Rapid evaluation method for volume density of light plastering gypsum

Abstract

The invention relates to the field of material testing, in particular to a rapid evaluation method for the volume density of light plastering gypsum. According to the method, the time-consuming bottleneck of traditional testing is broken through by constructing the quantitative relation model of the wet density and the dry density. The method comprises the following core steps: (1) determining the hydration water consumption of a gypsum system: determining the water consumption (b%) required by complete hydration of gypsum through an actual measurement method or a theoretical calculation method; (2) obtaining real-time parameters: measuring the standard consistency water addition amount (w%) and the wet density (rho wet) of the freshly mixed slurry; and (3) quickly calculating the dry density: calculating the volume density (dry volume weight) through an exclusive formula based on the hydration water amount, the water adding amount and the wet density. According to the method, the volume density can be calculated based on the instant measurable parameters (such as the wet density and the water adding amount), instant evaluation of the volume density in the production process can be achieved so as to facilitate timely regulation and control, the defects that a traditional testing method is long in period and poor in timeliness are overcome, and the method is high in accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of material testing, in particular to a rapid evaluation method for the bulk density of light plastering gypsum. BACKGROUND

[0002] Light plastering gypsum is a kind of gypsum mortar used for indoor wall and ceiling base plastering and leveling, which is made of gypsum (hemihydrate gypsum (CaSO4·0.5H2O), type II anhydrite (AII-CaSO4) alone or mixture of both) as the main cementitious material, mixed with light aggregates such as expanded perlite, vitrified microbeads and additives. As a widely used building material, the high-quality production of light plastering gypsum is of great significance.

[0003] At present, most of the products on the market are light plastering gypsums with hemihydrate gypsum as the main cementitious material, i.e. LA type in GB / T 28627-2023.

[0004] In the production process of light plastering gypsum, bulk density is a key performance indicator, which directly affects the quality and use effect of the product. The national standard requires that the bulk density of light plastering gypsum should be ≤1000kg / m 3 . However, the traditional bulk density test method (such as standard GB / T 28627-2023) requires curing the product for 7 days, then drying to constant weight, finally weighing and testing and calculating, which takes at least more than one week. This test method has the following problems: (1) long cycle: curing and drying takes more than 1 week, which seriously lags behind the production rhythm; (2) poor timeliness: the bulk density data cannot be obtained in time after the product is prepared, which makes it difficult to optimize the production process in time according to the test results, and it is difficult to realize effective production control, which reduces the production efficiency; (3) complicated process: multiple weighing and long time constant temperature control, high labor and equipment cost. Therefore, there is an urgent need for a method to quickly evaluate the bulk density of light plastering gypsum. SUMMARY

[0005] Therefore, the present application provides a rapid evaluation method for the bulk density of light plastering gypsum, which can test the bulk density in time and realize real-time monitoring and regulation of quality indicators in the production process, overcoming the defects of long cycle and poor timeliness of traditional test methods. The present application provides a rapid evaluation method for the bulk density of light plastering gypsum, comprising the following steps:

[0006] S1, obtaining the hydration water consumption ratio of gypsum powder in the light plastering gypsum formula:

[0007] The method for obtaining is selected from any one of the following (1) to (2):

[0008] (1) test method:

[0009] Take a certain amount of gypsum powder sample and measure its mass a; mix the gypsum powder sample with water, cure it, and then dry it to constant weight, and record the mass a′ at this time; calculate the water consumption ratio b% of gypsum powder hydration using the following formula (Ⅰ-1);

[0010] b%=(a′-a) / a×100% formula (I-1);

[0011] The gypsum powder sample has the same composition as the gypsum powder in the lightweight plaster formula;

[0012] (2) Calculation method:

[0013] Assuming the lightweight plaster formula contains n types of plaster powder, record the dosage C of each type of plaster powder in the lightweight plaster formula. i Determine the adsorbed water content ω in each type of gypsum powder. ai Type III anhydrous gypsum content ω Ai and hemihydrate gypsum content ω aHHi The percentage of water consumed in gypsum powder hydration, b%, is calculated using the following formula (Ⅰ-2);

[0014]

[0015] In (1) to (2) above, the percentage of water consumed in the hydration of gypsum powder is b%, which is the percentage of the mass of water consumed in the complete hydration of gypsum powder in the lightweight plaster formula relative to the mass of gypsum powder.

[0016] S2. Determine the standard consistency water addition amount and test the wet density of the mixed slurry:

[0017] (S2a): Determine the standard consistency of the lightweight plaster of water addition w%.

