Method for detecting mixing amount of steel slag in steel slag improved soil

Abstract

The invention discloses a steel slag mixing amount detection method for steel slag improved soil, and belongs to the technical field of highway construction. The method comprises the following steps: taking a steel slag sample and a high-liquid-limit soil sample, and preparing steel slag high-liquid-limit improved soil with different mixing amounts; deionized water and an acid solution leaching agent are adopted to soak the steel slag high-liquid-limit improved soil to obtain multiple soak solutions A; testing the conductivity of the soaking solution A, and drawing a steel slag doping amount-conductivity relation standard curve; sampling the steel slag improved soil roadbed, and soaking the steel slag improved soil roadbed with deionized water and an acid solution leaching agent respectively to obtain a plurality of soak solutions B; and testing the conductivity of the soak solution B, and reading the corresponding steel slag doping amount on the steel slag doping amount-conductivity relation standard curve according to the conductivity test result of the soak solution B and the PH value of the soak solution B. The method has the beneficial effects that the problem of steel slag mixing amount construction quality detection is solved, and obstacles are cleared away for promoting application of the steel slag in the improved high liquid limit soil engineering.

Description

Technical Field

[0001] The invention belongs to the technical field of highway construction, and in particular relates to a method for detecting the amount of steel slag added to steel slag-improved soil. Background Art

[0002] In highway engineering, soil with a liquid limit of more than 50% is called high liquid limit soil. High liquid limit soil is a kind of unsuitable soil for direct embankment filling. Generally, it can only be used for highway roadbed filling after being improved. The conventional methods are: chemical improvement method with lime, cement and other substances; physical improvement method with crushed stone, gravel and other substances.

[0003] Using steel slag to improve high liquid limit soil is a relatively new improvement method. The particle size distribution range of steel slag is 0.001-20mm; the particle density generally exceeds 3.1-3.7g / cm 3 (The density of soil particles is generally 2.6g / cm 3 The main cation in the particles is Ca 2+ , Fe 2+ Mg 2+ , Mn 2+ 、Zn 2+ , Cu 2+ Cr 2+ Therefore, the principle of steel slag improving high liquid limit soil is: the continuous precipitation of high-valent cations in the particles and the low-valent Na + Ion exchange reduces the liquid limit of high liquid limit soil; large-particle steel slag is added to the soil to improve the soil gradation and increase the soil strength. Therefore, steel slag improves high liquid limit soil with both chemical and physical improvement effects. Experiments and practice have shown that the high liquid limit soil improved by 10% to 15% steel slag by mass has a good effect, significantly reducing the liquid limit of high liquid limit soil and improving the strength of improved soil, which has significant engineering promotion and application value.

[0004] In engineering, testing whether the dosage of improved materials meets the design requirements is an important measure to ensure the quality of the project. For chemically improved soil, the highway field generally determines whether the improved materials meet the design requirements by testing the effective calcium and magnesium content in the improved soil. The method is "T0809-2009 Cement or lime dosage determination method in cement or lime stabilized materials" of the "Testing Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (JTG 3441-2024). The principle is to test the Ca content in the leachate of the on-site improved soil mixture. 2+ Mg 2+ ion content, so as to judge whether the lime cement content in the improved soil meets the design requirements.

[0005] As there is no professional method for testing the amount of steel slag added to improve high liquid limit soil, the project also uses the method of measuring effective calcium and magnesium content to test the amount of steel slag in an analogy with lime cement, but the result is not accurate. The reason is that steel slag is industrial solid waste, which is not intentionally produced, so its composition is unstable, so the Ca in its leachate is not stable. 2+ Mg 2+ The ion content is unstable, so the method of using lime and cement to improve soil to test the effective calcium and magnesium content to detect the dosage of the improver is not suitable for steel slag solid waste to improve soil.

[0006] Therefore, it is necessary to provide a method specifically for detecting the amount of steel slag modified with high liquid limit soil to solve the above problems. Summary of the invention

[0007] The object of the present invention is to provide a method for detecting the amount of steel slag in steel slag-improved soil, which uses a method mainly based on testing the conductivity of the steel slag-improved soil leachate and auxiliary method based on testing the density of the steel slag-improved soil to determine the amount of steel slag in the improved soil, thereby solving at least one technical problem involved in the background technology.

