Cloride [sic] ion diffusion in low water-to-solid cement pastes

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Division of Engineering, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Supt. of Docs., U.S. G.P.O. [distributor] , Washington, DC
Portland cement -- Corrosion., Ions -- Scattering., Chlorides -- Diffusion
Other titlesChloride ion diffusion in low water-to-solid cement pastes.
Statementprepared by J.R. Clifton ... [et al.].
SeriesNISTIR -- 4549.
ContributionsClifton, James R., U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research. Division of Engineering., National Institute of Standards and Technology (U.S.)
The Physical Object
FormatMicroform
Paginationvi, 24 p.
ID Numbers
Open LibraryOL15376722M

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The Combining of Sodium Chloride and Calcium Chloride by a Number of Different Hardened Cement Pastes, Cement and Concrete Research, Vol. 8,Goto, S., and Roy, D.M., Diffusion of Ions Through Hardened Cement Pastes, Cement and Concrete Research, Vol. 11,Get this from a library. Cloride [sic] ion diffusion in low water-to-solid cement pastes.

[James R Clifton; U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research. Division of Engineering.; National Institute of Standards and Technology (U.S.);]. The diffusion of chloride ions in neat cement pastes and mortars made with and without a limestone filler was investigated.

In order to study the effect of the limestone filler, all mixtures were prepared at a fixed water cement ratio (0,55). Test results indicate that the addition of a limestone filler reduces the diffusion coefficient of chloride by: diffusion and advection. Diffusion occurs under a concentration gradient, whereas advection is related to transport of substances by moving water under a pressure head.

For the sa turated condition, diffusion is the dominant mechanism for chloride ingress. So we only consider the diffusion of chloride ions in cracked concrete.

The diffusion of cesium or chloride ions was retarded significantly through the use of slag blending in pastes. The porosity was lower and pore structure was finer in the case of the blended cement, which is considered to be the primary reason for the beneficial effect on by: 7. Steady state chloride diffusion through hardened paste was determined using a test originally developed by Hansson and Berke.

Slices of the hardened paste, approximately 3 mm thick were cut from cylindrical specimens after curing for 56 days in saturated Ca(OH) 2. These were glued to the neck of a plastic bottle in the bottom of which a hole.

Cloride ion diffusion in low water-to-solid cement pastes. Diffusion coefficients of water to solids ratio (w/s) hydrated portland cement paste specimens were measured using a conventional.

Details Cloride [sic] ion diffusion in low water-to-solid cement pastes FB2

A rapid chloride ion diffusion coefficient measurement (RCM) was used in this study. The influence of water-cement ratios ofand at various ages (3, 7, 14, 28 and 56 days) on chloride ion diffusion coefficient of the concretes and pastes was studied and analyzed.

The results show that, with the increase of curing ages, the chloride ion diffusion coefficient of different water. The interdiffusion of l− and Cl− ions and the tracer diffusion of Cs+ ions in watersaturated Ordinary Portland Cement have been measured at 30° C as a function of water/ cement ratio at fabrication.

The diffusion was strongly influenced by the water/cement ratio in an approximately exponential manner and the Cs+ ions were significantly less mobile than the other ions. Accelerated migration tests which are commonly used to measure chloride diffusion in ordinary cement-based materials cannot be directly applied to composite with very low.

The corrosion of steel in concrete is mainly due to the chemical reaction between the chloride ions and iron ions. Indeed, this is a serious threaten for reinforced concrete structure, especially. Zheng Chen, Liyun Wu, Vivek Bindiganavile, Chaofan Yi, Coupled models to describe the combined diffusion-reaction behaviour of chloride and sulphate ions in cement-based systems, Construction and Building Materials, /ldmat,(), ().

Nuclear magnetic resonance (NMR) spectroscopy was employed to evaluate the effects of chloride ion diffusion on the chemical environment of hydrated cement paste and concrete.

Al 27 magic angle spinning NMR spectra were obtained at different depths from the surface (surface, 3 mm, and 6 mm) exposed to chloride ion solution after 1 month.

1 Determination of the concrete chloride diffusion coefficient based on an electrochemical test and an optimization model Juan Lizarazo-Marriagaa, Peter Claisseb a,b Departamento de Ingeniería Civil, Universidad Nacional, Bogotá, Colombia.

[email protected] b Materials Applied Research Group, Coventry University COV 5FB, [email protected] the type of cement, water-to-cement ratio, cement content, etc.), there are no guidelines on the chloride concentration in the soil and its influence on reinforcement corrosion.

While some information is available on the chloride threshold for corrosion of steel in concrete, data are lacking on the effect of chloride concentration in soil on. Concrete is composed of cement, aggregate and paste interfacial z41, the larger the aggregate, the smaller the diffusion coefficient.

Increasing or decreasing diffusion coefficient is a traditional method for protecting concr 43, 44, Actually, this method is a “mass diffusion shielding”, just like electrostatic and. This paper discusses the properties of chloride ion diffusion of saturated concrete subjected to salt attack under high temperature conditions.

