CN110987989A - Method for obtaining content of multiple phase-bound chloride ions in cement paste - Google Patents
Method for obtaining content of multiple phase-bound chloride ions in cement paste Download PDFInfo
- Publication number
- CN110987989A CN110987989A CN201911312553.XA CN201911312553A CN110987989A CN 110987989 A CN110987989 A CN 110987989A CN 201911312553 A CN201911312553 A CN 201911312553A CN 110987989 A CN110987989 A CN 110987989A
- Authority
- CN
- China
- Prior art keywords
- content
- chloride ions
- sample
- phase
- obtaining
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 title claims abstract description 110
- 239000004568 cement Substances 0.000 title claims abstract description 47
- 238000000034 method Methods 0.000 title claims abstract description 28
- 238000003763 carbonization Methods 0.000 claims abstract description 42
- 239000002002 slurry Substances 0.000 claims abstract description 16
- 238000012360 testing method Methods 0.000 claims description 19
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 12
- 230000008569 process Effects 0.000 claims description 9
- 239000000843 powder Substances 0.000 claims description 6
- 239000011780 sodium chloride Substances 0.000 claims description 6
- 238000005520 cutting process Methods 0.000 claims description 5
- 238000001035 drying Methods 0.000 claims description 4
- 238000012423 maintenance Methods 0.000 claims description 4
- 238000011282 treatment Methods 0.000 claims description 4
- 238000001291 vacuum drying Methods 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 3
- 238000002441 X-ray diffraction Methods 0.000 claims description 3
- 238000005516 engineering process Methods 0.000 claims description 3
- 238000010000 carbonizing Methods 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
- 238000002360 preparation method Methods 0.000 claims description 2
- 238000007789 sealing Methods 0.000 claims description 2
- 230000036571 hydration Effects 0.000 abstract description 19
- 238000006703 hydration reaction Methods 0.000 abstract description 19
- 230000015556 catabolic process Effects 0.000 abstract description 10
- 238000006731 degradation reaction Methods 0.000 abstract description 10
- 230000009471 action Effects 0.000 abstract description 5
- 239000011159 matrix material Substances 0.000 abstract description 4
- 230000007547 defect Effects 0.000 abstract description 3
- 150000003839 salts Chemical class 0.000 description 10
- 239000000499 gel Substances 0.000 description 7
- 239000000243 solution Substances 0.000 description 7
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 5
- 239000000920 calcium hydroxide Substances 0.000 description 5
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 5
- 230000007797 corrosion Effects 0.000 description 5
- 238000005260 corrosion Methods 0.000 description 5
- 229910001653 ettringite Inorganic materials 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 239000011575 calcium Substances 0.000 description 2
- 239000000378 calcium silicate Substances 0.000 description 2
- 229910052918 calcium silicate Inorganic materials 0.000 description 2
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000011440 grout Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000012266 salt solution Substances 0.000 description 2
- -1 C-S-H gels Chemical compound 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 239000011398 Portland cement Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- OSMSIOKMMFKNIL-UHFFFAOYSA-N calcium;silicon Chemical compound [Ca]=[Si] OSMSIOKMMFKNIL-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
- G01N23/20008—Constructional details of analysers, e.g. characterised by X-ray source, detector or optical system; Accessories therefor; Preparing specimens therefor
- G01N23/2005—Preparation of powder samples therefor
Landscapes
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Analysing Materials By The Use Of Radiation (AREA)
- Preparation Of Clay, And Manufacture Of Mixtures Containing Clay Or Cement (AREA)
Abstract
The invention belongs to the technical field of determination of chloride ion content in concrete, and particularly relates to a method for obtaining the content of chloride ions combined with various phases in cement paste. The method is based on the thermodynamic theory, utilizes the difference of degradation rates of different phases in a cement hydration system in a low pH environment, takes carbonization as a means for changing the phase stability in a concrete system, and ensures that the combined chloride ions in the matrix consist of chloride ions combined by a single phase under the action of a carbonized degradation phase, thereby accurately researching the chloride ion combination behavior of the phases, obtaining the content of the combined chloride ions of the different phases in actual cement slurry, and overcoming the defect of researching the content of the combined chloride ions of the cement slurry by researching the synthesized hydration products.