[0008] In order to solve the above-mentioned technical problems, the present invention is achieved as follows:

[0009] The present invention provides a method for detecting the amount of steel slag modified soil steel slag, comprising the following steps:

[0010] Step S1, taking steel slag samples and high liquid limit soil samples, and preparing 6 steel slag high liquid limit improved soils with different dosages of 0, designed dosage, and designed dosage ±2-6%;

[0011] Step S2, using deionized water with a pH value of 7.0 and an acid solution with a pH value of 3.2 as leaching agents to soak different amounts of steel slag high liquid limit improved soil, respectively, to obtain multiple soaking solutions A;

[0012] Step S3, using a conductivity tester to test the conductivity of the immersion solution A, and drawing standard curves of the relationship between slag dosage and conductivity corresponding to pH values ​​of 7.0 and 3.2 respectively according to the test results;

[0013] Step S4, sampling the slag-improved soil roadbed, and soaking it with deionized water with a pH value of 7.0 and an acid solution with a pH value of 3.2, respectively, to obtain a plurality of soaking solutions B;

[0014] Step S5, using a conductivity tester to test the conductivity of the soaking liquid B, and reading the corresponding slag dosage on the standard curve of the slag dosage-conductivity relationship corresponding to the corresponding pH value according to the conductivity test result of the soaking liquid B and the pH value of the soaking liquid B.

[0015] Optionally, the acidic solution leaching agent is prepared by using deionized water and hydrochloric acid.

[0016] Optionally, in step S2, the soaking time is 4 hours.

[0017] Optionally, after step S5, step S6 is further included, in which the construction quality is quickly judged by using the read slag content, which specifically includes:

[0018] If the difference between the two slag content values ​​read out according to the standard curve of slag content-conductivity relationship corresponding to pH value 7.0 and the standard curve of slag content-conductivity relationship corresponding to pH value 3.2 is less than 2%, the average value of the two slag content values ​​read out is taken as the test result; if the difference between the two slag content values ​​read out is greater than 2%, there is a problem in the construction, and it is necessary to find out the problem before determining the test result.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The steel slag dosage is determined by using the conductivity test results. The test method takes into account the unstable characteristics of solid waste components and directly applies the principle of high liquid limit improved soil, which solves the problem of steel slag dosage construction quality inspection and clears the obstacles for promoting the application of steel slag in improving high liquid limit soil projects.

[0021] (2) The use of conductivity test results to determine the amount of steel slag added is in line with the improvement principle of steel slag improved soil, that is, the higher the content of high-valent cations in the improved soil, the better the improvement effect, and the improvement effect can be reflected by conductivity;

[0022] (3) According to the cation leaching characteristics of steel slag, two pH values ​​are used to prepare the immersion solution, and two test results are used for verification, which can avoid the problem of the test being deceived by fraud;

[0023] (4) By soaking the steel slag-improved soil with two leaching agents with large pH values, two conductivity test results with large differences can be obtained. If the two results obtained by sampling are close, it means that this is not the result of steel slag soaking, but may be the result of adding other electrolytes, thereby discovering the problem of falsification by the construction workers. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0025] Figure 1 The standard curve diagram of the relationship between steel slag dosage and electrical conductivity provided by the present invention. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The embodiment of the present invention provides a method for detecting the amount of steel slag modified soil steel slag, comprising the following steps:

[0028] Step S1, taking steel slag samples and high liquid limit soil samples, and preparing 6 steel slag high liquid limit improved soils with different dosages of 0, designed dosage, and designed dosage ±2-6%;

[0029] Step S2, using deionized water with a pH value of 7.0 and an acid solution with a pH value of 3.2 as leaching agents to soak different amounts of steel slag high liquid limit improved soil, respectively, to obtain multiple soaking solutions A;

[0030] Step S3, using a conductivity tester to test the conductivity of the immersion solution A, and drawing standard curves of the relationship between slag dosage and conductivity corresponding to pH values ​​of 7.0 and 3.2 respectively according to the test results;

[0031] Step S4, sampling the slag-improved soil roadbed, and soaking it with deionized water with a pH value of 7.0 and an acid solution with a pH value of 3.2, respectively, to obtain a plurality of soaking solutions B;

[0032] Step S5, using a conductivity tester to test the conductivity of the soaking liquid B, and reading the corresponding slag dosage on the standard curve of the slag dosage-conductivity relationship corresponding to the corresponding pH value according to the conductivity test result of the soaking liquid B and the pH value of the soaking liquid B.

