A method for measuring the content of SBS in SBS modified asphalt by using an atomic force microscope

Abstract

The application relates to a method for measuring the SBS content in SBS modified asphalt by using an atomic force microscope, and comprises the following steps: S1, preparing three kinds of SBS modified asphalt with known SBS content, and testing the nanometer scale microstructure morphology diagrams of the three kinds of asphalt; S2, measuring the long axis size a and the short axis size b of the honeycomb structure in the three kinds of morphology diagrams, and obtaining the size characteristic parameter indexes X1, X2 and X3 of the three kinds of morphology diagrams respectively; S3, testing the nanometer scale microstructure morphology diagram of SBS modified asphalt with unknown content, and calculating the size characteristic parameter index X of the honeycomb structure according to step S2 X ; S4, constructing a linear regression equation according to the size characteristic parameter indexes obtained in step S2; S5, inputting the size characteristic parameter index X X of the SBS modified asphalt with unknown content into the linear regression equation, and obtaining the content Y X of the SBS. Compared with the prior art, the method realizes the visualization and high-precision detection of the SBS content change in the SBS modified asphalt by using the intuitive test pictures and data in the nanometer scale.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of traffic and road engineering, and particularly relates to a method for measuring SBS content in SBS modified asphalt by using an atomic force microscope. BACKGROUND

[0002] At high temperature, light components in asphalt soften first and flow easily, i.e., poor deformation resistance; at low temperature, heavy components in asphalt are hard and brittle, and poor in crack resistance. Due to the temperature sensitivity of light and heavy components in asphalt, high-temperature anti-rutting deformation and low-temperature anti-cracking performance of asphalt mixture are a pair of contradictions, i.e., good high-temperature performance is relatively poor in low-temperature performance, and poor high-temperature performance is good in low-temperature performance.

[0003] SBS modifier can melt and solidify macromolecular chains in light and heavy components in asphalt, form a spatial network structure, and balance high and low temperature performance of asphalt, thereby significantly improving road performance of asphalt mixture, and making it widely used in high-grade asphalt pavement such as expressway.

[0004] The addition amount of SBS is not linearly related to the road performance of asphalt mixture, but has an optimal addition amount to make the road performance of asphalt mixture optimal in all aspects. At the same time, due to the fact that the price of SBS modifier is much higher than that of asphalt, a small change in the addition amount will have an important impact on the final cost of modified asphalt. In order to control the engineering cost, the optimal addition amount of SBS is often limited to a very small range.

[0005] At present, in order to reduce the engineering cost, the construction unit reduces the SBS addition amount and adds a small amount of toxic sulfur additive, which can ensure the high-temperature anti-rutting performance of asphalt pavement, but the low-temperature crack resistance is significantly deteriorated; or directly reduces the SBS addition amount, which greatly reduces the service life of asphalt pavement.

[0006] With more and more high-grade pavements such as urban expressways and urban elevated roads being built, and considering the difficulty of urban traffic restriction during construction and maintenance of asphalt pavement, the quality of asphalt pavement is increasingly valued.

[0007] Therefore, various detection technologies based on the molecular structure, relative molecular mass, and chemical properties of characteristic functional groups of SBS have been developed. However, due to their poor accuracy and cumbersome detection steps, infrared spectroscopy has become the main method for detecting SBS content in SBS-modified asphalt. A search of Chinese patent CN114739941A reveals a rapid detection method for SBS content based on a modified asphalt sample library. This method includes: preparing the sample to be tested and measuring its infrared spectrum; dividing the normalized infrared spectrum into characteristic spectral sets according to characteristic bands; calculating the matching degree between the characteristic spectral set of the sample to be tested and the characteristic spectral sets of all standard samples in the modified asphalt sample library; and calculating the characteristic area ratio and predicting the SBS content based on the comparison between the calculated maximum matching degree and a preset value, or further expanding the modified asphalt sample library.

[0008] Existing infrared spectroscopy detection technology only indirectly and abstractly explains the changes in SBS content by observing changes in the infrared absorption or reflection of the molecular structure surface, lacking intuitive images or data support. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art by providing a method for measuring the SBS content in SBS-modified asphalt using an atomic force microscope.

[0010] The objective of this invention can be achieved through the following technical solutions:

[0011] A method for measuring the SBS content in SBS-modified bitumen using atomic force microscopy includes the following steps:

[0012] S1. Three types of SBS-modified asphalt with known SBS content were prepared, and the nanoscale microstructure morphology of the three asphalts was tested based on atomic force microscopy.

[0013] S2. Measure the major axis dimension a and minor axis dimension b of the honeycomb structure in the three morphological images, and obtain the size characteristic parameters X1, X2 and X3 of the three morphological images respectively through formulas.

[0014] S3. Based on the size characteristic parameters obtained in step S2, construct a linear regression equation;

[0015] S4. The nanoscale microstructure morphology of SBS-modified asphalt with unknown content was examined using atomic force microscopy. Based on step S2, the size characteristic parameter X of the honeycomb structure was calculated. X ;

[0016] S5. The dimensional characteristic parameter X of SBS modified asphalt with unknown content. X Substituting into the linear regression equation, we obtain the SBS content Y. X .

