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 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.

Effect of triethanolamine on the chloride binding capacity of cement paste with a high volume of fly ash

2021 ◽  
pp. 125612
Author(s):  
Yibiao Teng ◽  
Songhui Liu ◽  
Zhaocai Zhang ◽  
Jiangwei Xue ◽  
Xuemao Guan
Keyword(s):  
Fly Ash ◽  
Cement Paste ◽  
Binding Capacity ◽  
High Volume ◽  
Chloride Binding

scholarly journals Layered Double Hydroxides Precursor as Chloride Inhibitor: Synthesis, Characterization, Assessment of Chloride Adsorption Performance

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2537 ◽  
Author(s):  
Lin Chi ◽  
Zheng Wang ◽  
Youfang Zhou ◽  
Shuang Lu ◽  
Yan Yao
Keyword(s):  
Removal Rate ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Chloride Ions ◽  
Ion Removal ◽  
Hydraulic Concrete ◽  
Adsorption Behaviors ◽  
The Stability ◽  
Inhibition Performance ◽  
Double Hydroxides

In this study, the chloride adsorption behaviors of CaAl-Cl LDH precursors with various Ca:Al ratios were investigated. The optimal chloride ion removal rate was 87.06% due to the formation of hydrocalumite. The chloride adsorption products of CaAl-Cl LDH precursors were further characterized by X-ray diffraction analysis and atomic structure analysis, the adsorption mechanism was considered to be co-precipitate process. The chloride adsorption behaviors of cementitious materials blended with CaAl-Cl LDH precursors were further investigated. Leaching test according to Test Code for Hydraulic Concrete (SL352-2006) was performed to testify the stability of chloride ions in the mortar. The results show that more than 98.3% chloride ions were immobilized in cement mortar blended with CaAl-Cl LDH precursor and cannot be easily released again. The inhibition performance of steel in the electrolytes with/without CaAl LDH precursor was investigated by using electrochemical measurements. The results indicate that CaAl LDH precursor can effectively protect the passive film on steel surface by chloride adsorption. Considering the high anion exchange capacities of the LDHs, synthesized chloride adsorbent precursor can be applied as new inhibitors blended in cementitious materials to prevent the chloride-induced deterioration. Moreover, the application of chloride adsorption on CaAl-Cl LDH could also be of interest for the application of seawater blended concrete.

Improving the chloride binding capacity of cement paste by adding nano-Al2O3

2019 ◽  
Vol 195 ◽  
pp. 415-422 ◽  
Author(s):  
Zhiqiang Yang ◽  
Yun Gao ◽  
Song Mu ◽  
Honglei Chang ◽  
Wei Sun ◽  
...  
Keyword(s):  
Cement Paste ◽  
Binding Capacity ◽  
Chloride Binding

Corrosion resistance of steel bar and chloride binding capacity of cementitious materials with internal chloride

2019 ◽  
Vol 139 (3) ◽  
pp. 1903-1914
Author(s):  
Yongmin Yang ◽  
Tongsheng Zhang ◽  
Zhaoheng Li ◽  
Kexin Zhao ◽  
Jiangxiong Wei ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Binding Capacity ◽  
Cementitious Materials ◽  
Chloride Binding ◽  
Steel Bar

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.

scholarly journals THE EFFECT OF THE CALCIUM LEACHING ON CAPACITY FOR CHLORIDE ION BINDING OF THE HARDENED CEMENT PASTE

2013 ◽  
Vol 67 (1) ◽  
pp. 137-143 ◽  
Author(s):  
Kiyofumi KURUMISAWA ◽  
Yuto MURAKAMI ◽  
Kunihiko ISHIGAKI ◽  
Toyoharu NAWA
Keyword(s):  
Cement Paste ◽  
Chloride Ion ◽  
Ion Binding ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
Calcium Leaching

scholarly journals Chloride-Binding Capacity of Portland Cement Paste Blended with Synthesized CA2 (CaO·2Al2O3)

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yunsu Lee ◽  
Mingyun Kim ◽  
Zhengxin Chen ◽  
Hanseung Lee ◽  
Seungmin Lim
Keyword(s):  
Portland Cement ◽  
Cement Paste ◽  
Binding Capacity ◽  
Water Soluble ◽  
Chloride Binding ◽  
X Ray Diffraction ◽  
Total Chloride ◽  
X Ray ◽  
Isotherm Equation ◽  
Portland Cement Paste

A chloride-binding capacity is the major factor to mitigate the ingress of chloride into concrete. This paper presents the chloride-binding capacity of Portland cement paste containing synthesized CA2 (CaO·2Al2O3). The CA2 was synthesized in the high-temperature furnace and characterized by X-ray diffraction for inspecting the purity. The synthesized CA2 was substituted for Portland cement by 0%, 5%, and 10% by weight, and the NaCl solution was used as an internal chloride, which is assumed as a total chloride. The chloride-binding capacity of cement paste was calculated from a water-soluble chloride extraction method by the application of the Langmuir isotherm equation. And the hydration products were analyzed using X-ray diffraction and thermogravimetric analysis. We demonstrate that the CA2 increases an AFm phase in the Portland cement system, and the incorporation of CA2 consequently enhances the chloride-binding capacity of cement paste samples.

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