scholarly journals Concrete with Improved Chloride Binding and Chloride Resistivity by Blended Cements

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Katalin Kopecskó ◽  
György L. Balázs
Keyword(s):  
Binding Capacity ◽  
Experimental Studies ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Ion Binding ◽  
Chloride Binding ◽  
Test Results ◽  
Blended Cements ◽  
Water To Cement Ratio ◽  
Selection Of

Durability and service life of concrete structures can be endangered by chloride ions. Two phenomena help to keep control of chloride effects. On one hand cements are able to bind chloride ions by their aluminate clinker phases or by the clinker substituting materials. On the other hand resistivity of concrete against chloride penetration can be improved by careful selection of concrete constituents and production. Detailed results of two series of extensive experimental studies are presented herein. Chloride ion binding capacity of tested cements in decreasing sequence was the following: (1) CEM III/B 32,5 N-S; (2) CEM III/A 32,5 N; (3) CEM II/B 32,5 R; (4) CEM II/B-M (V-L) 32,5 R; (5) CEM I 42,5 N. Test results indicated that the increasing substitution of clinkers by GGBS improves the chloride resistivity in concrete made with the same water to cement ratio. The application of air entraining agent increases considerably the values of Dnssm. Based on the migration coefficients (Dnssm) the following sequence of efficiency was found (from the best): CEM III/B 32,5 N > CEM V/A (S-V) 32,5 N > CEM III/A 32,5 N > CEM II/B-S 42,5 R > CEM II/A-S 42,5 N > CEM I 42,5 N.

scholarly journals Effect of Fly Ash as Cement Replacement on Chloride Diffusion, Chloride Binding Capacity, and Micro-Properties of Concrete in a Water Soaking Environment

2020 ◽  
Vol 10 (18) ◽  
pp. 6271 ◽  
Author(s):  
Jun Liu ◽  
Jiaying Liu ◽  
Zhenyu Huang ◽  
Jihua Zhu ◽  
Wei Liu ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Fly Ash ◽  
Binding Capacity ◽  
Chloride Ion ◽  
Chloride Content ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Chloride Binding ◽  
Test Results ◽  
New Equation

This paper experimentally studies the effects of fly ash on the diffusion, bonding, and micro-properties of chloride penetration in concrete in a water soaking environment based on the natural diffusion law. Different fly ash replacement ratio of cement in normal concrete was investigated. The effect of fly ash on chloride transportation, diffusion, coefficient, free chloride content, and binding chloride content were quantified, and the concrete porosity and microstructure were also reported through mercury intrusion perimetry and scanning electron microscopy, respectively. It was concluded from the test results that fly ash particles and hydration products (filling and pozzolanic effects) led to the densification of microstructures in concrete. The addition of fly ash greatly reduced the deposition of chloride ions. The chloride ion diffusion coefficient considerably decreased with increasing fly ash replacement, and fly ash benefits the binding of chloride in concrete. Additionally, a new equation is proposed to predict chloride binding capacity based on the test results.

Influence of LDHs on Chloride Ion Binding in Cementitious Materials

2014 ◽  
Vol 599 ◽  
pp. 34-38 ◽  
Author(s):  
Ping Duan ◽  
Zhong He Shui ◽  
Guo Wei Chen
Keyword(s):  
Cement Paste ◽  
Binding Capacity ◽  
Mixing Time ◽  
Reference Sample ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Initial Time ◽  
Ion Binding ◽  
Chloride Binding ◽  
Double Hydroxides

Layered double hydroxides (LDHs) materials could be used in cement and concrete for their ions capturing capacity and to enhance durability of concrete. In this work, properties and chloride binding capacity of different types of LDHs were compared, micro-mechanism of chloride binding of LDHs were analyzed and chloride binding of cement paste incorporating LDHs were investigated. The experimental results show that Mg-Al-NO3 LDHs presents higher chloride ion binding capacity at initial time compared to LDOs calcinated at 500 °C while ion binding capacity of LDHs calms down and LDOs increases with increasing mixing time. Cement paste incorporating LDHs presents higher chloride binding capacity compared with reference sample. All types of LDHs performed beneficial effect on the chloride penetration resistance especially with addition of 1% Mg-Al-NO3 LDOs.

