Method for detecting residual equivalent weight of flocculating agent in washed fine aggregate

Abstract

The invention relates to the field of test and detection of building materials, in particular to a method for detecting the residual equivalent weight of a flocculating agent in washed fine aggregate, which comprises the following steps: preparing standard samples containing flocculating agents with different concentrations, detecting to obtain a first standard fluidity and drawing a standard curve; a clear soaking solution obtained by fully soaking the washed fine aggregate replaces a flocculant solution to prepare a detection sample, first detection fluidity is obtained through detection, and the residual equivalent of the flocculant in the washed fine aggregate is obtained by combining the standard curve. According to the method, the influence of the difference of the sand on the fluidity is eliminated, the accurate residual equivalent of the flocculating agent is obtained, and the method has high universality.

Description

Technical Field

[0001] The invention relates to the field of building material testing and detection, and in particular to a method for detecting the residual equivalent of a flocculant in water-washed fine aggregate. Background Art

[0002] Fine aggregate is one of the important raw materials for preparing concrete and mortar, and the wastewater from washing fine aggregate is prone to environmental pollution. Therefore, the wastewater after washing fine aggregate is usually recycled and reused. In the process of sewage recycling and recycling, flocculants are usually added to the sewage to achieve rapid sedimentation of silt in the sewage, and then separated, so that the circulating water is clear and meets the standards for recycling. However, the amount of flocculant added to sewage of different concentrations is different, which leads to the fact that the recycled washed fine aggregate is usually mixed with an uncertain amount of flocculant. Since flocculants will affect the quality of concrete, the recovered fine aggregates need to be tested for the residual equivalent of flocculants before use.

[0003] At present, the field generally adopts indoor mixing of small samples with the same concrete ratio, and observes the first working performance and time loss of the mixture to judge the residual condition of the flocculant. This method is time-consuming, requires a lot of time for verification, and requires the cooperation of multiple people, which is less practical. Summary of the invention

[0004] The object of the present invention is to provide a convenient and quick method for detecting the residual equivalent of flocculant in water-washed fine aggregate.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for detecting the residual equivalent of flocculant in water-washed fine aggregates, comprising:

[0007] A plurality of standard samples are formed by mixing flocculants of different concentrations with a preset formula, and the concentration of the flocculant in each standard sample is recorded as a standard concentration, wherein the flocculant is a type used in the production process of washed fine aggregate;

[0008] After each standard sample is prepared, a sample is taken immediately to perform a fluidity test and record the fluidity as the first standard fluidity;

[0009] A standard curve is fitted according to the first standard fluidity and the standard concentration, and the determination coefficient R of the standard curve is 2 Greater than 0.9;

[0010] Taking a first mass of the washed fine aggregate and adding it to a second mass of water for soaking and sedimentation, taking the supernatant as the soaking liquid, and using the soaking liquid to replace at least part of the water in the preset formula to prepare the test sample;

[0011] After the test sample is prepared, a sample is taken immediately to perform a fluidity test and record the fluidity as the first test;

[0012] The residual equivalent of the flocculant in the water-washed fine aggregate is determined in combination with the first detection fluidity, the standard curve, the component distribution ratio of the standard sample, the first mass, and the second mass.

[0013] Optionally, the detection method further comprises:

[0014] At the first moment after each standard sample is prepared, a sample is taken to perform fluidity detection and the fluidity is recorded as the second standard fluidity;

[0015] At the first time after the test sample is prepared, a sample is taken to perform a fluidity test and the fluidity is recorded as a second test fluidity.

[0016] Optionally, the first moment is any value between 0.8h and 1.2h.

[0017] Optionally, the value of the second standard fluidity detected when the standard concentration of the standard sample is 0 is taken as an initial value. When the value of the second standard fluidity detected by the standard sample is less than or equal to 95% of the initial value, the standard sample is used for fitting the standard curve.

[0018] Optionally, the step of blending flocculants of different concentrations with a preset formula to form a plurality of standard samples comprises:

[0019] Dissolving the flocculants of different concentrations in water at a first temperature to form standard solutions of different concentrations;

[0020] Using a plurality of the standard solutions of different concentrations to prepare a plurality of the standard samples according to the preset formula;

[0021] The standard sample is cement paste, and in the step of taking a first mass of the washed fine aggregate and adding it to a second mass of water for immersion and sedimentation, the temperature of the water is the first temperature.