[0018] (S2b): Test the wet density of the mixed slurry:

[0019] Weigh out lightweight plaster and measure its mass as m2; calculate the required mixing water volume m3 = m2 × w%, and weigh out the corresponding mass of mixing water;

[0020] The weighed lightweight plaster was mixed with mixing water to obtain a slurry; the wet density ρ of the slurry was tested. 湿 The unit is kg / m³ 3 ;

[0021] S3. Calculate the bulk density:

[0022] Calculate the bulk density using any of the following methods (1) to (2):

[0023] Method (1):

[0024] The method (1) comprises the following steps:

[0025] (1.1) calculating the evaporated water amount W2:

[0026] Let the percentage content of the gypsum powder in the light-weight plastering gypsum formula be C%;

[0027] The evaporated water amount W2 is calculated by the following formula (I-3X):

[0028] W2= p 湿 / (1+w%)×w%- p 湿 / (1+w%)×C%×b% formula (I-3X);

[0029] (1.2) calculating the bulk density p:

[0030] The bulk density p is calculated by the following formula (I-3Y):

[0031] p= p 湿 -W2 formula (I-3Y);

[0032] Method (2):

[0033] The bulk density p is calculated by the following formula (I-3):

[0034] p= p 湿 / (1+w%)×(1+C%×b%) formula (I-3).

[0035] Preferably, in step S1, the mass ratio of the gypsum powder sample to water is 1:(0.5-1.0).

[0036] Preferably, in step S1, the temperature condition of the curing is (20±5)℃.

[0037] Preferably, in step S1, the curing time is 1-3h.

[0038] Preferably, in step S1, the drying temperature is 40-60℃.

[0039] Preferably, in step S2, the wet density is measured by a density measuring tool.

[0040] Preferably, the content of the gypsum powder in the light-weight plastering gypsum is ≥30%.

[0041] Preferably, in method (1) in step S1, the method of weighing the gypsum powder sample comprises:

[0042] If there is only one kind of gypsum powder in the light-weight plastering gypsum formula, only the one kind of gypsum powder is weighed as the gypsum powder sample;

[0043] If the gypsum powder in the light plastering gypsum formula contains multiple kinds, the multiple kinds of gypsum powder are weighed and mixed according to the proportion between the multiple kinds of gypsum powder in the light plastering gypsum formula to obtain the gypsum powder sample.

[0044] Preferably, the method (1) in step S1 is further selected from the following methods:

[0045] Suppose that the light plastering gypsum formula contains n kinds of gypsum powder, and the content of each kind of gypsum powder in the light plastering gypsum formula is C i The n kinds of gypsum powder are weighed and tested for quality a i respectively; each kind of gypsum powder is mixed with water, cured, and then dried to constant weight, and the quality a i ' at this time is recorded respectively; the hydration water consumption proportion b i % of each kind of gypsum powder is calculated by the following formula (I-1X)' and then the hydration water consumption proportion b

[0046] b i % of the n kinds of gypsum powder is calculated by the following formula (I-1Y)': i i i ×100% formula (I-1X)';

[0047]

[0048] wherein,

[0049] n≥1;

[0050] C i represents the content of the i-th kind of gypsum powder in the light plastering gypsum formula, i=1~n.

[0051] Preferably, the light plastering gypsum is LA type light plastering gypsum.

[0052] The application provides a rapid evaluation method for the volume density of light plastering gypsum, which breaks through the time-consuming bottleneck of traditional testing by constructing a quantitative relationship model of wet density and dry density. The core steps include: (1) determining the water consumption of gypsum hydration: determining the water consumption (b%) required for complete hydration of gypsum by actual measurement or theoretical calculation; (2) obtaining instant parameters: determining the standard consistency water addition (w%) and the wet density (ρ 湿 ​​); (3) quickly calculate the dry density: based on the hydration water amount, water addition amount and wet density, the volume density (dry bulk density) is calculated through the exclusive formula. The above method can calculate the volume density based on the instant measurable parameters (wet density, water addition amount, etc.), so that the instant evaluation of the volume density in the production process can be realized, so as to timely regulate and overcome the defects of long period and poor timeliness of the traditional test method, and the test result of the method is close to the measured value, and the error is less than 3%, thereby ensuring high accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0054] Figure 1 The linear relationship diagram between the test result and the measured value in the embodiment 3 of the present application. DETAILED DESCRIPTION

[0055] Unless otherwise defined, 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. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application.

[0056] In this document, the technical features described in an open way include both the closed technical solution consisting of the listed features and the open technical solution containing the listed features.

[0057] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0058] In this document, when referring to ranges of values, the ranges are to be read as being inclusive of the minimum and maximum values in the range, unless otherwise indicated. Further, when a range is provided, it is intended to encompass every value within the range, including the minimum value and the maximum value, as well as any whole integer within the range. Also, when describing features or characteristics, multiple ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood as encompassing any and all sub-ranges subsumed therein.

[0059] In this document, when referring to ranges of values, the ranges are to be read as being inclusive of the minimum and maximum values in the range, unless otherwise indicated. Further, when a range is provided, it is intended to encompass every value within the range, including the minimum value and the maximum value, as well as any whole integer within the range. Also, when describing features or characteristics, multiple ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood as encompassing any and all sub-ranges subsumed therein.