Immersion tests were conducted for various concrete specimens of plain and fly-ash concrete with three values of waterbinder ratio (W/B=40, 50, 60%) in % NaCl solution, which were controlled at four.

Description Cloride [sic] ion diffusion in low water-to-solid cement pastes FB2

The diffusion of chloride ions into concrete is largely dependent on permeability, which is governed by porosity and pore size distribution [2,3,4].Furthermore, hydration products in concrete can physically or chemically adsorb chloride ions, which is called the chloride binding capacity of concrete [5,6,7,8].Therefore, it is important to consider the development of hydration products to.

Ion Chromatography (IC) Introduction Ion chromatography (IC) is well established as a routine technique for the determination of ionic analytes in environmental samples such as natural waters, tap water, drinking water, and soil. In fact, one of the earliest applications of IC. An attempt is made to replace partially GGBS for cement in concrete of M20 & M25 grades and study its Chloride diffusion.

GGBS is replaced for cement in the level of 10%, 20%, 30%, 40%, 50% and 60%. The study results showed that, with the increase in percentage of GGBS, the Chloride diffusion of concrete decreases.

cent replacement by weight of Type I cement. In addition one blast furnace lag cement containing 60 percent granu­ lated blast furnace slag, wa u. A and-to-cement ratio of 2. 75 was used for mortar specimens, whereas a cement content of kg/m3 wa used in the reinforced concrete.

pecimen used for evaluation of. teel c rro ion. @article{osti_, title = {Diffusion in cementitious materials. 2: Further investigations of chloride and oxygen diffusion in well-cured OPC and OPC/30%PFA pastes}, author = {Ngala, V T and Page, C L and Parrott, L J and Yu, S W}, abstractNote = {Steady-state diffusion of dissolved oxygen and chloride ions in hydrated OPC and OPC/30%PFA pastes, hydrated for 2 weeks at 20 C and 10 weeks at.

The chloride diffusion coefficient of concrete plays an essential role in the durability assessment and design of concrete structures built in chloride-laden environments.

The purpose of this paper is to present an effective medium method (EMM) for evaluating the chloride diffusion coefficient of mature fly ash cement paste. In this method, a numerical method is used to estimate the degrees of.

Determination of diffusion coefficient of chloride in concrete using Warburg diffusion coefficient R. Vedalakshmia,*, V. Saraswathya, Ha-Won Songb, N. Palaniswamya a Corrosion Protection Division, Central Electrochemical Research Institute, Alagappapuram, Karaikudi, Tamil NaduIndia bSchool of Civil Engineering, Yonsei University, SeoulRepublic of Korea.

Nuclear magnetic resonance (NMR) spectroscopy was employed to evaluate the effects of chloride ion diffusion on the chemical environment of hydrated cement paste and concrete.

Al27 magic angle spinning NMR spectra were obtained at different depths from the surface (surface, 3 mm, and 6 mm) exposed to chloride ion solution after 1 month. Chloride Ion Diffusion. Forty-two hours before the start of the test, a cylinder was removed from the curing water and allowed to dry for 30 minutes.

The cylinder was brushed and cleaned with a compressed air jet, then placed in a x mm cylindrical steel mold which was specially machined to form specimens that would fit tightly in the.

A mathematical model of ion diffusion under the action of a constant electric field was established, and the exact analytical solution of the differential equat The chloride diffusivities in cement pastes and mortars with various water-cement ratios were determined by the method proposed in this paper as well as the conventional diffusion.

chloride ion in a sample of concrete, including bound in the solid phases and free chlorides in the pore solution. Free chloride content:Is the amount of chloride ion in the pore solution as obtained by squeezing con-crete samples at high pressures.

Water soluble chloride content:Is the amount of chloride ion in a sample of concrete which can be. Diffusion of Chloride Ions in the Pastes and Mortars Containing Ground Granulated Blast Furnace Slag The progress of corrosion was the most evident in the presence of Mg2+ ion, the slow est corrosion was observed in the presence of sodium.

Ushiyama H. and Goto S., Diffusion of Various Ions in Hardened Portland Cement Paste, 6th ICCC. cement paste. Cement paste can be considered as isotropic material,D1paste paste=D, with the diffusion coefficient Dpaste and the second-order unity tensor 1.

Dpaste is commonly determined by diffusion-cell tests, where two cells, filled with solutions characterized by different salt concentrations, are separated by a cylindrical. However, the chloride penetration reaches low depths for the concrete class used.

Observed data have raised suspicions as to the effect of moisture content on the diffusion of chlorides. A test method was developed to assess the changes in the chloride diffusion coefficient with changes in moisture content in cement paste.Mortars of two water-to-cement ratios and three sand volume fractions were cast together with pastes and tested at degrees of hydration ranging from 45 to 70%.

An electrically-accelerated concentration cell test was used to determine the coefficient of chloride ion diffusion while a .This paper examines chloride diffusion and wicking in concrete with varying water-to-cement ratios (w/c) and varying cement replacement levels by fly ash and slag.

The influence of salt type (NaCl and MgCl 2) on chloride transport is examined. The chloride binding capacity is similar for the cement paste .