Method for determining maximum accumulation rate of particles in emulsified asphalt drying process
By analyzing the emulsified asphalt drying process in stages and calculating the maximum particle accumulation rate, the shortcomings in the evaluation of emulsified asphalt drying performance and film forming performance in the existing technology are solved, and the scientific evaluation of emulsified asphalt drying and film forming performance is achieved, and the improvement of the Its adhesion and viscoelasticity.
Patent Information
- Application Number
- CN202411056423.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-02
- Publication Date
- 2024-12-20
AI Technical Summary
The prior art lacks scientific methods to evaluate the drying properties and film-forming properties of emulsified asphalt, which affects the effective control of the quality of emulsified asphalt.
The relationship curve between the water loss rate per unit area and the drying time was obtained through the film drying experiment, which was divided into three stages: rapid drying, slow drying and slow drying. The time point and water loss of the maximum accumulation rate of particles during the drying process were determined, and a linear simula was used to determine the time point and water loss. The maximum accumulation rate of particles in the emulsified asphalt drying process was calculated.
A scientific evaluation of the drying and film-forming properties of emulsified asphalt has been achieved, which can effectively control the drying speed and film-forming structure of emulsified asphalt, and improve its adhesion and viscoelasticity.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of emulsified asphalt quality evaluation, and specifically relates to a method for determining the maximum accumulation rate of particles in an emulsified asphalt drying process. Background Art
[0002] Emulsified asphalt is a material widely used in new construction, preventive maintenance and regeneration of asphalt pavement, including bonding transition layer technologies for new pavement such as tack coat and penetration coat, emulsified asphalt preventive technologies such as slurry seal, micro-surfacing, sand-containing fog seal, and emulsified asphalt cold regeneration / cold mix technology. The quality of emulsified asphalt greatly affects the application level of these pavement materials, so how to ensure the quality of emulsified asphalt is the key to the construction quality of such pavement materials.
[0003] During use, emulsified asphalt undergoes a drying and film-forming process in which water evaporates, asphalt particles are closely packed together, and emulsions break to form a continuous asphalt film. The drying process greatly affects the speed of recovery of the adhesion of the emulsified asphalt, and the asphalt film structure formed after drying greatly affects the final adhesion and viscoelasticity of the emulsified asphalt. Therefore, the drying performance and film-forming performance of emulsified asphalt are important technical properties of emulsified asphalt. An ideal emulsified asphalt should have the characteristics of fast drying speed and strong adhesion after drying. However, there is no scientific evaluation method for the drying performance and film-forming performance of emulsified asphalt in the current specifications, nor is there a corresponding direct or indirect evaluation index. It is still impossible to effectively evaluate the drying and film-forming quality of emulsified asphalt, which in turn affects the effective control of the quality of emulsified asphalt.
[0004] The tightly packed state of asphalt particles formed during the drying process of emulsified asphalt greatly affects the drying performance and film-forming performance of emulsified asphalt. The greater the maximum packing rate of particles during the drying process of emulsified asphalt, the higher the water evaporation rate of emulsified asphalt can be to dry to a state with a lower residual water content, thereby greatly shortening the drying process of emulsified asphalt; at the same time, the greater the maximum packing rate of particles, the fewer internal pores caused by evaporating water, the denser the emulsified asphalt film-forming structure, and the better the film-forming performance. Therefore, the maximum packing rate of particles during the drying process of emulsified asphalt can be used to uniformly and scientifically evaluate the drying and film-forming performance of emulsified asphalt. Summary of the invention
[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for determining the maximum stacking rate of particles in the emulsified asphalt drying process.
[0006] To achieve the above object, the present invention provides the following technical solution: a method for determining the maximum accumulation rate of particles in the emulsified asphalt drying process, the steps of which are:
[0007] (1) Obtaining the relationship curve between the water loss rate per unit area and the drying time, and the relationship curve between the water loss per unit area and the drying time through the film drying experiment;
[0008] (2) According to the relationship between the water loss rate per unit area and the drying time, the drying process is divided into three drying stages, namely, the rapid drying stage, the deceleration drying stage and the slow drying stage. At the same time, the dividing point between the rapid drying stage and the deceleration drying stage is determined as the point where the drying speed decreases significantly, and the dividing point between the deceleration drying stage and the slow drying stage is determined as the time point when the water loss rate decreases to about 5% of the average water loss rate in the rapid drying stage;
[0009] (3) According to the determined dividing points of the three drying stages, combined with the relationship curve between the water loss per unit area and the drying time, the three-stage drying curve of the water loss mass per unit area is obtained, and the fitting lines of the fast drying stage and the slow drying stage are obtained by linear fitting. Then, the intersection of the two fitting straight lines is obtained, which is the drying time point when the asphalt particles in the emulsified asphalt reach the maximum accumulation state;
[0010] (4) Based on the obtained drying time point of the maximum particle stacking rate, the unit area water loss of the emulsified asphalt at the moment when the particle maximum stacking rate is reached is accurately obtained according to the curve of unit area water loss mass and drying time in the deceleration drying stage;
[0011] (5) Based on the water loss per unit area when the emulsified asphalt reaches the maximum particle accumulation rate m tW The maximum accumulation rate of particles in the emulsified asphalt drying process is calculated by the formula m .