[0060] The application provides a method for rapidly evaluating the volume density of light plastering gypsum, comprising the following steps:

[0061] S1, obtaining the hydration water consumption proportion of gypsum powder in a light plastering gypsum formula:

[0062] The method for obtaining is selected from any one of the following (1) to (2):

[0063] (1) test method:

[0064] A certain amount of gypsum powder sample is taken, and the mass a thereof is measured; the gypsum powder sample is mixed with water, cured, and then dried to constant weight, and the mass a' thereof at this time is recorded; the hydration water consumption proportion b% of the gypsum powder is calculated through the following formula (I-1):

[0065] b% = (a' - a) / a x 100% formula (I-1);

[0066] The composition of the gypsum powder sample is the same as that of the gypsum powder in the light plastering gypsum formula;

[0067] (2) calculation method:

[0068] It is assumed that the light plastering gypsum formula contains n kinds of gypsum powder, and the mixing amount C of each kind of gypsum powder in the light plastering gypsum formula is recorded i , the attached water content ω ai , the content of type III anhydrous gypsum ω Ai and the content of hemihydrate gypsum ω aHHi of each kind of gypsum powder are determined; the hydration water consumption proportion b% of the gypsum powder is calculated through the following formula (I-2):

[0069]

[0070] In the above (1) to (2), the hydration water consumption proportion b% of the gypsum powder is the percentage of the mass of water consumed by the complete hydration of the gypsum powder in the light plastering gypsum formula to the mass of the gypsum powder;

[0071] S2, determining the standard consistency water consumption and testing the wet density of the mixed slurry:

[0072] (S2a): determining the standard consistency water consumption w% of the light plastering gypsum;

[0073] (S2b): testing the wet density of the mixed slurry:

[0074] The light plastering gypsum is weighed, and the mass thereof is measured as m2; the required mixed water amount m3 = m2 x w% is calculated, and the mixed water with the corresponding mass is weighed;

[0075] The weighed lightweight plaster was mixed with mixing water to obtain a slurry; the wet density ρ of the slurry was tested. 湿 The unit is kg / m³ 3 ;

[0076] S3. Calculate the bulk density:

[0077] Calculate the bulk density using any of the following methods (1) to (2):

[0078] Method (1):

[0079] The method (1) includes the following steps:

[0080] (1.1) Calculate the amount of water evaporated:

[0081] The percentage content of gypsum powder in the aforementioned lightweight plaster formula is denoted as C%.

[0082] The evaporation rate W2 is calculated using the following formula (Ⅰ-3X):

[0083] W2=ρ 湿 / (1+w%)×w%-ρ 湿 / (1+w%)×C%×b% formula (Ⅰ-3X);

[0084] (1.2) Calculate the bulk density:

[0085] The bulk density ρ is calculated using the following formula (Ⅰ-3Y):

[0086] ρ=ρ 湿 - W2 formula (Ⅰ-3Y);

[0087] Method (2):

[0088] The bulk density ρ is calculated using the following formula (Ⅰ-3):

[0089] ρ=ρ 湿 / (1+w%)×(1+C%×b%)Formula (Ⅰ-3).

[0090] Regarding step S1 :

[0091] S1. Obtain the proportion of water consumed by gypsum powder hydration in the lightweight plaster formulation. The present invention can obtain the proportion of water consumed by gypsum powder hydration in the lightweight plaster formulation to be tested through two methods, namely experimental testing method (1) and theoretical calculation method (2).

[0092] Regarding the testing method (1):

[0093] The method is to take the building gypsum powder for production formula, test the mass increment of the gypsum powder after hydration and drying, that is, the water consumption of the gypsum powder, and then calculate the water consumption of the gypsum powder according to the mass of the gypsum powder sample.

[0094] In the application, the process of the test method is as follows: a certain amount of gypsum powder sample is taken, and the mass a is measured; the gypsum powder sample is mixed with water, cured, and then dried to constant weight, and the mass a' at this time is recorded; the water consumption of the gypsum powder is calculated according to the following formula (I-1): b = (a' - a) / a x 100%.

[0095] In the application, the gypsum powder sample should be representative, and the composition of the gypsum powder in the light plastering gypsum formula should be the same, so as to accurately reflect the characteristics of the gypsum system in the light plastering gypsum formula to be tested. There are two cases: ① if there is only one kind of gypsum powder in the light plastering gypsum formula to be tested, only this kind of gypsum powder is taken as the gypsum powder sample; ② if there are multiple kinds of gypsum powder in the light plastering gypsum formula to be tested, the multiple kinds of gypsum powder are taken and matched according to the proportion of the multiple kinds of gypsum powder in the light plastering gypsum formula to be tested, so as to ensure that the composition of the gypsum powder sample is the same as that of the gypsum powder in the light plastering gypsum formula to be tested.

[0096] In the application, when the gypsum powder sample is mixed with water, the amount of water has no special limitation, and a relative excess amount can make the gypsum powder completely hydrated; but if the amount of water is too high, the subsequent drying intensity will increase, preferably, the mass ratio of the gypsum powder sample to water is 1: (0.5-1.0), specifically, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.0. During the mixing process, the water and the gypsum powder should be fully mixed to ensure the completeness of the hydration reaction.