[0017] Further, the step S2 utilizes the software of the instrument to measure the long axis size a and the short axis size b of the honeycomb structure in the three kinds of topography maps respectively, selects the honeycomb structure with the long axis size greater than 1.5 microns, and sequentially calculates X MN =a N / 3b N , X 11 , X 1N and X 21 according to the formula X 2N =a 31 / 3b 3N , and obtains the size characteristic parameter indexes X1, X2 and X3 respectively, wherein M represents the type of the asphalt, M=1, 2, 3, and N represents the number of parallel experiments.

[0018] Further, the step S3 constructs a linear regression equation with X1, X2 and X3 as the horizontal coordinate axes and Y1, Y2 and Y3 as the vertical coordinate axes.

[0019] Further, the step S4 utilizes the software of the instrument to measure the long axis size a and the short axis size b of the honeycomb structure in the nanometer scale microstructure topography map of the unknown content SBS modified asphalt, selects the honeycomb structure with the long axis size greater than 1.5 microns, and sequentially calculates X XN =a N / 3b N , X X1 , X XN and X X according to the formula X 11 =a 1N / 3b 21 .

[0020] Further, the size characteristic parameter indexes X1, X2 and X3 are the average values of X 2N , X 31 and X 3N .

[0021] Further, the SBS content Y X of the three kinds of SBS modified asphalts with known SBS content nonlinearly increases, and 1.0≤Y X ≤5.0.

[0022] Further, the software of the instrument is an analysis software with the precision of 0.1 nm.

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] 1. The present application is beneficial to the calculation of subsequent unknown content SBS modified asphalt by preparing three SBS modified asphalts with known SBS content, testing three nanoscale microstructure morphology maps of the asphalts based on atomic force microscopy, measuring the long axis size a and the short axis size b of the honeycomb structure in the three morphology maps, obtaining size characteristic parameter indexes X1, X2 and X3 of the three morphology maps, and constructing a linear regression equation.

[0025] 2. The present application is beneficial to the calculation of subsequent unknown content SBS modified asphalt by preparing three SBS modified asphalts with known SBS content, testing three nanoscale microstructure morphology maps of the asphalts based on atomic force microscopy, measuring the long axis size a and the short axis size b of the honeycomb structure in the three morphology maps, obtaining size characteristic parameter indexes X1, X2 and X3 of the three morphology maps, and constructing a linear regression equation. X , the size characteristic parameter index X X of the unknown content SBS modified asphalt is calculated according to step S2. X , the content Y X of SBS is obtained by bringing the size characteristic parameter index X X of the unknown content SBS modified asphalt into the linear regression equation. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The present application is a flowchart.

[0027] Figure 2 The present application is a nanoscale microstructure morphology characteristic parameter diagram. DETAILED DESCRIPTION

[0028] The present application will be described in detail below in combination with the drawings and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present application, and detailed implementation and specific operation processes are given, but the protection scope of the present application is not limited to the following examples.

[0029] As shown in the drawings, a method for measuring the content of SBS in SBS modified asphalt by atomic force microscopy comprises the following steps: Figure 1 S1, three SBS modified asphalts with known SBS content are prepared, and three nanoscale microstructure morphology maps of the asphalts are tested based on atomic force microscopy;

[0031] S2, the long axis size a and the short axis size b of the honeycomb structure in the three morphology maps are measured, and the size characteristic parameter indexes X1, X2 and X3 of the three morphology maps are obtained by the formula respectively;

[0032] S3, a linear regression equation is constructed according to the size characteristic parameter indexes obtained in step S2;

[0033] S4, the nanoscale microstructure morphology map of the unknown content SBS modified asphalt is tested by atomic force microscopy, and the size characteristic parameter index X X of the honeycomb structure is calculated according to step S2.

[0034] S5. The dimensional characteristic parameter X of SBS modified asphalt with unknown content. X Substituting into the linear regression equation, we obtain the SBS content Y. X .

[0035] In step S2, the major axis dimension 'a' and minor axis dimension 'b' of the honeycomb structures in the three morphological images are measured using the instrument's built-in software. Honeycomb structures with a major axis dimension greater than 1.5 μm are selected, and the results are calculated according to formula X. MN =a N / 3b N Calculate X sequentially 11 ...X 1N X 21 ...X 2N and X 31 ...X 3N The dimensional characteristic parameters X1, X2 and X3 were obtained respectively, where M represents the type of asphalt, M = 1, 2, 3, and N represents the number of parallel experiments.

[0036] In step S3, a linear regression equation is constructed with X1, X2, and X3 as the abscissa and the SBS content of the three known SBS modified asphalts Y1, Y2, and Y3 as the ordinate.