[0012] In some embodiments, according to step (5), the specific calculation formula is:
[0013]
[0014] The meanings of the parameters in formula (1) are as follows:
[0015] γ A ——is the specific gravity of asphalt;
[0016] m A ——The mass of asphalt per unit area in the emulsified asphalt sample;
[0017] m W ——The initial water mass per unit area in the emulsified asphalt sample;
[0018] m l,m ——The amount of water loss per unit area when the emulsified asphalt reaches the maximum particle accumulation rate.
[0019] In some embodiments, the asphalt mass per unit area in the emulsified asphalt sample is m A and the initial water mass per unit area in the emulsified asphalt sample m W The mass of the emulsified asphalt sample M AE , initial solid content of emulsified asphalt P A And the sample evaporation surface area S is calculated and determined.
[0020] In some embodiments, the specific calculation method is:
[0021]
[0022]
[0023] In some of the embodiments, according to step (1), in the emulsified asphalt drying test, the drying temperature is selected to be 15-30°C.
[0024] In some of the embodiments, the initial thickness of the emulsified asphalt sample is selected to be 2-6 mm.
[0025] In some of the embodiments, the initial solid content of the emulsified asphalt is diluted to 40%-50%.
[0026] Compared with the prior art, the beneficial effects of the present invention are: through the determination method of the present application, the drying and film-forming properties of emulsified asphalt are scientifically evaluated, and the drying and film-forming properties of emulsified asphalt are uniformly and scientifically evaluated through the maximum stacking rate of particles in the emulsified asphalt drying process.
[0027] Details of one or more embodiments of the present application are presented in the following drawings and descriptions to make other features, purposes and advantages of the present application more concise and easy to understand. The present application is fully described and understood through the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 A method for distinguishing the demarcation point of the drying stage based on the water loss rate curve per unit area of emulsified asphalt;
[0029] Figure 2 A method for obtaining the maximum particle stacking rate moment and the corresponding water loss based on the water loss per unit area curve of emulsified asphalt. DETAILED DESCRIPTION
[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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.
[0031] See also Figure 1-2 The present invention provides a technical solution: a method for determining the maximum accumulation rate of particles in the emulsified asphalt drying process, the steps of which are:
[0032] (1) Obtaining the relationship curve between the water loss rate per unit area and the drying time, and the relationship curve between the water loss per unit area and the drying time through the film drying experiment;
[0033] (2) According to the relationship between the water loss rate per unit area and the drying time, the drying process is divided into three drying stages, namely, the rapid drying stage, the deceleration drying stage and the slow drying stage. At the same time, the dividing point between the rapid drying stage and the deceleration drying stage is determined as the point where the drying speed decreases significantly, and the dividing point between the deceleration drying stage and the slow drying stage is determined as the time point when the water loss rate decreases to about 5% of the average water loss rate in the rapid drying stage;
[0034] (3) According to the determined dividing points of the three drying stages, combined with the relationship curve between the water loss per unit area and the drying time, the three-stage drying curve of the water loss mass per unit area is obtained, and the fitting lines of the fast drying stage and the slow drying stage are obtained by linear fitting. Then, the intersection of the two fitting straight lines is obtained, which is the drying time point when the asphalt particles in the emulsified asphalt reach the maximum accumulation state;
[0035] (4) Based on the obtained drying time point of the maximum particle stacking rate, the unit area water loss of the emulsified asphalt at the moment when the particle maximum stacking rate is reached is accurately obtained according to the curve of unit area water loss mass and drying time in the deceleration drying stage;
[0036] (5) Based on the water loss per unit area when the emulsified asphalt reaches the maximum particle accumulation rate m tW The maximum accumulation rate of particles in the emulsified asphalt drying process is calculated by the formula m .
[0037] According to step (5), the specific calculation formula is:
[0038]
[0039] The meanings of the parameters in formula (1) are as follows:
[0040] γ A ——is the specific gravity of asphalt;
[0041] m A ——The mass of asphalt per unit area in the emulsified asphalt sample;
[0042] m W ——The initial water mass per unit area in the emulsified asphalt sample;
[0043] ml,m ——The amount of water loss per unit area when the emulsified asphalt reaches the maximum particle accumulation rate.
