Study on Linear Expansion Performance of AR-SMA-13 Rubber Asphalt Mixture in Marshall Test

Abstract

The compaction degree of asphalt mixture directly affects the tensile or compressive strength of pavement, given that high elastic crumb rubber exists in asphalt rubber mixtures and the characteristics of asphalt rubber mixtures are quite different from ordinary ones. Asphalt rubber mixture AR-SMA-13 was used in Marshall compaction tests with different crumb rubber contents, oil-stone ratios, fine control rates, and compaction work (frequency) to measure the heights of samples after compaction and cooling. The relationships between the linear expansion rate of Marshall samples and the above factors are analyzed, and the correlation between the linear expansion performance of asphalt rubber mixture and volume indicator is analyzed. Results show the following: (1) the linear expansion rate of the Marshall sample of the AR-SMA-13 asphalt rubber mixture increases logarithmically with the increase of rubber powder content; (2) the linear expansion rate of the Marshall samples grows linearly with a 0.075 mm increase in the passing rate of the composite material; (3) the mixture void fraction decreases and its linear expansion rate increases with the growth in compaction work; (4) the established linear expansion prediction model can effectively simulate the experimental data; and (5) larger value of compactness indicates greater linear expansion rate of the asphalt rubber mixture AR-SMA-13.