[0097] In the application, after mixing, curing is performed. The temperature condition of the curing is preferably (20±5) ℃, specifically 15 ℃, 16 ℃, 17 ℃, 18 ℃, 19 ℃, 20 ℃, 21 ℃, 22 ℃, 23 ℃, 24 ℃, 25 ℃. The curing time is preferably 1-3 h, specifically 1 h, 2 h, 3 h, more preferably 2 h. Under this condition, the hemihydrate gypsum can be fully hydrated, laying a foundation for subsequent oven drying to constant weight.

[0098] In the application, after the above curing, drying to constant weight is performed. The drying temperature is preferably 40-60 ℃, specifically 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, more preferably 50 ℃. The drying is usually completed within 24 h.

[0099] In the present application, the target amount b% refers to the percentage of the mass of water consumed in the complete hydration of the gypsum powder to the mass of the gypsum powder, specifically, the percentage of the mass of water consumed in the complete hydration of the gypsum powder sample to the mass of the gypsum powder sample, since the composition of the gypsum powder sample is the same as that of the gypsum powder in the light-weight plaster gypsum formula to be tested, thus, it represents the percentage of the mass of water consumed in the hydration of the gypsum powder in the light-weight plaster gypsum formula to be tested to the mass of the gypsum powder in the light-weight plaster gypsum formula to be tested.

[0100] In the present application, based on the above concept and principle, the percentage b% of water consumption in gypsum powder hydration can also be obtained by the following second method: assuming that the light-weight plaster gypsum formula contains n kinds of gypsum powder (n≥1), and the mixing amount of each kind of gypsum powder in the light-weight plaster gypsum formula is C i , respectively, the n kinds of gypsum powder are weighed and tested for their mass a i (i=1~n); each kind of gypsum powder is mixed with water and cured, and then dried to constant weight, and the mass a i '(i=1~n) at this time is recorded; the percentage b i % of water consumption in the hydration of each kind of gypsum powder is calculated by the following formula (I-1X)' and then the percentage b% of water consumption in the hydration of the n kinds of gypsum powder (i.e. the total gypsum powder) is calculated by the following formula (I-1Y)':

[0101] b i %=(a i '-a i ) / a i ×100% formula (I-1X)';

[0102]

[0103] The above second method is equivalent to separately adding water to each of the n kinds of gypsum powder for mixing and curing, calculating the percentage of water consumption in the hydration of each kind of gypsum powder, and then summing up the percentage of water consumption in the hydration of each kind of gypsum powder in the light-weight plaster gypsum formula to be tested to obtain the total percentage of water consumption in the hydration of the n kinds of gypsum powder. Compared with the first method, the second method requires separately weighing each kind of gypsum powder and separately adding water to each kind of gypsum powder for mixing, curing and calculation, which is more complex in operation, therefore, the first method is preferred. However, it should be noted that the inventive concept and principle of the second method are essentially the same as those of the first method, and therefore, it also belongs to the protection scope of the present application.

[0104] Regarding the calculation method (2):

[0105] This method is to test the phase composition of the building gypsum powder for production, and to calculate the theoretical value of water consumption in hydration by strictly calculating the phase composition, assuming that all anhydrous phases and hemihydrate phases generate dihydrate gypsum.

[0106] The process of the above calculation method is as follows: assuming that the lightweight plaster gypsum formula contains n kinds of gypsum powder, recording the mixing amount C of each kind of gypsum powder in the lightweight plaster gypsum formula i , determining the attached water content ω ai , the content of type III anhydrous gypsum ω Ai and the content of hemihydrate gypsum ω aHHi of each kind of gypsum powder; the hydration water consumption proportion b% of the gypsum powder is calculated by the following formula (I-2);

[0107]

[0108] In the above formula (I-2):

[0109] n≥1. For example, if n gypsum powders from different manufacturers are used in the lightweight plaster gypsum formula to be tested, it means that there are n kinds of gypsum powders.

[0110] C i represents the mixing amount (mass percentage) of the i-th gypsum powder in the lightweight plaster gypsum formula, i=1~n. The mixing amount of each kind of gypsum powder in the lightweight plaster gypsum formula to be tested can be obtained according to the formula of the lightweight plaster gypsum to be tested.

[0111] represents the total mixing amount of the n kinds of gypsum powders in the lightweight plaster gypsum formula.

[0112] The attached water content ω ai , the content of type III anhydrous gypsum ω Ai and the content of hemihydrate gypsum ω aHHi of each kind of gypsum powder can be obtained by testing according to GB / T 36141 “Analysis method of phase composition of building gypsum”.

[0113] The above formula (I-2) is derived based on the stoichiometric relationship of the hydration reaction of the phase composition of gypsum, and is suitable for the industrial production scene when the phase composition of the raw material is stable or the phase composition of each batch of raw material is tested.