Description
Technical Field
The invention belongs to the technical field of determination of chloride ion content in concrete, and particularly relates to a method for obtaining the content of chloride ions combined with various phases in cement paste.
Background
The information disclosed in this background of the invention is only for enhancement of understanding of the general background of the invention and is not necessarily to be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
It is known that chloride ion corrosion in marine environments is one of the most important causes of the deterioration of concrete structures by causing corrosion of steel reinforcements. When chloride ions invade from the external environment to the interior of the concrete, one part of the chloride ions can be combined with cement hydration products to form combined chloride ions, and the other part of the chloride ions can be dissolved in the pore solution as free chloride ions and can migrate to the deep. Because the free chloride ions in the pore solution induce the corrosion of the steel bars, the formation of the combined chloride ions can relatively reduce the amount of the free chloride ions, thereby playing a role in delaying the corrosion of the steel bars, and therefore, the chloride ion combined content of the cement slurry in the concrete has important influence on the durability of the concrete structure.
The bound chloride ion content of the cement slurry is closely related to its hydration product. Cement hydration products include calcium silicate hydrate (C-S-H gel), monosulfide compounds (AFm), ettringite (Aft), Calcium Hydroxide (CH), and the like. The content of different hydration products is different, and the specific mechanism of the combination of the hydration products and chloride ions is different, so that the combination content of the chloride ions of different phases in the cement paste is difficult to evaluate, the delay effect of the existence of related phases in the concrete on the migration of the chloride ions cannot be clearly clarified, and the accuracy of the prediction of the service life of the concrete structure is greatly limited. Therefore, the research on the chloride ion binding content of different phases in the hardened cement paste under the chloride corrosion condition is very important for the accurate evaluation of the concrete durability and the accurate prediction of the service life of the concrete structure in the ocean engineering.
Currently, obtaining the content of bound chloride ions of different phases is achieved by artificially synthesized hydration products. For example, Hiroshi Hirao et al artificially synthesized calcium silicate hydrate (C-S-H gel), monosulfide (AFm), ettringite (Aft), etc., and then put these synthesized phases into salt solutions of a certain concentration, respectively (note that only one phase is put in one salt solution), and after reaching chloride ion binding equilibrium, the bound chloride ion content of the different phases was tested to reflect the chloride ion binding content of the different phases in the actual cement slurry (see document 1). However, the inventor researches and discovers that: although the chloride ion binding content of a single phase can be obtained more directly by studying the synthesized hydration product, which has the advantages of convenience and intuition, two problems exist. First, the synthetic hydration product is not completely equivalent to the product produced by actual hydration. For example, the calcium-silicon ratio (Ca/Si) of synthesized C-S-H cannot be completely matched with that of hydration, and considering that Ca/Si is an important factor influencing the binding of C-S-H with chloride ions, the synthesized C-S-H cannot truly reflect the chloride ion binding capacity of the C-S-H generated by actual hydration. Second, the synthesized hydration product does not bind chloride ions in the complete phase system, and the interaction between the phases cannot be considered.
Documents of the prior art
Document 1: hiroshi Hirao, Kazuo Yamada, Haruka Takahashi, HassanZibara. chloride Binding of center Estimated by Binding Isthers of hydroxides [ J ]. Journal of Advanced Concrete Technology,2005,1:77-84.
Disclosure of Invention
In order to avoid the defects of an artificial synthesis method and reflect the chloride ion binding capacity of different phases in the actual cement paste, the invention provides a method for obtaining the content of chloride ions bound by multiple phases in the cement paste.
In order to achieve the above purpose, the present invention further finds that: carbonization is a typical factor that leads to changes in the phase stability of concrete systems. Under the action of carbonization, the concrete matrix gradually changes from high alkalinity to neutrality. During this process, the phase will exhibit different degrees of degradation at different rates depending on its thermal stability.
Therefore, if the total bound chloride ions in the matrix can be made up of single phase-bound chloride ions by the action of the carbonized degradation phase, the chloride ion binding behavior of the phase can be more accurately studied.
Therefore, the invention discloses the following technical scheme, and the method for obtaining the content of the chloride ions combined with various phases in the cement paste comprises the following steps:
(1) the neat paste specimens with internal chloride ion binding equilibrium are cut into sheet samples.