[0022] Optionally, when the flocculant is an anionic polyacrylamide flocculant and the molecular weight of the flocculant is any value between 10 million and 30 million, the first temperature is any value between 40° C. and 55° C.

[0023] Optionally, when the flocculant is an anionic polyacrylamide flocculant and the molecular weight of the flocculant is any value between 10 million and 30 million, the standard curve is y=Ax 2 -B x+C, where y is the standard concentration, x is the first standard fluidity, and A, B and C are the parameters to be fitted.

[0024] Optionally, the water-to-binder ratio in the preset formula is any value between 0.25 and 0.45.

[0025] Optionally, the relative humidity of the environment during the fluidity test is greater than 50%.

[0026] Optionally, the fluidity test includes testing using a cement mortar fluidity tester and a truncated cone circular mold, and the time from sampling the standard sample or the test sample to the end of the test is less than 1.5 minutes.

[0027] The beneficial effects of the present invention are as follows: the flocculant in the washed fine aggregate is dissolved by soaking, and the test sample is configured with the obtained soaking liquid instead of directly configuring the test sample with the washed fine aggregate, so that the influence of the changes in the fineness modulus, mud content, artificial sand mother rock and other characteristics of the sand material on the fluidity of the mortar can be eliminated, thereby excluding the influence of other factors on the fluidity as much as possible, forming the influence relationship of a single variable, obtaining a standard curve indicating the correlation between the flocculant concentration and the fluidity of the mortar, and obtaining a more accurate flocculant content, and the same standard curve can be used to detect washed fine aggregates of different specifications with the same type of flocculant, and different types of flocculants can also be detected by drawing standard curves respectively, and it has high universality.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flow chart of a method for detecting the residual equivalent of flocculant in washed fine aggregates shown in Example 1 of the present invention;

[0030] Figure 2 A graph showing the standard concentration, the first standard fluidity and the second standard fluidity corresponding to a plurality of standard samples in the first embodiment of the present invention;

[0031] Figure 3 for Figure 2 Two standard curves were drawn after discarding some samples;

[0032] Figure 4 for Figure 3 The standard curve corresponding to the first standard fluidity is obtained by swapping the horizontal and vertical coordinates of the standard curve;

[0033] Figure 5 for Figure 3 The standard curve obtained by swapping the horizontal and vertical coordinates of the standard curve corresponding to the second standard fluidity. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0035] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] See also Figure 1 The method for detecting the residual equivalent of flocculant in the washed fine aggregate to be protected by the present invention comprises:

[0039] S1. A plurality of standard samples are formed by mixing flocculants of different concentrations with a preset formula, and the concentration of the flocculant in each standard sample is recorded as the standard concentration, wherein the flocculant is a type used in the production process of washed fine aggregate;

[0040] S2. After each standard sample is prepared, take a sample immediately, perform fluidity test and record them as the first standard fluidity;

[0041] S3, fitting the standard curve according to the first standard fluidity and standard concentration, the determination coefficient R of the standard curve 2 Greater than 0.9;

[0042] S4, taking a first mass of washed fine aggregate and adding it to a second mass of water for immersion and sedimentation, taking the supernatant as the immersion liquid, and using the immersion liquid to replace at least part of the water in the preset formula to prepare the test sample;

[0043] S5. After the test sample is prepared, take a sample immediately, perform a fluidity test and record it as the first test fluidity;

[0044] S6. Determine the residual equivalent of the flocculant in the washed fine aggregate by combining the first detection fluidity, the standard curve, the component distribution ratio of the standard sample, the first mass and the second mass.

[0045] By soaking the flocculant in the washed fine aggregate to dissolve it, and using the obtained soaking liquid to prepare the test sample instead of directly using the washed fine aggregate to prepare the test sample, the influence of changes in the fineness modulus, mud content, artificial sand mother rock and other properties of the sand on the fluidity of the mortar can be eliminated, thereby eliminating the influence of other factors on the fluidity as much as possible, forming a single variable influence relationship, and obtaining a standard curve indicating the correlation between the flocculant concentration and the fluidity of the mortar, and obtaining a more accurate flocculant content. The same standard curve can be used to detect washed fine aggregates of different specifications with the same type of flocculant, and different types of flocculants can also be detected by drawing standard curves separately, which has high universality.