scholarly journals Chloride Binding Capacity and Its Effect on the Microstructure of Mortar Made with Marine Sand

2021 ◽  
Vol 13 (8) ◽  
pp. 4169
Author(s):  
Congtao Sun ◽  
Ming Sun ◽  
Tao Tao ◽  
Feng Qu ◽  
Gongxun Wang ◽  
...  
Keyword(s):  
Binding Capacity ◽  
Chloride Content ◽  
Chloride Ions ◽  
Fine Aggregate ◽  
Chloride Binding ◽  
River Sand ◽  
Total Chloride ◽  
Curing Period ◽  
Marine Sand ◽  
Bound Chloride

Chloride binding capacity and its effect on the microstructure of mortar made with marine sand (MS), washed MS (WMS) and river sand (RS) were investigated in this study. The chloride contents, hydration products, micromorphology and pore structures of mortars were analyzed. The results showed that there was a diffusion trend for chloride ions from the surface of fine aggregate to cement hydrated products. During the whole curing period, the free chloride content in the mortars made by MS and WMS increased firstly, then decreased and stabilized finally with time. However, the total chloride content of three types of mortar hardly changed. The bound chloride content in the mortars made by MS and WMS slightly increased with time, and the bound chloride content included the MS, the WMS and the RS arranged from high to low. C3A·CaCl2·10H2O (Friedel’s salt) was formed at the early age and existed throughout the curing period. Moreover, the volume of fine capillary pore with a size of 10–100 nm increased in the MS and WMS mortar.

Effect of cementation on the small-strain parameters of sands

2001 ◽  
Vol 38 (1) ◽  
pp. 191-199 ◽  
Author(s):  
A L Fernandez ◽  
J C Santamarina
Keyword(s):  
Laboratory Test ◽  
Experimental Studies ◽  
Small Strain ◽  
Test Results ◽  
Loading History ◽  
Viscous Losses ◽  
Laboratory Test Results ◽  
Geotechnical Design ◽  
Selection Of

Natural cementation affects the properties of soils, the interpretation of in situ and laboratory test results, and the selection of criteria for geotechnical design. In this paper, published experimental studies are reviewed, a microscale analysis is presented of the effect of cementation on small-strain stiffness for distinct stress-cementation histories, and the effect of cementation on small-strain velocity and damping is experimentally studied. Observations include the prevailing effects of cementation over effective stress, the coexistence of frictional and viscous losses, and the effects of decementation when the medium is unloaded from the level of confinement prevailing during cementation.Key words: wave velocity, seismic response, stiffness, damping, sampling effects, loading history.

Effect of Stray Current on Chloride Binding Mechanism in Concrete

2012 ◽  
Vol 204-208 ◽  
pp. 3720-3723 ◽  
Author(s):  
Qiao Zhu ◽  
Lin Hua Jiang ◽  
Yi Chen
Keyword(s):  
Chloride Ion ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Chloride Binding ◽  
Stray Current ◽  
Total Chloride ◽  
Binding Rate ◽  
Free Chloride ◽  
The Relationship ◽  
Bound Chloride

In this article, simulation tests of chloride binding were made under the condition of sodium chloride as an internal admixture while loaded with stray current externally. Through the potential titration method, free chloride ion concentration Cf 、 total chloride ion concentration Ct and chloride binding rate RCl were determined. The results show that: With the increase of the strength and action time of the stray current, the number of internal free chloride ions in the cement paste increases while that of the corresponding bound chloride ions reduces significantly, leading to the decrease of chloride binding rate. The relationship between chloride binding rate and the two can be shown as follows respectively:RCl=50.754e(-I/28.258)+42.532、RCl=63.427 e(-T/8.238)+27.325.

scholarly journals The chloride effect in the human embryonic haemoglobins

1995 ◽  
Vol 309 (3) ◽  
pp. 959-962 ◽  
Author(s):  
O Hofmann ◽  
G Carrucan ◽  
N Robson ◽  
T Brittain
Keyword(s):  
Oxygen Affinity ◽  
Chloride Concentration ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Chloride Binding ◽  
Independent Components ◽  
Binding Data ◽  
Chloride Effect ◽  
Allosteric Model

