved. ITZ effect seems to be as important as using SCMs in improving durability of concrete.

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.

The Research of Influence on the Freezing Resistance and the Permeation Resistance of Concrete With Spraying Silane

2014 ◽  
Vol 629-630 ◽  
pp. 213-217
Author(s):  
Xin Ge ◽  
Xian Hui Song ◽  
Yong Ge ◽  
Xiao Ping Cai
Keyword(s):  
Diffusion Coefficient ◽  
Water Absorption ◽  
Penetration Depth ◽  
Frost Resistance ◽  
Absorption Rate ◽  
Chloride Ion ◽  
Ion Diffusion ◽  
Water Absorption Rate ◽  
Liquid Absorption ◽  
Chloride Ion Diffusion

Silane, as an extremely hydrophobic material, changes concrete surface from hydrophilic state to hydrophobic state by spraying on the surface of concrete. It has the ability to block the external corrosive medium to improve the durability of concrete. Three types of strength grade of concrete (C30, C40, C50) were designed, after spraying with silane on the surface of concrete, to measure the penetration depth of silane and the influence on water-absorption rate, liquid-absorption rate, chloride ion diffusion coefficient and salt frost resistance. The test result shows that: by spraying silane on the surface of concrete,the one hour water-absorption rate of concrete was reduced by more than 98%, the 48 hours water-absorption rate was cut down above 91%, and the 48 hours liquid-absorption (3% NaCl solution) rate was decreased above 94%. The penetration depth for C30 and C50 has the maximum value (6.3mm) and minimum value (3.9mm) respectively. Absorption reduction rate of chloride ion overall was decreased by above 93%, and chloride ion diffusion coefficient was reduced by 42% ~ 48%. The freeze-thaw resistance was improved by 5 times. Key words: silane, the salt frost resistance, liquid-absorption rate, chloride ion diffusion coefficient

scholarly journals Some Durability Aspects of Ambient Cured Bottom Ash Geopolymer Concrete

2017 ◽  
Vol 63 (3) ◽  
pp. 99-114 ◽  
Author(s):  
R. Saravanakumar ◽  
V. Revathi
Keyword(s):  
Water Absorption ◽  
Bottom Ash ◽  
Chloride Ion ◽  
Passive Layer ◽  
Geopolymer Concrete ◽  
Test Results ◽  
Ion Diffusion ◽  
Conventional Concrete ◽  
Accelerated Corrosion ◽  
Chloride Ion Diffusion

Abstract The present study examines some durability aspects of ambient cured bottom ash geopolymer concrete (BA GPC) due to accelerated corrosion, sorptivity, and water absorption. The bottom ash geopolymer concrete was prepared with sodium based alkaline activators under ambient curing temperatures. The sodium hydroxide used concentration was 8M. The performance of BA GPC was compared with conventional concrete. The test results indicate that BA GPC developes a strong passive layer against chloride ion diffusion and provides better protection against corrosion. Both the initial and final rates of water absorption of BA GPC were about two times less than those of conventional concrete. The BA GPC significantly enhanced performance over equivalent grade conventional concrete (CC).

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.

Permeability of Anti-Chloride Ion of Fly Ash Recycled Concrete

2011 ◽  
Vol 317-319 ◽  
pp. 544-547
Author(s):  
Ai Jiu Chen ◽  
Jing Wang ◽  
Zhan Fang Ge ◽  
Ming Wu
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Coarse Aggregate ◽  
Chloride Ion ◽  
Reducing Agent ◽  
Polypropylene Fibre ◽  
Recycled Concrete ◽  
Ion Diffusion ◽  
The North ◽  
Chloride Ion Diffusion

Adding fly ash to recycled concrete with super-substitute technique, comparing the 28d strength of fly ash recycled concrete(FARC) with the 28d strength of ordinary recycled concrete(ORC), the compressive strength of fly ash recycled concrete slightly decreased with the increase of the fly ash and the admixture of renewable aggregate. Along with the increase of mixing amount of the air entraining and water-reducing agent, the compressive strength of fly ash recycled concrete tends to reduce. The order of the factors that affect the chloride ion diffusion coefficient of recycled concrete is fly ash admixture→mixing amount of the air entraining and water-reducing agent→admixture of recycled coarse aggregate→polypropylene fibre admixture, which provides a basis for the application of recycled concrete engineering in the environment which is affected by chlorine salt in the north frigid area .

scholarly journals Effect of Curing Condition on Resistance to Chloride Ingress in Concrete Using Ground Granulated Blast Furnace Slag

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3233 ◽  
Author(s):  
JangHyun Park ◽  
Cheol Park ◽  
SungHyung Joh ◽  
HanSeung Lee
Keyword(s):  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Blast Furnace Slag ◽  
Chloride Ion ◽  
Ion Diffusion ◽  
Concrete Compressive Strength ◽  
Replacement Ratio ◽  
Granulated Blast Furnace Slag ◽  
Chloride Ion Diffusion ◽  
Furnace Slag

Changes in the salt attack resistance of concrete using ground granulated blast furnace slag (GGBFS) were examined based on different curing conditions. These conditions were divided into air and underwater curing. Three concrete mixes with GGBFS replacement ratios of 0% (control group), 30% and 60% were fabricated. Then, evaluation of concrete compressive strength, evaluation of chloride ion diffusion coefficient and electrochemical impedance spectroscopy (EIS) were performed. As the GGBFS replacement ratio increased, the concrete compressive strength of the air cured specimens decreased compared to the underwater cured specimens. With respect to the chloride ion diffusion coefficient measurements, the coefficient decreased as the GGBFS replacement ratio increased. However, the diffusion coefficient of the air cured specimen relative to the underwater cured ones increased up to two times. The EIS results showed that as the GGBFS replacement ratio increased, |Z| increased in every frequency range. However, the |Z| of the air cured specimen was lower than the underwater cured one. This showed the same tendency as the evaluation results of the chloride ion diffusion coefficient.

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.

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