Research Of The Pavement Performance Of Stone Matrix Asphalt Mixtures Using Basalt And Limestone Aggregates

Due to its high strength, Basalt is one of the most ideal aggregates for asphalt road surface, particularly SMA high-grade road surface. However, it is relatively high in cost, and is rare in some regions, which will cause much transportation fee, so it has engineering significance to replace basalt entirely or partially with limestone in paving SMA road surface.This project designs three kinds of combination to study the SMA-13asphalt mixture:basalt aggregate SMA, limestone aggregate SMA, and basalt and limestone aggregate SMA. The physical properties of the raw material in three kinds of aggregate SMA, the influence of the aggregate on the volume index of SMA mixture, and the pavement performance and mechanical performance of the three kinds of aggregate SMA are systematically studied.The physical and mechanical performance test of basalt and limestone shows that the strength of limestone is less than that of the basalt, and the two types of aggregates are different in their adherence to asphalt. The limestone aggregate has better adherence to asphalt than the basalt aggregate. By analyzing basalt and limestone’s difference in surface texture and chemical composition, the study explains the said difference of adhesion from the aspect of mechanism.By studying the volume index in grading design of asphalt mixture, it is found that the aggregate SMA of basalt and limestone are different in volume index under the same gradation and oil-stone ratio. This difference is analyzed from the aspect of mechanism:first, the needle flake particle concentration in coarse aggregate is different; second, the strength of the aggregate is different, which leads to the fact that under the same compaction force, the surface of limestone can be partially broken, while basalt specimens have no such phenomenon.Through low-temperature beam bending test, rutting test, creep test, freeze-thaw splitting test and dynamic modulus test, the study examines the pavement performance and mechanical properties of the three kinds of aggregate SMA. It is concluded that, in the aspect of high temperature performance, the three kinds of aggregate SMA are ranked as follows:basalt aggregate SMA> basalt and limestone mixed aggregate SMA> limestone aggregate SMA; in the aspect of water stability, they are ranked as follows:limestone aggregate SMA> basalt and limestone mixed aggregate SMA> basalt aggregate SMA; in the aspect of low temperature performance, they are ranked as:limestone aggregate SMA> basalt and limestone mixed aggregate SMA> basalt aggregate SMA; and, their dynamic modulus under the same frequency and temperature are ranked as follows:basalt aggregate SMA> basalt and limestone mixed aggregate SMA> limestone aggregate SMA.By integrating the high temperature performance, low temperature performance, water stability and mechanical performance of the SMA asphalt mixture, the basalt and limestone mixed aggregate SMA has its overall performance improved, so it is a relatively ideal combination scheme.