The interactions of the three human embryonic haemoglobins with chloride ions have been investigated. Each of the three embryonic haemoglobins exhibits a unique pattern of oxygen-affinity-dependence on chloride ion concentration. Human embryonic haemoglobin Portland (zeta 2 gamma 2) is found to be completely insensitive to chloride ion concentration. Haemoglobin Gower I (zeta 2 gamma 2) shows a small concentration dependence, whilst haemoglobin Gower II (alpha 2 epsilon 2) exhibits a dependence approaching that of the adult protein. The degree of co-operativity for each protein is essentially chloride concentration independent. The chloride-dependent and -independent components of the alkaline Bohr effects have been measured for each of the embryonic haemoglobins and compared with that of the adult protein. Both the chloride-binding data and the Bohr effect have been analysed in terms of the recently developed allosteric model proposed by Perutz [Perutz, Fermi, Poyart, Pagnier and Kister (1993) J. Mol. Biol. 233, 536-545].

scholarly journals Prediction of Chloride Penetration into Hardening Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Wei-Jie Fan ◽  
Xiao-Yong Wang
Keyword(s):  
Cement Hydration ◽  
Binding Capacity ◽  
Numerical Procedure ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Experimental Investigations ◽  
Hydration Reaction ◽  
Degree Of Hydration ◽  
Chloride Diffusivity ◽  
Chloride Ion Penetration

In marine and coastal environments, penetration of chloride ions is one of the main mechanisms causing concrete reinforcement corrosion. Currently, most of experimental investigations about submerged penetration of chloride ions are started after the four-week standard curing of concrete. The further hydration of cement and reduction of chloride diffusivity during submerged penetration period are ignored. To overcome this weak point, this paper presents a numerical procedure to analyze simultaneously cement hydration reaction and chloride ion penetration process. First, using a cement hydration model, degree of hydration and phase volume fractions of hardening concrete are determined. Second, the dependences of chloride diffusivity and chloride binding capacity on age of concrete are clarified. Third, chloride profiles in hardening concrete are calculated. The proposed numerical procedure is verified by using chloride submerged penetration test results of concrete with different mixing proportions.

scholarly journals Diffusion Behavior of Chloride Ions in Concrete Box Girder under the Influence of Load and Carbonation

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2117
Author(s):  
Yinglong Liu ◽  
Pengzhen Lin ◽  
Junjun Ma
Keyword(s):  
Coupling Effect ◽  
Chloride Concentration ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Scale Model ◽  
Test Results ◽  
Box Girder ◽  
Concrete Box Girder ◽  
The Difference

In order to study the durability degradation characteristics of concrete box girder under load and carbonation and chloride ion erosion, a scale model of concrete box girder was made for experimental research. According to the test results, the diffusion characteristics of chloride ions in the concrete box girder under the coupling effect of load and carbon dioxide were analyzed. By revising the calculation formula of the existing chloride ion concentration considering multiple factors, a calculation model of chloride ion concentration considering the influence of carbonation was proposed, and the test results were verified. The results show that the chloride concentration of the box girder on the same cross section is non-uniformly distributed due to the shear lag effect and the spatial structure. After considering the effect of carbonation, the difference rate of the improved model proposed in this paper is generally within 10%. Compared with the original model, the difference rate is reduced by a maximum of 19%.

scholarly journals Investigation on the transport properties of chlorides in concrete II Numerical simulation

2018 ◽  
Vol 199 ◽  
pp. 02014 ◽  
Author(s):  
TIAN Ye ◽  
JIN Xianyu ◽  
JIN Nanguo
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Transmission Model ◽  
Test Results ◽  
Surface Scanning ◽  
Parallel Transmission ◽  
Transmission Process ◽  
Chloride Ions Diffusion

The chloride ions diffusion in concrete is an important problem inducing the corrosion of reinforcement under marine environment. Based on a parallel transmission model, the diffusion coefficient of chloride ions in ITZ was determined. Thereafter, the measured parameters of ITZ were integrated into a numerical model to simulate the chloride ions diffusion and the reliability of the model was verified by comparing the numerical simulation with the surface scanning results collected from the electron microprobe. The test results show that if the concrete is taken as a threephase composites, the numerical model can reflect the real transmission process of chloride ion more accurately.

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