[0044] The mass of asphalt per unit area in the emulsified asphalt sample is m A and the initial water mass per unit area in the emulsified asphalt sample m W The mass of the emulsified asphalt sample M AE , initial solid content of emulsified asphalt P A And the sample evaporation surface area S is calculated and determined.
[0045] The specific calculation method is:
[0046]
[0047]
[0048] According to step (1), in the emulsified asphalt drying test, the drying temperature is selected to be 15-30°C.
[0049] The initial thickness of the emulsified asphalt sample was selected to be 2-6 mm.
[0050] The initial solid content of emulsified asphalt is diluted to 40%-50%.
[0051] Through the technical solution of this application,
[0052] During the drying process of emulsified asphalt, the particle state changes from loose distribution, close accumulation, and demulsification to form a continuous asphalt film. The evaporation rates in the three stages are very different. When the asphalt particles are loosely distributed, the emulsified asphalt has a very high and relatively stable drying rate; in the stage of demulsification to form a continuous asphalt film, the drying rate of the emulsified asphalt is extremely low; and when the asphalt particles are close to close accumulation, the drying rate of the emulsified asphalt drops rapidly. Therefore, according to the drying rate of emulsified asphalt, the drying process of emulsified asphalt can be clearly divided into three stages, and the time point and water loss corresponding to the maximum accumulation rate of particles in the drying process of emulsified asphalt can be found, so as to calculate the maximum accumulation rate of emulsified asphalt particles.
[0053] Specifically, the solid content of the emulsified asphalt is first tested, and the solid content of the emulsified asphalt is diluted to 40% or 50%. Then, the specified mass of emulsified asphalt is added according to the diameter of the drying disc, the density of the emulsified asphalt, and the thickness of the sample. The water loss of the emulsified asphalt is tested every half an hour using a one-thousandth balance, and converted into the water loss per unit area and the water loss rate per unit area by formula (4) and formula (5), so as to draw the relationship curve between the water loss rate per unit area and the drying time and the relationship curve between the water loss per unit area and the drying time, as shown in FIG. Figure 1 and Figure 2 shown.
[0054]
[0055]
[0056] The meanings of the parameters in formula (4) and formula (5) are as follows:
[0057] M l,i ——Emulsified asphalt sample at drying time t i Total water loss at 100 ℃
[0058] m l,t ——Emulsified asphalt sample at drying time t i Total water loss per surface area at ;
[0059] ——Emulsified asphalt sample at drying time t i-1 and t i The water loss rate per unit area between;
[0060] S——dry surface area of emulsified asphalt sample;
[0061] pass Figure 1 The relationship curve between the water loss rate per unit area and the drying time shown in the figure can directly find the point where the drying rate drops significantly, which is used as the dividing point between the rapid evaporation stage and the deceleration evaporation stage, and is recorded as dividing point 1; at the same time, the time point when the water loss rate drops to about 5% of the average water loss rate in the rapid drying stage is found, which is used as the dividing point between the deceleration evaporation stage and the slow evaporation stage, and is recorded as dividing point 2.
[0062] Then, if Figure 2 As shown, the linear fitting method is used to fit the relationship between the water loss per unit area and the drying time in the fast drying stage and the slow drying stage, and the time point corresponding to the maximum stacking rate of the emulsified asphalt particles is obtained;
[0063] According to the curve of water loss per unit area and drying time in the deceleration drying stage, the water loss per unit area when the emulsified asphalt reaches the maximum particle accumulation rate can be accurately obtained;
[0064] Finally, the water loss per unit area when the emulsified asphalt reaches the maximum particle packing rate can be calculated using formula (1) to obtain the maximum particle packing rate.
[0065] Based on the above implementation scheme, for one of the emulsified asphalts, the complete drying process of the emulsified asphalt sample was tested according to the above test and data processing method, and the maximum accumulation rate of the emulsified asphalt particles was calculated. The results are shown in Table 1. As can be seen from Examples 1-4 in Table 1, within the test temperature range of 15-30°C, although the test temperature has a great influence on the drying speed of the emulsified asphalt in the first stage, it has a great influence on the maximum accumulation rate of the emulsified asphalt particles φ mIt can be seen from Examples 3 and 5-8 in Table 1 that within the sample thickness of 2-6 mm, although the different sample thicknesses have a great difference in the amount of water evaporated from the emulsified asphalt and the drying time, the maximum accumulation rate of the emulsified asphalt particles φ m It can be seen from Examples 3 and 9 that within the initial solid content range of 40%-50%, although the amount of water evaporated from the emulsified asphalt samples and the drying time vary greatly at different initial solid contents, the maximum stacking rate of the emulsified asphalt particles φ m These results show that the maximum particle accumulation rate determination method and range of the present invention can be used to determine the maximum particle accumulation rate of the particle. m Relatively stable.