(2) One set of the sheet samples was vacuum dried to avoid carbonization, and the other set of the sheet samples was carbonized for different periods of time to obtain samples of different degrees of carbonization including non-carbonized sheet samples.
(3) The samples that reached the carbonization time were vacuum dried and each sample was separately milled into powder samples, wherein each sample yielded a powder sample that was divided into three portions: the first part was used to test pH to characterize the degree of carbonation; a second part for testing the total chloride ion content and the free chloride ion content in the sample to obtain a bound chloride ion content; the third part is used for quantitatively characterizing the content of each phase in the sample.
(4) And (4) determining the total combined chloride ion content and the content of each phase in the samples under different carbonization degrees based on the test result of the step (3), wherein the specific content is as follows:
the content of each phase in the sample is greatly different and the degradation rate is different, and the phase with the smaller content and the higher degradation rate is decomposed along with the increase of the carbonization time, so that the residual content of the combined chloride ions in the sample is composed of the chloride ions combined by the phases which are not decomposed, and therefore, the quantitative relation between the content of the combined chloride ions in the sample and the content of the phase which is not decomposed and is related to the combined chloride ions at different carbonization times can be expressed by the following series of equations. Therefore, by making the bound chloride ion of the sample consist of a single phase bound chloride ion by carbonization, the content of the bound chloride ion per phase can be obtained, and further the content of another bound chloride ion related to the bound chloride ion can be obtained. The series of equations is shown in equations 1-5:
in formulae 1-4, A0、A1、A2、A3、A4、B0、B1、B2、B3、C0、C1、C2、D0、D1、E0The content of the phase related to the combined chloride ions in the unit sample after different carbonization treatments; x, y, z, w and mu are the content of the combined chloride ions in each unit phase; cb0、Cb1、Cb2、Cb3、Cb4The total bound chloride ion content per sample at different carbonization times. It should be noted that the above formula is not exhaustive, and if necessary, more phase-bound chloride ions can be determined by controlling the carbonization degree (time).
Further, the above carbonization degree means: and with the increase of the carbonization time, one less undegraded substance is contained in the sample than the previous sample, and one more undegraded substance is contained in the sample than the next sample, until only one undegraded substance phase is remained in the last group of samples, so that all unknowns are solved according to the condition that the number of unknowns to be solved is equal to the number of equations.
Further, in the step (1), the preparation method of the neat paste test piece comprises the following steps: preparing cement slurry by using cement and sodium chloride solution, and then performing reverse mould forming and maintenance to obtain the cement paste test piece containing saturated chloride ions.
Optionally, the mass concentration of the sodium chloride solution is 3-10%, and the water-cement ratio is 0.3-0.6: 1. the sodium chloride solution is used both to provide chloride ions and as a blending water.
Optionally, the process of the reverse mold forming comprises: and (3) pouring the cement slurry, and then placing the cement slurry in a sealing device with the humidity of 85-95% (preferably 90%) for standing for 20-28 h (preferably 24 h).
Optionally, the curing process is as follows: and (3) maintaining the mixture for not less than 30 days in a sealed box with room temperature and relative humidity of 85-95% to ensure that the chloride ion combination is balanced. And the direct contact between the test piece and water or solution is avoided in the maintenance process, and the loss of chloride ions among the test pieces is prevented.
Further, in the step (1), absolute ethyl alcohol is adopted in the cutting process for cooling treatment, so that the loss of chloride ions in the test piece is avoided.
Further, in the step (1), the thickness of the sheet-shaped sample is 1.0-2.5 mm, preferably 2 mm.
Further, in the step (2), the carbonization process comprises: temperature of 20 + -1 deg.C, humidity of 70 + -2%, and CO2The concentration is 10-100% (preferably 20%), and the carbonization time is 3-56 days.
Further, in the steps (2) and (3), the temperature of the vacuum drying is 40-50 ℃ (preferably 45 ℃), and the drying time is 7-14 d.
Further, in the step (3), the XRD technology is utilized to quantitatively characterize the content of each phase in the sample.
Compared with the prior art, the invention has the following beneficial effects: the method is based on the thermodynamic theory, utilizes the difference of degradation rates of different phases in a cement hydration system in a low pH environment, takes carbonization as a means for changing the phase stability in a concrete system, and ensures that the combined chloride ions in the matrix consist of chloride ions combined by a single phase under the action of a carbonized degradation phase, thereby accurately researching the chloride ion combination behavior of the phases, obtaining the content of the combined chloride ions of the different phases in actual cement slurry, and overcoming the defect of researching the content of the combined chloride ions of the cement slurry by researching the synthesized hydration products.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.