[0114] Regarding step S2 :

[0115] S2, determining the standard consistency water content and testing the wet density of the mixed slurry. It includes steps (S2a)-(S2b), which are as follows:

[0116] Regarding step (S2a): determining the standard consistency water content w% of the lightweight plaster gypsum.

[0117] The standard consistency water content w% refers to the percentage of the mass of water required to achieve the standard consistency of lightweight plaster to the mass of the plaster. This invention does not impose any special restrictions on the test method for the standard consistency water content w%, which can be determined according to relevant standards or known testing methods. For example, see section 7.4.1 of GB / T 28627-2023 "Plaster Plaster".

[0118] Regarding step (S2b): Test the wet density of the mixed slurry.

[0119] In this invention, the process of testing the wet density of the mixed slurry is as follows:

[0120] First, weigh a certain amount of lightweight plaster and measure its mass as m2. Based on the standard consistency water addition (w%) from the previous step, calculate the required mixing water volume for the weighed lightweight plaster, m3 = m2 × w%. Then, weigh the corresponding mass of mixing water according to the calculated required mixing water volume (m3). Next, mix the weighed lightweight plaster with the mixing water to form a homogeneous slurry. Finally, test the wet density ρ of the slurry. 湿 The unit is kg / m 3 Among them, the wet density ρ of the tested slurry was... 湿 It can be tested directly using density measuring tools (such as a densitometer).

[0121] Regarding step S3 :

[0122] S3. Calculate the bulk density.

[0123] In this invention, the bulk density can be calculated in two ways, as shown in (1) to (2) below.

[0124] Regarding method (1):

[0125] In this invention, the method (1) includes the following steps: (1.1) calculating the amount of water evaporated; (1.2) calculating the bulk density.

[0126] Regarding (1.1) the calculation of evaporation water:

[0127] In this invention, the percentage content of gypsum powder in the lightweight plaster formula is denoted as C%; then the evaporation water volume W2 is calculated using the following formula (Ⅰ-3X):

[0128] W2=ρ 湿 / (1+w%)×w%-ρ 湿 / (1+w%)×C%×b% formula (Ⅰ-3X);

[0129] It can be seen that, among them, the proportion of water consumed in gypsum powder hydration is b%, the water added to the standard consistency of lightweight talcum gypsum is w%, and the wet density is ρ. 湿In the pre-step, the percentage content C% of gypsum powder in the light plaster gypsum formula (i.e. the percentage of the mass of gypsum powder in the light plaster gypsum formula in the total mass of the light plaster gypsum) has been obtained, and the evaporation water amount W2 can be calculated by the above formula (I-3).

[0130] wherein,

[0131] ρ 湿 / (1+w%) represents the mass of light plaster gypsum dry powder in unit volume of mixed wet slurry, multiplied by w% to obtain the mass of water in unit volume of mixed wet slurry, and then subtracted by the mass of water required for hydration of the gypsum system in unit volume of mixed slurry (i.e. 湿 / (1+w%) x C% x b%), that is, the evaporation water amount, that is, the mass of water in unit volume of mixed slurry that will evaporate.

[0132] The above formula (I-3X) is as follows after operation:

[0133] W2=ρ 湿 / (1+w%) x w% - ρ 湿 / (1+w%) x C% x b%

[0134] =ρ 湿 / (1+w%) x (w% - C% x b%).

[0135] That is, formula (I-3X) can also be written as: W2=ρ 湿 / (1+w%) x (w% - C% x b%). Wherein, w% - C% x b% represents the mass ratio of water in unit mass of light plaster gypsum that exceeds the water required for hydration of the gypsum system.

[0136] Regarding (1.2) calculation of bulk density (dry bulk density):

[0137] In the present application, the bulk density ρ is calculated by the following formula (I-3Y):

[0138] ρ=ρ 湿 -W2 formula (I-3Y).

[0139] wherein,

[0140] ρ 湿 represents the total mass of unit volume of mixed slurry, minus the mass of water evaporated in unit volume of slurry W2, that is, the mass of unit volume of slurry after drying, that is, the bulk density (dry bulk density), and the unit is kg / m 3 .

[0141] The above formula (I-3Y) is as follows after operation:

[0142] ρ=ρ 湿 / (1+w%) - W2

[0143] = p 湿 / (1+w%) - [p 湿 / (1+w%) x w% - p 湿 / (1+w%) x C% x b%]

[0144] = p 湿 / (1+w%) x (1+C% x b%).

[0145] Therefore, formula (I-3Y) can also be written as: p = p 湿 / (1+w%) x (1+C% x b%), i.e. formula (I-3). As can be seen from the above operation, it is not necessary to separately calculate the evaporation water amount W2, but according to the hydration water consumption proportion b% of the gypsum powder, the standard consistency water amount w%, the wet density p 湿 and the gypsum powder content C% in the light plastering gypsum formula to be tested, the bulk density p can be directly calculated by formula (I-3). This is the above-mentioned mode (2). In order to optimize the calculation process and improve the efficiency, mode (2) is preferably adopted.