[0066] Table 1
[0067]
[0068] Note: d0 represents the initial thickness of the sample, T is the drying temperature, is the average drying rate in the first stage.
[0069] Drying experiments were conducted on 5 different emulsified asphalt samples, and the maximum packing rate of emulsified asphalt particles was calculated by the above method. The drying conditions were: sample thickness 3mm, drying temperature 25℃, and initial solid content of emulsified asphalt 40%. At the same time, the dynamic modulus of the completely dried emulsified asphalt samples at 25℃ was tested by a dynamic shear rheometer, and the bonding strength of the completely dried emulsified asphalt samples with polished basalt aggregate at 25℃ was tested by a puller to characterize the film-forming properties of 5 different emulsified asphalts. The results are shown in Table 2. As can be seen from Table 2, the higher the maximum packing rate of the particles, the smaller the residual water content after drying for 24 hours, and the greater the dynamic modulus and adhesion strength of the residue after complete drying, which shows that the maximum packing rate of the particles can simultaneously reflect the advantages and disadvantages of drying performance and film-forming performance.
[0070] Table 2
[0071]
[0072] The above embodiments only express several implementation methods of the present application, 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 a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.
[0073] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A method for determining the maximum accumulation rate of particles in an emulsified asphalt drying process, characterized in that: The steps are: (1) Obtaining the relationship curve between the water loss rate per unit area and the drying time, and the relationship curve between the water loss per unit area and the drying time through the film drying experiment; (2) According to the relationship between the water loss rate per unit area and the drying time, the drying process is divided into three drying stages, namely, the rapid drying stage, the deceleration drying stage and the slow drying stage. At the same time, the dividing point between the rapid drying stage and the deceleration drying stage is determined as the point where the drying speed decreases significantly, and the dividing point between the deceleration drying stage and the slow drying stage is determined as the time point when the water loss rate decreases to about 5% of the average water loss rate in the rapid drying stage; (3) According to the determined dividing points of the three drying stages, combined with the relationship curve between the water loss per unit area and the drying time, the three-stage drying curve of the water loss mass per unit area is obtained, and the fitting lines of the fast drying stage and the slow drying stage are obtained by linear fitting. Then, the intersection of the two fitting straight lines is obtained, which is the drying time point when the asphalt particles in the emulsified asphalt reach the maximum accumulation state; (4) Based on the obtained drying time point of the maximum particle stacking rate, the unit area water loss of the emulsified asphalt at the moment when the particle maximum stacking rate is reached is accurately obtained according to the curve of unit area water loss mass and drying time in the deceleration drying stage; (5) Based on the water loss per unit area when the emulsified asphalt reaches the maximum particle accumulation rate m tW The maximum accumulation rate of particles in the emulsified asphalt drying process is calculated by the formula m .
2. The method for determining the maximum accumulation rate of particles in the emulsified asphalt drying process according to claim 1, characterized in that: According to step (5), the specific calculation formula is: The meanings of the parameters in formula (1) are as follows: γ A ——is the specific gravity of asphalt; m A ——The mass of asphalt per unit area in the emulsified asphalt sample; m W ——The initial water mass per unit area in the emulsified asphalt sample; m l,m ——The amount of water loss per unit area when the emulsified asphalt reaches the maximum particle accumulation rate.
3. The method for determining the maximum accumulation rate of particles in the emulsified asphalt drying process according to claim 2, characterized in that: The mass of asphalt per unit area in the emulsified asphalt sample is m A and the initial water mass per unit area in the emulsified asphalt sample m W The mass of the emulsified asphalt sample M AE , initial solid content of emulsified asphalt P A And the sample evaporation surface area S is calculated and determined.
4. The method for determining the maximum accumulation rate of particles in the emulsified asphalt drying process according to claim 3, characterized in that: The specific calculation method is:
5. The method for determining the maximum accumulation rate of particles in the emulsified asphalt drying process according to claim 1, characterized in that: According to step (1), in the emulsified asphalt drying test, the drying temperature is selected to be 15-30°C.
6. The method for determining the maximum accumulation rate of particles in the emulsified asphalt drying process according to claim 5, characterized in that: The initial thickness of the emulsified asphalt sample was selected to be 2-6 mm.
7. A method for determining the maximum accumulation rate of particles in an emulsified asphalt drying process according to claim 5 or 6, characterized in that: The initial solid content of emulsified asphalt is diluted to 40%-50%.