FIG. 1 is a graph of pH values of various sets of samples after different carbonization times in examples of the present invention.
FIG. 2 is a graph showing the chloride ion content of various groups of samples after different carbonization times in the examples of the present invention.
FIG. 3 is a graph showing the content of the main phase in each set of samples after different carbonization times in the examples of the present invention.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
As described in the background, the study of the bound chloride ion content of cement slurry by the synthesized hydration product does not completely equal the product generated by actual hydration, and the synthesized hydration product does not bind chloride ions in the complete phase system, so that the problem of mutual influence between phases cannot be considered. Therefore, the invention provides a method for obtaining the content of multiple phase-bound chloride ions in cement paste; the invention will now be further described with reference to the drawings and detailed description.
Examples
A method for obtaining the content of multiple phase-bound chloride ions in cement paste comprises the following steps:
(1) mixing ordinary portland cement and a 10% sodium chloride solution (simultaneously serving as mixing water) according to a water-cement ratio of 0.4: 1 preparing cement grout containing chloride ions, pouring the grout into a mold, and standing for 24 hours in a sealed mold with the humidity of 90%; and (3) curing for 30 days in a sealed box with the temperature of about 23 ℃ and the relative humidity of 90% after demolding, ensuring that the chloride ion combination reaches balance, and obtaining a neat paste test piece with the balanced internal chloride ion combination.
(2) Five groups of samples are cut out from the net slurry test piece by using a precision cutting machine, each group of samples comprises 4 thin sheet samples with the thickness of about 2.0mm, and the cutting process adopts absolute ethyl alcohol to carry out cooling treatment, so that the loss of chloride ions in the test piece is avoided.
(3) A set of sheet samples was placed in a vacuum oven at 45 ℃ until completely dried (sample 1); the other four groups of sheet samples are respectively put in a carbonization box (the temperature is 20 +/-1 ℃, the humidity is 70 +/-2 percent, and CO is added)2The volume concentration is 20 +/-1 percent), carbonizing for 3 days, 7 days, 14 days and 28 days (samples 2-5), respectively taking out the carbonized samples after reaching the carbonization period, putting the carbonized samples into a vacuum drying oven, and drying the carbonized samples at the temperature of 45 ℃ for 7 days to achieve complete drying.
(5) Respectively preparing five groups of dried sheet samples into powder samples by using a vibration mill, averagely dividing the powder samples obtained by each group of samples into three parts, and measuring the pH values of different samples by using a pH measuring instrument in the first part so as to reflect the carbonization degrees of 5 groups of samples; the second part utilizes the general concrete long-term performance and durability test method standard (GB/T50082-2009) to test the total ion content and the free chloride ion content of the sample, thereby obtaining the combined chloride ion content of the sample; the third part characterizes the content of five major phases, namely CSH gel, Friede's salt, Kuzel's salt, Aft, CH, in a sample using an X-ray diffraction instrument (reference: Chang H. chlorine binding capacity of fluidized by carbon carbide under reactor conditions [ J ]. center & ConcretElectrosites, 2017,84: 1-9).
The phases associated with chloride binding are mainly five types of C-S-H gel, Friede 'S salt, Kuzel' S salt, Aft, CH, so the following equation set can be established:
in the formula, A0、A3、A7、A14、A28The contents of C-S-H gel in the unit sample when carbonized for 0d, 3d, 7d, 14d and 28d are sequentially obtained; b is0、B3、B7、B14The content of Calcium Hydroxide (CH) in a unit sample is sequentially carbonized for 0d, 3d, 7d and 14 d; c0、C3、C7Sequentially obtaining the contents of Friedel's salt in a unit sample at 0d, 3d and 7d of carbonization; d0、D3Sequentially controlling the content of ettringite (Aft) in the unit sample at 0d and 3d of carbonization; e0The content of Kuzel's salt per unit sample at carbonization time 0 d; x, y, z, w and u are the contents of combined chloride ions in the units of C-S-H gel, calcium hydroxide, Friedel 'S salt, ettringite and Kuzel' S salt in the sample in sequence; cb0、Cb3、Cb7、Cb14、Cb28The total combined chloride ion content in the unit sample is 0d, 3d, 7d, 14d and 28d of carbonization in sequence.