[0146] In the present application, in the above steps S1-S3, the unit of a certain parameter can have multiple choices (for example, the mass unit can be g, kg, etc. conventional mass unit), and the units of the same type of parameters are unified (for example, for mass parameters, in step S1, if the unit of a is selected as g, the unit of a' must also be g) to ensure the feasibility and consistency of all formula calculations.

[0147] The rapid evaluation method of the present application is not particularly limited to the gypsum content in the light plastering gypsum, and the light plastering gypsum with a gypsum content of ≥30% is preferred. In the present application, the evaluation method is mainly aimed at light plastering gypsum with hemihydrate gypsum as the main gel material (i.e. LA type light plastering gypsum), and its principle can be extended to light plastering gypsum with type II anhydrite as the main gel material (i.e. LB type light plastering gypsum) or light plastering gypsum with a mixture of hemihydrate gypsum and type II anhydrite as the main gel material (i.e. LC type light plastering gypsum). The method of the present application can be applied to light plastering gypsum containing multiple different building gypsums.

[0148] The key technical points of the inventive concept are as follows:

[0149] Under the condition of new mixing state of light plastering gypsum, there is excess water in the system, and only the water that does not participate in hydration needs to be removed, and then the bulk density of the hardened body can be calculated. The inventive concept is developed around solving the time-consuming problem of testing the bulk density of light plastering gypsum, and the key technical point lies in establishing a rapid calculation relationship between the wet density and the dry density through specific steps. Specifically as follows:

[0150] (1) Hydration water amount quantification technology: Through experimental measurement or phase composition calculation, the amount of water required for gypsum hydration is accurately obtained, and the quantitative relationship between hydration reaction and water consumption is established, providing a benchmark parameter for dry density calculation;

[0151] (2) Instant parameter coupling method: The standard water addition amount is combined with the wet density of freshly mixed slurry to establish a direct correlation between production process parameters and physical performance indicators, so that the test data can reflect the slurry state in real time;

[0152] (3) Evaporation water deduction model: Based on the principle of mass conservation, the hydration combined water and free evaporation water are separated through a special formula, breaking through the limitations of traditional methods relying on long-term curing, and realizing the rapid derivation of dry density.

[0153] Compared with the prior art, the present application has the following beneficial effects:

[0154] (1) Efficiency is significantly improved: The 7-day curing and long-time drying process is abandoned, and the volume density calculation can be completed within a few hours by testing the wet density, water addition amount and other parameters in real time, saving several days of time compared with the traditional method;

[0155] (2) Production control is accurate: The present application can provide real-time feedback of volume density data, support immediate adjustment of raw material ratio or production process, and reduce the rate of defective products;

[0156] (3) Strong applicability: Compatible with experimental testing and theoretical calculation of two hydration water amount determination methods, suitable for different raw material stability and production scenarios under different technical conditions;

[0157] (4) High precision and reliability: The difference between the predicted value and the measured value is controlled within 3%, meeting the industry quality control standards.

[0158] In order to further understand the present application, the preferred embodiments of the present application are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present application, and are not limitations of the claims of the present application.

[0159] Example 1

[0160] The formula of the light plaster gypsum to be tested: gypsum powder 1: 40%, gypsum powder 2: 20%, heavy calcium powder: 30%, vitrified microbeads: 8%, additives: 2%.

[0161] 1. Test method

[0162] S1, obtain the proportion of gypsum hydration water consumption in the light plaster gypsum formula:

[0163] Test method:

[0164] Take gypsum powder 1 and gypsum powder 2 and mix them according to the ratio of the two in the light-weight plastering gypsum formula to be tested, as a gypsum powder sample. Take a certain amount of the gypsum powder sample and measure its mass a = 3.0003 g. Mix the above-mentioned gypsum powder sample with 3.0 g of water to obtain a slurry. Then, cure it at 20℃ for 2 h. After that, put it into a 50℃ oven and dry it to constant weight, with a drying time of 6 h. Test the dried mass a' = 3.4137 g. Calculate the water consumption ratio b% of the gypsum powder hydration by the following formula (I-1):

[0165] b% = (a' - a) / a x 100% = 13.78%.

[0166] S2, determine the standard consistency water requirement and test the wet density of the mixed slurry:

[0167] (S2a): determine the standard consistency water requirement w% of the light-weight plastering gypsum

[0168] According to test method GB / T 28627-2023 "Plastering Gypsum" 7.4.1, the standard consistency water requirement w% of the light-weight plastering gypsum to be tested is measured as 57.5%.

[0169] (S2b): test the wet density of the mixed slurry

[0170] First, take a certain amount of light-weight plastering gypsum and measure its mass m2 = 1000 g; combine the standard consistency water requirement w% of the previous step to calculate the required mixing water m3 = m2 x w% = 575 g, and take the corresponding mass of mixing water. Then, mix the light-weight plastering gypsum and the mixing water to form a uniform slurry; test the wet density p of the slurry 湿 = 1224 kg / m 3 .