[0033] The acid solution leaching agent is prepared from deionized water and hydrochloric acid, and the immersion time is 4 hours.

[0034] After step S5, step S6 is also included, in which the construction quality is quickly judged by using the read slag content, which specifically includes:

[0035] If the difference between the two slag content values ​​read out according to the standard curve of slag content-conductivity relationship corresponding to pH value 7.0 and the standard curve of slag content-conductivity relationship corresponding to pH value 3.2 is less than 2%, the average value of the two slag content values ​​read out is taken as the test result; if the difference between the two slag content values ​​read out is greater than 2%, there is a problem in the construction, and it is necessary to find out the problem before determining the test result.

[0036] It should be further explained that for steel slag of the same particle size, the smaller the pH value of the leaching agent, the greater the mass concentration of the leached heavy metal ions. Therefore, by using two leaching agents with large pH values ​​to soak the steel slag-improved soil, two conductivity test results with large differences can be obtained (see Figure 1 If the two sampling results are close or the difference between them is greater than the difference between the two curves with the same dosage on the standard curve, it means that the conductivity obtained is not only the result of slag immersion, but may be the result of adding other electrolytes, or the quality of the improved high liquid limit soil has changed, so it is found that the test results cannot reflect the actual construction situation.

[0037] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0038] In addition, it should be noted that the scope of the methods and systems in the embodiments of the present invention is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved. For example, the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.

[0039] The embodiments of the present invention are described above, but the present invention is not limited to the above-mentioned specific implementation modes. The above-mentioned specific implementation modes are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A method for detecting the amount of steel slag modified soil steel slag, characterized in that: The steps include: Step S1, taking steel slag samples and high liquid limit soil samples, and preparing 6 steel slag high liquid limit improved soils with different dosages of 0, designed dosage, and designed dosage ±2-6%; Step S2, using deionized water with a pH value of 7.0 and an acid solution with a pH value of 3.2 as leaching agents to soak different amounts of steel slag high liquid limit improved soil, respectively, to obtain multiple soaking solutions A; Step S3, using a conductivity tester to test the conductivity of the immersion solution A, and drawing standard curves of the relationship between slag dosage and conductivity corresponding to pH values ​​of 7.0 and 3.2 respectively according to the test results; Step S4, sampling the slag-improved soil roadbed, and soaking it with deionized water with a pH value of 7.0 and an acid solution with a pH value of 3.2, respectively, to obtain a plurality of soaking solutions B; Step S5, using a conductivity tester to test the conductivity of the soaking liquid B, and reading the corresponding slag dosage on the standard curve of the slag dosage-conductivity relationship corresponding to the corresponding pH value according to the conductivity test result of the soaking liquid B and the pH value of the soaking liquid B.

2. The method for detecting the amount of steel slag modified soil according to claim 1, characterized in that: The acid solution leaching agent is prepared from deionized water and hydrochloric acid.

3. The method for detecting the amount of steel slag modified soil according to claim 1, characterized in that: In step S2, the soaking time is 4 hours.

4. The method for detecting the amount of steel slag modified soil according to claim 1, characterized in that: After step S5, step S6 is also included, in which the construction quality is quickly judged by using the read slag content, which specifically includes: If the difference between the two slag content values ​​read out according to the standard curve of slag content-conductivity relationship corresponding to pH value 7.0 and the standard curve of slag content-conductivity relationship corresponding to pH value 3.2 is less than 2%, the average value of the two slag content values ​​read out is taken as the test result; if the difference between the two slag content values ​​read out is greater than 2%, there is a problem in the construction, and it is necessary to find out the problem before determining the test result.

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