###### Abstract  
Infrared spectroscopy SBS asphalt-modifier content detection technology has been applied in practical projects, which can effectively ensure the quality of pavement engineering. If the composition ratio of modified asphalt is not clear, the accuracy of the test results will be affected, which is the disadvantage of conventional infrared spectroscopy detection methods. In this paper, the influence of different kinds of additives on the accuracy of the infrared spectrogram and SBS content test was analyzed, and the microscopic mechanism of the effect of additives on the accuracy of SBS modified asphalt content testing was uncovered. Meanwhile, the sample preparation technique was improved and the testing technique was optimized. Results demonstrate that the improved standard curve algorithm eliminates the effect of additives on test accuracy, and the effect of additives on test accuracy was eliminated by improving the standard curve algorithm. Without the addition of additives, the content of the modifier is accurately measured by simplifying the boundary conditions of the test technique. The preparation of samples by the dissolution method has more advantages than the tableting method and can be used as a new sample preparation technology. Improvements in sample preparation techniques and standard curve algorithms improve the safety, convenience, applicability, and accuracy of detection techniques. SBS asphalt-modifier content; infrared spectrum; additive; microscopic mechanism; algorithm improvement +
Footnote †: journal: Medical Science  
gel permeation chromatography method, thermal weightlessness method, and chemical titration method. Among them, the infrared spectrum method can quantitatively measure the content of SBS modifiers with the characteristics of accuracy, speed, and suitability for on-site testing in the construction project, which is currently the most widely used test method [8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19]. [PERSON] [20] combined the FTIR and HP-GPC tests to estimate the modifier content and obtained a linear regression model of the modifier content. [PERSON] [21] successfully measured the polymer content in asphalt by infrared spectrum and improved the infrared spectrum to be a method that can be employed for the quantitative analysis of rubber powder content. AASHTO [22] published a test standard for polymer content in asphalt. The Virginia Transportation Commission [23] confirmed that the FTIR test in the AASHTO standard specification can be used to study the polymer content in asphalt. Although the infrared spectrum is currently the most widely used test method, it still has limitations in some cases. The traditional SBS-modified asphalt uniformly disperses the SBS in the matrix asphalt by physical methods, such as stirring and shearing, which have no obvious chemical changes between SBS and asphalt, just physical mixing. Most types of SBS are thermodynamically incompatible with asphalt, so SBS segregation will occur when stirring is stopped [5]. The storage stability and service performance of SBS-modified asphalt can be improved by adding additives, such as stabilizers and compatibilizers during the mixing process, which make the chemical reactions such as cross-linking and branching between asphalt and SBS to form a network structure [24]. To ensure test accuracy, before the determination of SBS modifier content, it is necessary to fully know the material composition ratio of the sample to be tested and prepare the same asphalt standard sample to calculate the standard curve equation, but in the case of not fully understanding its ratio, it will often affect the accuracy of the test results. If some types of additives are ignored in the preparation of the standard sample, the accuracy of SBS modifier content determination will be influenced.