Abstract

This study focuses on improving the performance of asphalt mixture at low- and high- temperature and analyzing the effect of diatomite and basalt fiber on the performance of the asphalt mixture. Based on the L16(45) orthogonal experimental design (OED), the content of diatomite (D) and basalt fiber (B) and the asphalt-aggregate (A) ratio were selected as contributing factors, and each contributing factor corresponded to four levels. Bulk volume density (γf), volume of air voids (VV), voids filled with asphalt (VFA), Marshall stability (MS) and splitting strength at −10 °C (Sb) were taken as the evaluation indexes. According to the results of the orthogonal experiment, the range analysis and variance analysis were used to study the effect of the diatomite content, basalt fiber content and asphalt-aggregate ratio on the performance of the asphalt mixture, and the grey correlation grade analysis (GCGA) was used to obtain the optimal mixing scheme. Furthermore, the performance tests were conducted to evaluate the performance improvement of asphalt mixtures with diatomite and basalt fibers, and the scanning electron microscopy (SEM) tests were carried out to analyze the mechanism of diatomite and basalt fibers in asphalt mixtures. The results revealed that the addition of diatomite and basalt fiber can significantly increase the VV of asphalt mixture, and reduce γf and VFA; the optimal performance of the asphalt mixture at high- and low-temperature are achieved with 14% diatomite, 0.32% basalt fibers and 5.45% asphalt-aggregate ratio. Moreover, the porous structure of diatomite and the overlapping network of basalt fibers are the main reasons for improving the performance of asphalt mixture.

Highlights

  • With the increase of the traffic in recent years, the pavement performance of the matrix asphalt mixture has been difficult to meet the requirement for long-term service of pavements

  • The results revealed that the rutting and stability of the asphalt mixture were improved by adding diatomite

  • Bulk volume density, volume of air voids (VV), voids filled with asphalt (VFA), Marshall stability (MS) and splitting strength at –10 ◦ C (Sb ) were used to determine the optimum content of diatomite and basalt fibers in the asphalt mixture and the optimum asphalt-aggregate ratio of the asphalt mixture

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Summary

Introduction

With the increase of the traffic in recent years, the pavement performance of the matrix asphalt mixture has been difficult to meet the requirement for long-term service of pavements. The results revealed that the rutting and stability of the asphalt mixture were improved by adding diatomite It can be found from the above that diatomite and basalt fiber can effectively enhance the performance of the asphalt mixture. Jia [18] noted that the compound addition of diatomite and basalt fibers could improve the resistance to rutting and water damage of recycled hot mix asphalt mixtures It can be seen from the previous studies that the combination of diatomite and basalt fiber can significantly enhance the performance of the asphalt mixture. Due to the different characteristics of diatomite and basalt fibers on the performance of asphalt mixtures, it is necessary to consider their volumetric properties, and the high- and low-temperature performance in the study of the optimum content of diatomite and basalt fiber in the asphalt mixture. This work could provide some references for the practical application of diatomite and basalt fiber in pavement engineering

Materials
Experimental Scheme
Rutting Tests and the Uniaxial Compression Creep Test
Splitting Tests and Three-Point Bending Test
Immersion Marshall Test and Freeze-Thaw Splitting Test
GCGA Algorithm
Range Analysis
D2 D3 D4 B1 B2 B3 B4 A1 A2 A3 A4
Variance Analysis
The trend of average correlation grade the level of each evaluation index:
Performance Verification
Resistance to Permanent Deformation at High-Temperature
Moisture Susceptibility
Analysis of Improvement Mechanism
Conclusions

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