[0171] S3, calculate the bulk density:

[0172] Calculate the bulk density p by the following formula (I-3):

[0173] p = p 湿 / (1 + w%) x (1 + C% x b%) = 841 kg / m 3 formula (I-3);

[0174] Wherein C% is the total content of gypsum powder in the light-weight plastering gypsum formula to be tested, which is 60%.

[0175] 2, precision

[0176] Repeat the test 6 times according to the method of Example 1, and the test results are shown in Table 1.

[0177] Table 1: Precision verification results of Example 1

[0178]

[0179] From the test results of the above table, it can be seen that the test method of the present application has a low relative standard deviation (RSD%) after multiple tests, proving that the test method of the present application has high precision and good repeatability.

[0180] 3. Accuracy

[0181] Test of measured value: The dry density of the above-mentioned to-be-tested light plaster gypsum was tested according to the test method in the standard GB / T 28627-2023, and the obtained result represents the measured value. The results show that the measured value obtained is p = 839 kg / m 3 .

[0182] Predicted value: The dry density result obtained by the test method of the present application is recorded as the predicted value. According to the test method of Example 1, it is repeated for 3 times, and the average value of the 3 test results is taken as the predicted value result (the 3 test results are 841 kg / m 3 , 844 kg / m 3 , 839 kg / m 3 ), the predicted value = 841 kg / m 3 .

[0183] Relative error = (predicted value - measured value) / measured value x 100% = 0.24%.

[0184] It can be seen that the error between the result obtained by the test method of the present application and the measured value is only 0.24%, which has high accuracy.

[0185] Example 2

[0186] To-be-tested light plaster gypsum formula: same as Example 1.

[0187] 1. Test method

[0188] S1, obtain the hydration water consumption proportion of the light plaster gypsum formula:

[0189] Calculation method:

[0190] Detect the phase composition of the gypsum powder 1 in the light plaster gypsum formula: the attached water content ω a1 = 0%, the content of III type anhydrous gypsum ω A1 = 1.2%, and the content of hemihydrate gypsum ω aHH1 = 68.2%. The phase composition of the gypsum powder 2: the attached water content ω a2 = 0%, the content of III type anhydrous gypsum ω A2 = 7.6%, and the content of hemihydrate gypsum ω aHH2= 74.8%. The incorporation amount C of each gypsum powder in the light plaster gypsum formula i The gypsum powder water consumption ratio b% is calculated by the following formula (I-2).

[0191]

[0192] S2, determining the standard consistency water content and testing the wet density of the mixed slurry: same as example 1.

[0193] S3, calculating the volume density:

[0194] The volume density p is calculated by the following formula (I-3):

[0195] p = p 湿 / (1 + w%) x (1 + C% x b%) = 842 kg / m 3 Formula (I-3).

[0196] 2, precision

[0197] The precision is verified according to the verification method in example 1, and the results are shown in table 2.

[0198] Table 2: precision verification results of example 2

[0199]

[0200] From the above table test results, it can be seen that the test method of the present application is repeated several times, and the relative standard deviation (RSD%) is low, which proves that the test method of the present application has high precision and good repeatability.

[0201] 3, accuracy

[0202] The accuracy is verified according to the verification method of example 1, and the results show that the relative error = (predicted value - measured value) / measured value x 100% = 0.36%.

[0203] It can be seen that the error between the results obtained by the test method of the present application and the measured value is only 0.36%, which has high accuracy.

[0204] Example 3

[0205] Take several batches of different light plaster gypsums, and test the dry density of each light plaster gypsum according to the test method in example 1. Then, the accuracy is verified according to the accuracy verification method of example 1. The test results (i.e. predicted value) obtained by the test method of the present application are taken as the abscissa, and the results (i.e. measured value) obtained according to the test standard are taken as the ordinate, and the graph is plotted, and the results are shown in Figure 1 . Figure 1In the figure, the scatter points are the graphs made, and the dashed line is the standard line y=x line (i.e. represents the ordinate = abscissa, measured value = predicted value), from the scatter point distribution, it can be seen that most of the scatter points are concentrated around the y=x line, that is, the predicted value of most test results is close to the measured value or even equal to the measured value, the linear regression equation thereof is y=1.0079x, the linear correlation coefficient R 2 =0.9999, it is proved that there is a very strong linear relationship between the predicted value and the measured value, and the relative error of all scatter points is less than 3% (ranging from-2.20% to 2.98%) as a whole, therefore, it is proved that the test method of the present application has very high accuracy.

[0206] In summary, it can be seen that the absolute value of the relative error of the test method of the present application and the standard test method is less than 3.0%, has high accuracy, and can accurately reflect the dry density of the light plastering gypsum. Moreover, the test method of the present application can be completed within 24h, which greatly saves the test time compared with the traditional standard test method (the traditional test method needs more than 7 days), the volume density data can be fed back in real time by using the method of the present application, the raw material ratio or the production process can be adjusted in real time, the unqualified product rate is reduced, and the problems of long cycle and poor timeliness of the traditional test method are overcome.