[0046] In some embodiments, the detection method further comprises:

[0047] Take a sample at the first moment after each standard sample is prepared, perform fluidity test and record them as the second standard fluidity respectively;

[0048] At the first moment after the test sample is prepared, a sample is taken to perform a fluidity test and the fluidity is recorded as the second test fluidity.

[0049] When mixing concrete, admixtures are usually added. During the mixing process of concrete, admixtures improve the charge distribution on the surface of cement particles, reduce the mutual attraction between particles, and thus release the ability of free water wrapped between particles. This ability enables concrete to achieve higher fluidity at the same water-cement ratio. Flocculants usually have positive or negative charges and long molecular chains. They usually form larger flocs from suspended matter and colloidal particles in water through bridging, netting, and electrical neutralization to achieve sewage purification. When flocculants are evenly mixed with cement, cement particles will agglomerate, and as the dosage of flocculants increases, the degree of aggregation between particles will intensify, resulting in more free water wrapped by agglomerated cement particles, which will lead to a decrease in the fluidity of the slurry. Flocculants and admixtures have similar and opposite mechanisms of action. Before the concentration of flocculants reaches a critical value, the effect on fluidity is small. After the concentration exceeds the critical value, the effect on fluidity is significant. At the same time, due to the slow-release effect of the admixture, when the concentration of the flocculant is less than the critical value, its effect on the initial water reduction rate of the admixture is more obvious, and the initial slump of the concrete will be significantly reduced, while the effect on the performance of the concrete mixture will be relatively small. By letting the slurry stand for a period of time and testing the fluidity over time, the critical point where the fluidity over time changes from almost no change to significant change can be found, which helps to assist in the standard curve value selection and obtain a more reliable standard curve. In addition, through multiple sets of standard reference values, multiple test results can be obtained, which helps to improve the accuracy of judgment.

[0050] In some embodiments, the value of the second standard fluidity detected when the standard concentration of the standard sample is 0 is taken as the initial value. When the value of the second standard fluidity detected by the standard sample is less than or equal to 95% of the initial value, the standard sample is used for fitting the standard curve, so as to eliminate the influence of the initial water reduction rate on the fluidity as much as possible through the selection of standard samples, thereby improving the credibility of the standard curve and the accuracy of the detection.

[0051] In some embodiments, the first time is any value between 0.8h and 1.2h, for example, any value between 0.8h, 0.9h, 1.0h, 1.1h and 1.2h. It is helpful to maintain the effect of the initial water reduction rate of the admixture.

[0052] In some embodiments, the step of blending a predetermined formula with different concentrations of flocculants to form a plurality of standard samples comprises:

[0053] Dissolving flocculants of different concentrations in water at a first temperature to form standard solutions of different concentrations;

[0054] Using multiple standard solutions of different concentrations to prepare multiple standard samples according to a preset formula;

[0055] The standard sample is cement paste. A first mass of washed fine aggregate is added to a second mass of water for immersion and sedimentation. The temperature of the water is a first temperature.

[0056] By forming standard solutions and soaking solutions with water at an appropriate temperature, it helps to quickly and fully dissolve the flocculant and helps to control variables.

[0057] In some embodiments, when the flocculant is an anionic polyacrylamide flocculant and the molecular weight of the flocculant is any value between 10 million and 30 million, the first temperature is any value between 40°C and 55°C, for example, it can be any value between 40°C, 45°C, 50°C and 55°C, which helps the flocculant to fully dissolve.

[0058] In some embodiments, when the flocculant is an anionic polyacrylamide flocculant and the molecular weight of the flocculant is any value between 10 million and 30 million, the standard curve is y=Ax 2 -B x+C, where y is the standard concentration, x is the first standard fluidity, and A, B and C are the parameters to be fitted.

[0059] In some embodiments, the water-to-binder ratio in the preset formula is any value between 0.25 and 0.45, for example, it can be any value between 0.25, 0.3, 0.35, 0.4 and 0.45.

[0060] In some embodiments, the first relative humidity is greater than 50%, for example, it may be any value among 50%, 60%, 70%, 80%, 90% and 98%.