[0037] In step S4, the instrument's built-in software is used to measure the major axis dimension *a* and minor axis dimension *b* of the honeycomb structure in the nanoscale microstructure morphology image of SBS-modified asphalt with unknown content. Honeycomb structures with a major axis dimension greater than 1.5 μm are selected, and the results are calculated according to formula X. XN =a N / 3b N Calculate X sequentially X1 ...X XN And obtain the dimensional characteristic parameter index X X .

[0038] The dimensional characteristic parameters X1, X2, and X3 are respectively X 11 ...X 1N X 21 ...X 2N and X 31 ...X 3N The average value of the SBS content Y in three types of SBS-modified asphalt with known SBS content. X Nonlinear increase, and 1.0 ≤ Y X ≤5.0.

[0039] Example 1

[0040] A method for measuring SBS content in SBS modified asphalt by atomic force microscope, SBS content in SBS modified asphalt sample is 1%, 2.5% and 4.5% respectively.

[0041] Test their nanometer scale microstructure topography by atomic force microscope, determine size characteristic parameter index X1, X2 and X3 of honeycomb structure in nanometer scale microstructure topography of three known SBS content SBS modified asphalt.

[0042] Measure long axis size a and short axis size b of honeycomb structure in topography by Nanoscope Analysis software, select honeycomb structure with long axis size greater than 1.5 μm, calculate X MN ……X N N ……X 11 ……X 1N ……X 21 ……X 2N ……X 31 ……X 3N respectively according to formula X XN =a N / 3b N , and get size characteristic parameter index X1, X2 and X3 respectively, as follows:

[0043]

[0044] Take X1, X2 and X3 as abscissa axis, take Y1, Y2 and Y3 as ordinate axis, construct linear regression equation, as shown in formula (1). Figure 2

[0045] Measure long axis size a and short axis size b of honeycomb structure in nanometer scale microstructure topography of unknown content SBS modified asphalt by software, select honeycomb structure with long axis size greater than 1.5 μm, calculate X X1 ……X XN respectively according to formula X XN =a N / 3b N , and get size characteristic parameter index X X , as follows:

[0046]

[0047] Put X X =1.209% into linear regression equation, get SBS content Y X =3.73%.

[0048] The preferred embodiments of the present application have been described above in detail. It should be understood that modifications and variations to the present application can be affected by those skilled in the art without departing from the scope of the application. Accordingly, it is intended that all possible modifications and alterations be included within the scope of the present application as defined by the following claims.

Claims

1. A method for measuring the content of SBS in SBS modified asphalt using an atomic force microscope, characterized in that, It comprises the following steps: S1, preparing three SBS modified asphalts with known SBS contents, and testing the nano-scale microstructure topography of the three asphalts based on atomic force microscopy; S2, measuring the long axis size a and short axis size b of the honeycomb structure in the three topographies, and obtaining size characteristic parameter indexes X1, X2 and X3 of the three topographies respectively through a formula; S3, constructing a linear regression equation according to the size characteristic parameter indexes obtained in step S2; S4, using an atomic force microscope to test the nanoscale microstructure morphology of the unknown content SBS modified asphalt, and calculating the size characteristic parameter index X of the honeycomb structure according to step S2 X ; S5, size characteristic parameter index X of unknown content SBS modified asphalt X into the linear regression equation, get the content Y of SBS X ; In step S2, the major axis dimension 'a' and minor axis dimension 'b' of the honeycomb structures in the three morphological images are measured using the instrument's built-in software. Honeycomb structures with a major axis dimension greater than 1.5 μm are selected, and the results are calculated according to formula X. MN =a N / 3b N Calculate X sequentially 11 ...X 1N X 21 ...X 2N and X 31 ...X 3N The dimensional characteristic parameters X1, X2 and X3 were obtained respectively, where M represents the type of asphalt, M = 1, 2, 3, and N represents the number of parallel experiments; In step S3, X1, X2 and X3 are taken as the horizontal coordinate axes, and Y1, Y2 and Y3, the SBS contents of the three known SBS modified asphalts, are taken as the vertical coordinate axes, to construct the linear regression equation; In step S4, the long axis size a and the short axis size b of the honeycomb structure in the microstructure morphology graph of the unknown content SBS modified asphalt nanoscale are measured by using the software of the instrument, the honeycomb structure with the long axis size greater than 1.5 μm is selected, and the formula X XN = a N / 3b N is used to sequentially calculate X X1 ……X XN , and the size characteristic parameter index X X is obtained.

2. The method for measuring the content of SBS in SBS modified asphalt by atomic force microscope according to claim 1, characterized in that, The size characteristic parameter indicators X1, X2 and X3 are respectively X 11 … X 1N , X 21 … X 2N and X 31 … X 3N average value.

3. The method for measuring the content of SBS in SBS modified asphalt by using atomic force microscope according to claim 1, characterized in that, The SBS content Y in the three SBS modified asphalts with known SBS content X non-linearly increasing, and 1.0≤Y X ≤5.

0.

4. The method for measuring the content of SBS in SBS modified asphalt by using atomic force microscope according to claim 1, characterized in that, The software of the instrument itself is an analysis software with a precision of 0.1 mm.

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