[0207] In this paper, specific examples are applied to explain the principles and implementation modes of the present application, the above embodiment descriptions are only used to help understand the method of the present application and its core idea, including the best mode, and also enable any person skilled in the art to practice the present application, including manufacturing and using any device or system, and implementing any combined method. It should be noted that, for ordinary skilled persons in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application. The scope of the patent protection of the present application is defined by the claims, and can include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for rapid evaluation of bulk density of lightweight plaster gypsum, characterized by, The method comprises the following steps: S1, obtaining the hydration water consumption ratio of the gypsum powder in the light plaster gypsum formula: The method for obtaining is selected from any one of the following (1) to (2): (1) test method: Take a certain amount of gypsum powder sample, measure its mass a; mix and maintain the gypsum powder sample with water, then dry to constant weight, record the mass a' at this time; calculate the hydration water consumption ratio b% of the gypsum powder by the following formula (I-1); b% = (a' - a) / a x 100% formula (I-1); The composition of the gypsum powder sample is the same as that of the gypsum powder in the light plaster gypsum formula; (2) calculation method: Assuming that the lightweight plaster gypsum formula contains n kinds of gypsum powder, record the mixing amount C of each kind of gypsum powder in the lightweight plaster gypsum formula i , determine the attached water content ω ai , type III anhydrous gypsum content ω Ai and hemihydrate gypsum content ω aHHi of each kind of gypsum powder; calculate the hydration water consumption proportion b% of the gypsum powder by the following formula (I-2) In the above (1) to (2), the hydration water consumption ratio b% of the gypsum powder is the percentage of the mass of water consumed by the complete hydration of the gypsum powder in the light plaster gypsum formula to the mass of the gypsum powder; S2, determine the standard consistency water requirement and test the wet density of the mixed slurry: (S2a): determine the standard consistency water requirement w% of the light plaster gypsum; (S2b): test the wet density of the mixed slurry: Take the light plaster gypsum, measure its mass as m2; calculate the required mixing water amount m3 = m2 x w%, and take the corresponding mass of mixing water; The light-weight plastering gypsum is mixed with mixing water to obtain a slurry; the wet density p of the slurry is tested 湿 , in kg / m 3 ​ S3, calculate the bulk density: The bulk density is calculated by any one of the following methods (1) to (2): Method (1): The method (1) comprises the following steps: (1.1) calculate the evaporation water amount: The percentage content of the gypsum powder in the light plaster gypsum formula is denoted as C%; The evaporation water amount W2 is calculated by the following formula (I-3X): W2 = p 湿 (1 + w%) x w% - p 湿 (1 + w%) x C% x b% Equation (I-3X); (1.2) calculate the bulk density: The bulk density p is calculated by the following formula (I-3Y): p = p 湿 - W2 formula (I-3Y); Method (2): The bulk density p is calculated by the following formula (I-3): p = p 湿 (1 + w%) x (1 + C% x b%) Equation (I-3).

2. The rapid evaluation method according to claim 1, characterized in that, In step S1, the mass ratio of the gypsum powder sample to water is 1: (0.5-1.0).

3. The rapid evaluation method of claim 1, wherein In step S1, the temperature condition for curing is (20±5)℃.

4. The rapid evaluation method of claim 1, wherein In step S1, the curing time is 1-3h.

5. The rapid evaluation method of claim 1, wherein In step S1, the drying temperature is 40-60℃.

6. The rapid evaluation method of claim 1, wherein In step S2, the wet density is measured by a density measuring tool.

7. The rapid evaluation method of claim 1, wherein The content of gypsum powder in the light plaster gypsum is ≥30%.

8. The rapid evaluation method of claim 1, wherein, In method (1) in step S1, the way of taking the gypsum powder sample comprises: If there is only one kind of gypsum powder in the light plaster gypsum formula, only this kind of gypsum powder is taken as the gypsum powder sample; If there are multiple kinds of gypsum powder in the light plaster gypsum formula, multiple kinds of gypsum powder are taken and matched according to the proportion between them in the light plaster gypsum formula as the gypsum powder sample.

9. The rapid evaluation method of claim 1, wherein, Method (1) in step S1 is also selected from the following methods: Assuming that the light stucco gypsum formula contains n kinds of gypsum powder, and the mixing amount of each gypsum powder in the light stucco gypsum formula is C i , respectively, take n kinds of gypsum powder and test their quality a i respectively; each kind of gypsum powder is mixed with water, cured, and then dried to constant weight, and the mass a i ′ at this time is recorded respectively; The water consumption ratio b of each gypsum powder is calculated by the following formula (I-1X)' and (I-1Y)' i %, and then the water consumption ratio b of the n kinds of gypsum powder is calculated by the following formula (I-1X)' and (I-1Y)' b i % = (a i ′ - a i ) / a i x 100% Formula (I-1X)' ; Among them, n≥1； C i represents the amount of the i-th gypsum powder in the light-weight plastering gypsum formulation, i = 1 to n.

10. The rapid evaluation method of claim 1, wherein The light plaster gypsum is LA type light plaster gypsum.

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