The experimental data are brought into an equation set, and the chloride ion binding content of the main related phase in the actual cement paste can be obtained. The pH, bound chloride ion content, and phase content of the resulting five groups of samples are shown in fig. 1, 2, and 3, respectively.
It can be seen from fig. 1 that the pH of the sample gradually decreases with the increase of the carbonization time, because the cement slurry gradually changes from high alkalinity to neutral under the carbonization action.
It can be seen from fig. 2 that the bound chloride ion content is significantly reduced with increasing carbonization time, since carbonization converts part of the bound chloride ions into free chloride ions.
It can be seen from fig. 3 that the content of each phase in the sample is greatly different and the degradation rate is different, and the phases with smaller content and faster degradation rate may be decomposed one by one as the carbonization degree is increased. Wherein substances closely related to the binding of chloride ions, such as C-S-H gels, Friedel 'S salts, Kuzel' S salts, etc., decrease with increasing carbonization time, the residual bound chloride ion content of the sample is constituted by chloride ions bound by the not yet decomposed phase.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (9)
1. The method for obtaining the content of the chloride ions combined with various phases in the cement paste is characterized by comprising the following steps of:
(1) cutting the clean slurry test piece with the internal chloride ion combination balanced into a sheet sample;
(2) vacuum drying one group of sheet samples to avoid carbonization, and carbonizing the other group of sheet samples for different time to obtain samples with different carbonization degrees including non-carbonized sheet samples;
(3) the samples that reached the carbonization time were vacuum dried and each sample was separately milled into powder samples, wherein each sample yielded a powder sample that was divided into three portions: the first part was used to test pH to characterize the degree of carbonation; a second part for testing the total chloride ion content and the free chloride ion content in the sample to obtain a bound chloride ion content; the third part is used for quantitatively characterizing the content of each phase in the sample.
(4) And (4) determining the total combined chloride ion content and the content of each phase in the samples under different carbonization degrees based on the test result of the step (3), wherein the specific content is as follows:
in formulae 1-4, A0、A1、A2、A3、A4、B0、B1、B2、B3、C0、C1、C2、D0、D1、E0The content of the phase related to the combined chloride ions in the unit sample after different carbonization treatments; x, y, z, w and mu are the content of the combined chloride ions in each unit phase; cb0、Cb1、Cb2、Cb3、Cb4The total bound chloride ion content per sample at different carbonization times.
2. The method for obtaining the content of the multiple phase-bonded chloride ions in the cement paste according to claim 1, wherein in the step (1), the preparation method of the neat paste test piece comprises the following steps: preparing cement slurry by using cement and sodium chloride solution, and then performing reverse mould forming and maintenance to obtain the cement paste test piece containing saturated chloride ions.
3. The method for obtaining the content of the multiple phase-bonded chloride ions in the cement paste according to claim 1, wherein the mass concentration of the sodium chloride solution is 3-10%, and the water-cement ratio is 0.3-0.6: 1.
4. the method for obtaining the content of the multiple phase-bonded chloride ions in the cement paste according to claim 2, wherein the reverse-mold forming process comprises the following steps: pouring the cement slurry into a mold, and then placing the mold in a sealing device with the humidity of 85-95% (preferably 90%) for standing for 20-28 h, preferably 24 h;
preferably, the curing process is as follows: maintaining the mixture in a sealed box with room temperature and relative humidity of 85-95% for no less than 30 days; and the direct contact of the test piece with water or solution is avoided in the maintenance process.
5. The method for obtaining the content of the multiple phase-bonded chloride ions in the cement paste according to claim 1, wherein in the step (1), the cutting process is performed with absolute ethyl alcohol for temperature reduction.
6. The method for obtaining the content of multiple phase-bonded chloride ions in the cement paste according to any one of claims 1 to 5, wherein in the step (1), the thickness of the sheet sample is 1.0 to 2.5mm, preferably 2 mm.
7. The method for obtaining the content of the multiple phase-bonded chloride ions in the cement paste according to any one of claims 1 to 5, wherein in the step (2), the carbonization process comprises: temperature of 20 + -1 deg.C, humidity of 70 + -2%, and CO2The concentration is 10-100%, preferably 20%, and the carbonization time is 3-56 days.