[0061] In some embodiments, the fluidity test includes testing using a cement mortar fluidity meter and a truncated cone mold, and the time from sampling the standard sample or the test sample to the end of the test is less than 1.5 minutes, which helps to improve the accuracy of the fluidity test.

[0062] Please refer to the following examples for details.

[0063] Embodiment 1:

[0064] The method for detecting the residual equivalent of flocculant in washed fine aggregate shown in a preferred embodiment of the present application comprises:

[0065] S1. A plurality of standard samples are formed by mixing flocculants of different concentrations with a preset formula, and the concentration of the flocculant in each standard sample is recorded as the standard concentration, wherein the flocculant is a type used in the production process of washed fine aggregate;

[0066] S2. After each standard sample is prepared, take a sample immediately, perform fluidity test and record them as the first standard fluidity;

[0067] S3, fitting the standard curve according to the first standard fluidity and standard concentration, the determination coefficient R of the standard curve 2 Greater than 0.9;

[0068] S4, taking a first mass of washed fine aggregate and adding it to a second mass of water for immersion and sedimentation, taking the supernatant as the immersion liquid, and using the immersion liquid to replace at least part of the water in the preset formula to prepare the test sample;

[0069] S5. After the test sample is prepared, take a sample immediately, perform a fluidity test and record it as the first test fluidity;

[0070] S6. Determine the residual equivalent of the flocculant in the washed fine aggregate by combining the first detection fluidity, the standard curve, the component distribution ratio of the standard sample, the first mass and the second mass.

[0071] In this embodiment, the washed fine aggregate is subsequently used to prepare C40 concrete. The formula of this concrete is: P·O42.5 cement: F class II fly ash: sand: crushed stone: water: admixture = 340: 85: 765: 1057: 157: 5.525 (kg / m 3 ), in order to detect whether the flocculant residue in the washed fine aggregate in this embodiment will affect the quality of concrete, an equivalent residue test is performed, and the flocculant used when recycling the washed fine aggregate is an anionic polyacrylamide flocculant with a molecular weight of 20 million.

[0072] Wherein, step S1 comprises:

[0073] S101. Prepare a flocculant solution with a concentration of 0.05% in water at a temperature of 45°C. The flocculant is the same as the flocculant mixed in the washed fine aggregate.

[0074] S102. Dilute the flocculant solution into standard solutions of different concentrations, and mix the standard solutions with water at a temperature of 45°C to prepare standard samples. The standard sample is a cement paste without sand, and the mixing is carried out in the mixing pot of the cement paste mixer. The mixing operation steps follow the provisions of GB / T 1346-2011. The water-binder ratio of C40 concrete is 0.32. Considering the water absorption of coarse and fine aggregates, the water-binder ratio of the preset formula in this implementation is reduced by 0.02, and P·O42.5 cement and Class F II fly ash are also used. The components of each standard sample are shown in Table 1 below.

[0075] Table 1:

[0076]

[0077] In step S2, in order to expand the gradient of the expansion of the net slurry, the truncated cone test mold specified in "GB / T 2419-2005 Cement Mortar Fluidity Determination Method" is used to conduct a net slurry fluidity test, and the first value and the second value are recorded. To ensure the accuracy of the admixture weighing, the admixture is diluted before use. All raw materials are placed in a constant temperature environment of 20℃±2℃ in advance. The ambient temperature during the test is controlled at 20℃±2℃, and the relative humidity is greater than or equal to 50%, and the time from sampling to the end of the test is controlled within 1.5min.

[0078] Step S2 includes:

[0079] S201. After the preparation of each standard sample is completed, sampling is immediately performed, and the detection and recording of the first standard fluidity are completed quickly.

[0080] S202. After the preparation of each standard sample, let it stand for 1 hour. After stirring at high speed for 30 seconds in the mixing pot of the wetted cement slurry mixer, immediately take a sample to test its fluidity and record it as the second standard fluidity.

[0081] The test results are shown in Table 2 below.

