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.

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.

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 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.

Modeling of Material Parameters of Marine Concrete for Service Life Prediction

2007 ◽  
Vol 348-349 ◽  
pp. 753-756 ◽  
Author(s):  
In Seok Yoon
Keyword(s):  
Life Prediction ◽  
Binding Capacity ◽  
Chloride Content ◽  
Critical Threshold ◽  
Chloride Binding ◽  
Material Parameters ◽  
Chloride Diffusivity ◽  
Durability Design ◽  
Critical Content ◽  
Marine Concrete

It is a prerequisite to formulate material parameters affecting chloride penetration into concrete. This paper is focused on defining intrinsic parameters of concrete, linking a theoretical solution for durability design in submerged concrete under marine environment. Material parameters, such as surface chloride content, chloride diffusivity, critical threshold critical content, chloride binding capacity are formulated.

Chloride Binding of Self-Compacting Concrete with Different Crack Depths under Electric Migration Test

2011 ◽  
Vol 105-107 ◽  
pp. 957-960
Author(s):  
Song Mu ◽  
Bao Guo Ma ◽  
Geert de Schutter ◽  
Shou Wei Jian
Keyword(s):  
Crack Depth ◽  
Chloride Content ◽  
Chloride Ions ◽  
Test Method ◽  
Cement Matrix ◽  
Chloride Binding ◽  
Migration Test ◽  
Cracked Concrete ◽  
Chloride Migration ◽  
Binding Isotherms

Cracks can form a shortcut for transport of chloride ions in concrete structure, and provide more opportunities for chloride ions to contact and bind with cement matrix. Following the NT BUILD 492 chloride migration test method, chloride content were determined on cracked concrete samples which were prepared by artificial crack method. The results shows crack depth increased from 0 mm to 31.4 mm almost did not exert pronounced effects on chloride binding of concrete under the migration test.Besides, the binding parameter of linear binding isotherms almost did not change.

scholarly journals A Study on Dredged Sea Sand as an Optimum Replacement for Fine Aggregate in Concrete

2018 ◽  
Vol 7 (1) ◽  
pp. 1-6
Author(s):  
R. Manigandan .
Keyword(s):  
Chemical Properties ◽  
Chloride Content ◽  
Organic Content ◽  
Resistance Test ◽  
Sieve Analysis ◽  
Fine Aggregate ◽  
Atmospheric Conditions ◽  
River Sand ◽  
Sea Bed ◽  
Sea Sand

This paper deals with the study and feasibility on utilization of dredged sea sand by conducting various experiments on physical properties like sieve analysis, gap grading. Chemical properties like percentage of organic content, chloride content, sulfur content, presence of deleterious material and volatile solids in dredged sea sand have been determined. The experiments like rapid chloride penetration test, water absorption test, alkalinity test, accelerated corrosion test, sulphur resistance test, acid resistance test, and sorptivity. Durability and strength of concrete have been studied by considering various properties of fine aggregate. The mix design have been done for M30 grade of concrete and the percentage of replacements 25%, 50%, 75%, and 100% of M-Sand (Manufacture Sand) of concrete specimen for all the experiments is considered. As we all know our current scenario of increase in demand of fine aggregate leads to scarcity of river sand. This has increased in research on dredged sea sand as a fine aggregate in concrete to reduce the demand on fine aggregate in construction industries. Comparative study of M-sand, river sand and dredged sea sand has been done. The dredged sand which is used for the study and testing is dredged to increase the sea bed depth of Ennor port for the accessibility of mother ship, it was collected from the coastal areas of Ennore Port (Kamarajar Port) and subjected to rain, and atmospheric conditions for a year.

scholarly journals Durability studies on ready mix concrete using mineral admixtures and manufactured sand

2021 ◽  
Author(s):  
Jagadish Vengala ◽  
◽  
K Ramesh ◽  
Manjunath M ◽  
Manish S Dharek ◽  
...  
Keyword(s):  
Fast Track ◽  
Chloride Ions ◽  
Experimental Results ◽  
Mineral Admixtures ◽  
Crushed Rock ◽  
Fine Aggregate ◽  
River Sand ◽  
Manufactured Sand ◽  
Strength And Durability ◽  
Ready Mix Concrete

To meet the intensifying demand of fine aggregate in construction sector, manufactured sand has become a viable alternative to the river sand. Ready mix concrete (RMC) is playing vital role in fast-track construction particularly in Tire-II cities in India. The strength and durability concerns about using 100% manufactured sand along with mineral admixtures in RMC plant needs to be addressed through suitable experimental demonstrations. This research gives the experimental results on strength and durability studies of concrete carried out on samples obtained from RMC Plant by making use of manufactured sand containing (50% of crushed sand and 50% of the crushed rock fines) as replacement for natural sand. Trials on partial replacing cement with fly ash content of 33% and GGBS of 40% has also been carried out. Compressive and split-tensile strength studies were conducted on cubes (150mmx150mmx150mm) and cylinders (150mmx300mm) at 7, 14 & 28 days of curing. Non-Destructive tests such as Ultra Sonic Pulse Velocity (UPV) and rebound hammer tests were conducted to assess the quality of these mixes. Durability tests were conducted and comparison of the % of loss in mass and % of loss in strength for concrete samples subjected to acid attack, sulphate attack, alkaline attack tests were also carried out. Rapid chloride permeability test (RCPT) was conducted to check the concrete resistance against chloride ions penetration. The experimental results revealed that the use of 100% manufactured sand along with mineral admixtures in producing ready mix concrete is a good choice in view of the non-availability of river sand to meet the demands of fast-track construction projects.

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.

Performance of Chloride Binding by Aluminate Hydrates in Cement-Based Composite Materials

2012 ◽  
Vol 583 ◽  
pp. 211-214
Author(s):  
Mi Feng Gou ◽  
Xue Mao Guan
Keyword(s):  
Composite Materials ◽  
Chemical Interaction ◽  
Binding Capacity ◽  
Freundlich Isotherm ◽  
Water Soluble ◽  
Chloride Binding ◽  
Test Results ◽  
X Ray Diffraction ◽  
Total Chloride ◽  
Free Chloride

The chloride binding capacity of aluminate hydrates in cement-based composite materials is investigated. The total chloride contents and free chloride contents were analyzed by acid-soluble method and water-soluble method. The chemical interaction of chloride with the hydrates of aluminate phases in cement was also studied by X-ray diffraction. Test results show that the monosulfate hydrate has chloride binding capacities, whereas ettringite has no capacity to bind chloride. The chloride binding by monosulfate hydrate is attributed to the formation of Friedel’s salt and Kuzel’s salt by the ion exchange of SO42- with Cl- and the nonlinear relationship can be represented best by a Freundlich isotherm.

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