8. The method for obtaining the content of multiple phase-bonded chloride ions in the cement paste according to any one of claims 1 to 5, wherein in the steps (2) and (3), the temperature of vacuum drying is 40 to 50 ℃ (preferably 45 ℃) and the drying time is 7 to 14 days, preferably 7 days.
9. The method for obtaining the content of the multiple phase-bound chloride ions in the cement paste according to any one of claims 1 to 5, wherein in the step (3), the content of each phase in the sample is quantitatively characterized by using an XRD (X-ray diffraction) technology.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911312553.XA CN110987989B (en) | 2019-12-18 | 2019-12-18 | Method for obtaining content of multiple phase-bound chloride ions in cement paste |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911312553.XA CN110987989B (en) | 2019-12-18 | 2019-12-18 | Method for obtaining content of multiple phase-bound chloride ions in cement paste |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110987989A true CN110987989A (en) | 2020-04-10 |
| CN110987989B CN110987989B (en) | 2020-11-20 |
Family
ID=70095707
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911312553.XA Expired - Fee Related CN110987989B (en) | 2019-12-18 | 2019-12-18 | Method for obtaining content of multiple phase-bound chloride ions in cement paste |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110987989B (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011158437A (en) * | 2010-02-04 | 2011-08-18 | East Nippon Expressway Co Ltd | Method for quickly measuring chloride ion concentration in hardened concrete |
| CN102680387A (en) * | 2012-04-28 | 2012-09-19 | 中交四航工程研究院有限公司 | Real-time monitoring sensor for durability of concrete structures and fabricating method thereof |
| CN103207221A (en) * | 2013-03-22 | 2013-07-17 | 中交四航工程研究院有限公司 | Sensor for monitoring depth distribution of concentration and pH (potential of hydrogen) values of chloride ions in concrete protective layer and method for manufacturing sensor |
| CN103487570A (en) * | 2013-09-29 | 2014-01-01 | 北京航空航天大学 | Method for testing accelerated life of reinforced concrete in chloride environment |
| CN106802318A (en) * | 2017-01-09 | 2017-06-06 | 北京工业大学 | A kind of assay method of hydrated cement paste chlorion fixed amount |
| WO2018156896A1 (en) * | 2017-02-24 | 2018-08-30 | Worcester Polytechnic Institute | Method for enzymatic repair of cementitious surfaces |
| CN108827989A (en) * | 2018-06-29 | 2018-11-16 | 山东大学 | A kind of method that C-S-H gel adsorption combination chloride ion accounts for total binding chloride ion ratio in measurement cement paste |
| CN110133175A (en) * | 2019-05-07 | 2019-08-16 | 山东大学 | The method of chloride ion content is combined under a kind of accurate Characterization difference carbonizing degree in cement slurry |
-
2019
- 2019-12-18 CN CN201911312553.XA patent/CN110987989B/en not_active Expired - Fee Related
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011158437A (en) * | 2010-02-04 | 2011-08-18 | East Nippon Expressway Co Ltd | Method for quickly measuring chloride ion concentration in hardened concrete |
| CN102680387A (en) * | 2012-04-28 | 2012-09-19 | 中交四航工程研究院有限公司 | Real-time monitoring sensor for durability of concrete structures and fabricating method thereof |
| CN103207221A (en) * | 2013-03-22 | 2013-07-17 | 中交四航工程研究院有限公司 | Sensor for monitoring depth distribution of concentration and pH (potential of hydrogen) values of chloride ions in concrete protective layer and method for manufacturing sensor |
| CN103487570A (en) * | 2013-09-29 | 2014-01-01 | 北京航空航天大学 | Method for testing accelerated life of reinforced concrete in chloride environment |
| CN106802318A (en) * | 2017-01-09 | 2017-06-06 | 北京工业大学 | A kind of assay method of hydrated cement paste chlorion fixed amount |
| WO2018156896A1 (en) * | 2017-02-24 | 2018-08-30 | Worcester Polytechnic Institute | Method for enzymatic repair of cementitious surfaces |
| CN108827989A (en) * | 2018-06-29 | 2018-11-16 | 山东大学 | A kind of method that C-S-H gel adsorption combination chloride ion accounts for total binding chloride ion ratio in measurement cement paste |