[0082] Table 2:

[0083]

[0084] Draw a curve graph based on the data in the standard, that is, Figure 2 The initial fluidity in the figure is the first standard fluidity of the standard sample, and the fluidity after 1 hour is the second standard fluidity of the standard sample. Analysis shows that when the flocculant concentration in the standard solution is less than or equal to 1.0×10 -2 ‰, although the first standard fluidity of each standard sample showed a downward trend as a whole, the second standard fluidity changed little, indicating that the flocculant at this concentration only affected the initial water reduction rate of the admixture, and had little effect on the later state maintenance, that is, the effect on the state maintenance of the concrete was small, which can be explained that at this concentration equivalent, the impact on the concrete was within the actual acceptable range on site. However, when the flocculant concentration in the standard solution was 1.0×10 -2 ‰ to 2.0×10 -2 ‰, with the increase of flocculant concentration in the standard solution, the first standard fluidity and the second standard fluidity of each standard sample have a significant downward trend. In other words, when the concentration of flocculant begins to have a greater impact on the fluidity of the test sample, the concentration of flocculant is 2.000×10 -2 ‰. In this embodiment, the second standard fluidity value corresponding to the standard sample with a standard concentration of 0 is 225mm, that is, the initial value is 225mm. Combining the above principles and values, it can be judged that when the flocculant concentration equivalent of the detected sample is greater than 2.000×10 -2‰, or the value of the second fluidity test is less than 200mm, that is, when the fluidity loss rate of cement slurry after 1 hour is greater than 10% compared with the initial value, it can be judged that the flocculant residue of this batch of washed fine aggregate is unqualified and is prohibited from entering or leaving the factory.

[0085] See also Figure 3 In step S3, the concentration of flocculant in the standard solution is 1.0×10 -2 ‰ to 10.0×10 -2 The standard curve is fitted with the standard samples between ‰. The initial fluidity in the figure is the first standard fluidity of the standard sample. The polynomial (initial fluidity) is the first standard curve fitted according to the first standard fluidity. Its function equation is y=0.5964x 2 -14.433x+262.36, where y is the first standard fluidity, x is the flocculant concentration in the standard solution, and the determination coefficient R 2 The value is 0.9912, indicating that the correlation between the two is very good. The credible range of this standard curve is the fluidity range above 175 mm. The fluidity after 1 hour in the figure is the second standard fluidity of the standard sample, and the polynomial (fluidity after 1 hour) is the second standard curve fitted according to the second standard fluidity, and its function equation is y=0.3249x 2 -10.656x+224.94, where y is the second standard fluidity, x is the flocculant concentration in the standard solution, and the determination coefficient R 2 The confidence range of this standard curve is the range where the second test fluidity is above 150 mm.

[0086] See also Figure 4 In order to facilitate the calculation of flocculant concentration, in this embodiment Figure 3 The first standard fluidity is used as the horizontal coordinate, the standard concentration is used as the vertical coordinate, and the third standard curve is refitted. The standard curve is y = 0.1043x 2 -56.415x+7691.8, where x is the first standard fluidity, y is the flocculant concentration in the standard solution, and R 2 It is 0.9858, indicating that the two are well correlated.

[0087] See also Figure 5 In order to verify the rigor of the calculation results of the third standard curve, in this embodiment Figure 3 The second standard fluidity is used as the horizontal coordinate and the standard concentration is used as the vertical coordinate. The fourth standard curve is refitted. The standard curve is y = 0.0954x 2 -48.635x+6158.8, where x is the second standard fluidity, y is the flocculant concentration in the standard solution, and R 2It is 0.9932, indicating that the two are well correlated.

[0088] Step S4 includes:

[0089] S401. Weigh 3 kg of wet-process sand for engineering. In this embodiment, the fineness modulus of the machine-made sand is 2.5, and the stone powder content is 5.5%. Measure the moisture content of the machine-made sand according to the specification requirements, and add 45°C water in proportion. The water-sand ratio in the C40 formula is 20.5%. To ensure that the flocculant is fully dissolved, the water-sand ratio after water replenishment is twice the water-sand ratio in C40, that is, 41.0%. Stir slowly in the mixing pot of the mortar mixer for 10 minutes to accelerate the dissolution of the residual flocculant in the machine-made sand.

[0090] S402. After stirring, remove the stirring pot and let it stand for 1 minute. Transfer the upper turbid liquid into a 1000mL measuring cylinder and let it stand in an environment of 20℃±2℃ until the supernatant becomes clear. Take the supernatant as the soaking liquid.

[0091] Step S5 includes:

[0092] S501, using immersion liquid to replace the water in step S2 to mix the test sample, and using the same method as step S201 to detect the first test fluidity of the instant sample, and the first test fluidity in this embodiment is 230mm.

[0093] S502. Using the same method as step S501, the second detection fluidity of the sample taken after 1 hour is detected. The second detection fluidity in this embodiment is 197 mm.

[0094] Step S6 includes:

[0095] The concentration of the flocculant in the soaking solution is calculated according to the third standard curve, and the flocculant concentration equivalent is calculated.

[0096] Since the water-to-sand ratio of the soaking liquid in this embodiment is twice that of the original formula, the flocculant concentration equivalent in this embodiment is twice the concentration of the flocculant in the soaking liquid obtained by the test. Substituting the first test fluidity into the third standard curve, the concentration of the flocculant in the soaking liquid is calculated to be 2.3382×10 -2 ‰, the flocculant concentration equivalent is about 4.676×10 -2 ‰.

[0097] In other embodiments, when the concentration of the soaking solution is too high and the test sample is difficult to be applied to the first standard curve, the test may be performed after dilution.

[0098] In this embodiment, step S6 also includes calculating the concentration of the flocculant in the soaking liquid by using the fourth standard curve, and comparing and verifying the value calculated by the third standard curve. Combining the fourth standard curve equation and the second detection fluidity value of 197 mm, the concentration of the flocculant in the soaking liquid is calculated to be 2.8008×10 -2 ‰, by comparison, it can be seen that the difference between the two calculation results is small, so the test results have high reliability.

[0099] This embodiment also includes step S7: combining the inference in step S202, verifying through multiple collapse experiments, and determining the critical condition for the unqualified test sample. In this step, multiple verifications are required, and some verification examples can be found in the following verification and embodiments 2 and 3.

[0100] According to the data obtained in this example, the flocculant concentration equivalent is about 4.676×10 -2 ‰, the second test fluidity is 197mm, combined with the inference in step S202, it can be judged that the washed fine aggregate in this embodiment is unqualified. The collapsed test was carried out on the washed fine aggregate in this embodiment, and the test contents and results include:

[0101] S701. At the designed admixture dosage of C40 formula, i.e. 1.2%, the initial state of the concrete mixture is not open.

[0102] S702. Increase the admixture dosage to 1.8%. The initial slump of the concrete mixture is 220mm. At this time, the concrete has poor stickiness and is sticky. After 5 minutes, the concrete oozes out and breaks off the bottom.

[0103] S703. When the admixture dosage is increased to 1.6%, the water consumption is increased by 10kg to 12kg, that is, the water-cement ratio is increased by 0.02 to 0.03. At this time, the initial slump of the concrete mixture meets the requirement of 215mm, the viscosity of the concrete decreases, the stickiness improves, and there is slight seepage, the slurry does not wrap the stone, and the workability deteriorates when discharging the material on site.

[0104] It can be seen from this that the water-washed fine aggregate in this embodiment cannot meet the actual use requirements and the admixture components need to be fine-tuned.

[0105] Embodiment 2:

[0106] The difference between this embodiment and the first embodiment is that the water-washed fine aggregate in this embodiment is water-washed sand with a fineness modulus of 2.7 and a mud content of 1.5%. The first test fluidity is 243 mm, the second test fluidity is 205 mm, and the calculated flocculant concentration equivalent is about 2.835×10 -2 ‰, does not meet the material entry and exit standards.

[0107] The experimental contents and results in step S5 include:

[0108] S701. At the designed dosage of C40 formula, i.e. 1.2%, the slump of the concrete mixture is 190mm, and the slump after 1h is 150mm.

[0109] S702. Increase the admixture dosage to 1.4%. The initial slump of the concrete mixture is 210mm. The concrete is sticky and poor in consistency. It is difficult to discharge the concrete from the mixing plant. After 1 hour, the slump is 175mm.

[0110] S703. Increase the admixture dosage to 1.3%, increase the water consumption by 3kg to 5kg, that is, increase the water-cement ratio by 0.01. At this time, the initial slump of the concrete mixture meets the requirement of 215mm, the viscosity of the concrete decreases, and the stickiness is moderate.

[0111] It can be seen from this that the water-washed fine aggregate in this embodiment cannot meet the actual use requirements and the admixture components need to be fine-tuned.