| CN110133175A (en) * | 2019-05-07 | 2019-08-16 | 山东大学 | The method of chloride ion content is combined under a kind of accurate Characterization difference carbonizing degree in cement slurry |
Non-Patent Citations (3)
| Title |
|---|
| HONGLEI CHANG ET AL: ""A novel method for assessing C-S一H chloride adsorption in cement pastes"", 《CONSTRUCTION AND BUILDING MATERIALS》 * |
| HONGLEI CHANG ET AL: ""Influence of Pore Structure on Chloride Penetration in Cement Pastes Subject to Wetting-Drying Cycles"", 《ADVANCES IN MATERIALS SCIENCE AND ENGINEERING》 * |
| ZHIQIANG YANG ET AL: ""Improving the chloride binding capacity of cement paste by addingnano-A1203"", 《CONSTRUCTION AND BUILDING MATERIALS》 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110987989B (en) | 2020-11-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Bentz et al. | Relating compressive strength to heat release in mortars | |
| Dhir et al. | Evaluation of Portland limestone cements for use in concrete construction | |
| Grilo et al. | New natural hydraulic lime mortars–physical and microstructural properties in different curing conditions | |
| Ye et al. | Influence of limestone powder used as filler in SCC on hydration and microstructure of cement pastes | |
| Wang et al. | Drying shrinkage of alkali-activated fly ash/slag blended system | |
| Shi et al. | Effects of chloride ion binding on microstructure of cement pastes | |
| Zhou et al. | Strength deterioration of concrete in sulfate environment: an experimental study and theoretical modeling | |
| Liu et al. | Long-term performance of blended cement paste containing fly ash against sodium sulfate attack | |
| Chen et al. | Microstructural development of hydrating portland cement paste at early ages investigated with non-destructive methods and numerical simulation | |
| Champenois et al. | Beneficial use of a cell coupling rheometry, conductimetry, and calorimetry to investigate the early age hydration of calcium sulfoaluminate cement | |
| Du et al. | Effect of different humidity-controlling modes on microstructure and compressive behavior of ordinary concrete | |
| Li et al. | Sulfate resistance and hydration products of steam cured steel slag blended cement mortar under dry–wet cycle | |
| Chang et al. | Chloride binding behavior of calcium silicate hydrates and Friedel's salt of pastes | |
| Chen et al. | Study on the metakaolin-based geopolymer pervious concrete (MKGPC) and its removal capability of heavy metal ions | |
| Hanumananaik et al. | Shrinkage in low-calcium fly ash geopolymers for precast applications: Reaction product content and pore structure under drying conditions | |
| CN110987989B (en) | Method for obtaining content of multiple phase-bound chloride ions in cement paste | |
| Rabehi et al. | Durability and thermal stability of ultra high-performance fibre-reinforced concrete (UHPFRC) incorporating calcined clay | |
| Matsushita et al. | Effect of curing temperature and water to cement ratio on hydration of cement compounds | |
| CN108827989B (en) | Method for determining proportion of C-S-H gel adsorption-bound chloride ions in total bound chloride ions in cement paste | |
| Yu et al. | Ionic diffusion across an interface between chloride-free and chloride-containing cementitious materials | |
| Persson | Consequence of cement constituents, mix composition and curing conditions for self-desiccation in concrete | |
| Yu et al. | Chloride penetration and microstructure development of fly ash concrete | |
| Hanumananaik et al. | Influence of Process Variables on Shrinkage in Low-Calcium Fly-Ash Geopolymers | |
| Liu et al. | Study on the durability of concrete with mineral admixtures to sulfate attack by wet-dry cycle method | |
| Shi et al. | Effects of temperature and humidity on properties of ethylene/vinyl acetate‐modified ternary complex mortar |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20200907 Address after: 250000 No. 27 South Grand Road, Shandong, Ji'nan Applicant after: SHANDONG University Applicant after: Shandong high speed Group Co.,Ltd. Address before: 250100, No. 27, Da Nan Road, Licheng District, Shandong, Ji'nan Applicant before: SHANDONG University Applicant before: QILU TRANSPORTATION DEVELOPMENT GROUP Co.,Ltd. |
|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20201120 |