[0112] Embodiment three:

[0113] The only difference between this embodiment and the first embodiment is that the water-washed fine aggregate in this embodiment is wet-process machine-made sand with a fineness modulus of 2.6 and a mud content of 4.2%. The first test fluidity is 257 mm, the second test fluidity is 225 mm, and the calculated flocculant concentration equivalent is about 1.641×10 -2 ‰, in line with the material entry and exit standards.

[0114] The experimental contents and results in step S5 include:

[0115] S701. At the designed dosage of C40 formula, i.e. 1.2%, the slump of the concrete mixture is 205mm, and the slump after 1h is 195mm.

[0116] S702. Increase the admixture dosage to 1.25%, the initial slump of the concrete mixture is 215mm, the concrete is in good condition, and the slump after 1 hour is 205mm.

[0117] It can be seen from this that the water-washed fine aggregate in this embodiment can meet actual usage requirements.

[0118] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0119] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for detecting the residual equivalent of flocculant in washed fine aggregate, characterized in that: include: A plurality of standard samples are formed by mixing flocculants of different concentrations with a preset formula, and the concentration of the flocculant in each standard sample is recorded as a standard concentration, wherein the flocculant is a type used in the production process of washed fine aggregate; After each standard sample is prepared, a sample is taken immediately to perform a fluidity test and record the fluidity as the first standard fluidity; A standard curve is fitted according to the first standard fluidity and the standard concentration, and the determination coefficient R of the standard curve is 2 Greater than 0.9; Taking a first mass of the washed fine aggregate and adding it to a second mass of water for soaking and sedimentation, taking the supernatant as the soaking liquid, and using the soaking liquid to replace at least part of the water in the preset formula to prepare the test sample; After the test sample is prepared, a sample is taken immediately to perform a fluidity test and record the fluidity as the first test; The residual equivalent of the flocculant in the water-washed fine aggregate is determined in combination with the first detection fluidity, the standard curve, the component distribution ratio of the standard sample, the first mass, and the second mass.

2. The detection method according to claim 1, characterized in that Also includes: At the first moment after each standard sample is prepared, a sample is taken to perform fluidity detection and the fluidity is recorded as the second standard fluidity; At the first time after the test sample is prepared, a sample is taken to perform a fluidity test and the fluidity is recorded as a second test fluidity.

3. The detection method according to claim 2, characterized in that The first time is any value between 0.8h and 1.2h.

4. The detection method according to claim 2, characterized in that Taking the value of the second standard fluidity detected when the standard concentration of the standard sample is 0 as an initial value, when the value of the second standard fluidity detected by the standard sample is less than or equal to 95% of the initial value, the standard sample is used for fitting the standard curve.

5. The detection method according to any one of claims 1 to 4, characterized in that: The step of blending a preset formula with flocculants of different concentrations to form a plurality of standard samples comprises: Dissolving the flocculants of different concentrations in water at a first temperature to form standard solutions of different concentrations; Using a plurality of the standard solutions of different concentrations to prepare a plurality of the standard samples according to the preset formula; The standard sample is cement paste, and in the step of taking a first mass of the washed fine aggregate and adding it to a second mass of water for immersion and sedimentation, the temperature of the water is the first temperature.

6. The detection method according to claim 5, characterized in that When the flocculant is an anionic polyacrylamide flocculant and the molecular weight of the flocculant is any value between 10 million and 30 million, the first temperature is any value between 40° C. and 55° C.

7. The detection method according to any one of claims 1 to 4, characterized in that: When the flocculant is an anionic polyacrylamide flocculant and the molecular weight of the flocculant is any value between 10 million and 30 million, the standard curve is y=Ax 2 -B x+C, where y is the standard concentration, x is the first standard fluidity, and A, B and C are the parameters to be fitted.

8. The detection method according to claim 1, characterized in that The water-to-binder ratio in the preset formula is any value between 0.25 and 0.

45.

9. The detection method according to claim 1, characterized in that: The relative humidity of the environment during the fluidity test is greater than 50%.

10. The detection method according to claim 1, characterized in that: The fluidity test includes testing through a cement mortar fluidity tester and a truncated cone circular mold, and the time from sampling the standard sample or the test sample to the end of the test is less than 1.5 minutes.

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