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ABSTRACT To investigate the performance of asphalt mixture designed by the vertical vibration method, the vertical vibration design method (VTM design method) and Marshall design method were used to design [...]

ABSTRACT Volumetric properties, such as volume of air voids (VV), voids filled with asphalt (VFA), and voids in mineral aggregate (VMA), strongly influence the performance of asphalt mixtures. This paper [...]

In this study, the effects of virgin aggregate content, such as mineral filler, machine-made sand, and coarse aggregate, on the performance of emulsified asphalt cold recycled mixtures (ECRMs) produced using the vertical vibration compaction method (VVCM) are evaluated. The optimum virgin aggregate contents are proposed based on the results. The results show that with increasing mineral filler content (mass fraction <5%), the mechanical strength, rutting resistance and crack resistance of the ECRMs gradually increase, whereas the moisture sensitivity increases initially but gradually decreases, and 3% mineral filler demonstrates the optimum moisture sensitivity compared to reclaimed asphalt mixtures. Further, as machine-made sand content increases, the mechanical strength, rutting resistance, crack resistance and moisture sensitivity of the ECRMs increase initially and decrease gradually, and the aforementioned performance of the ECRMs reaches the peak values when 20% machine-made sand is added, compared to mixtures without the machine-made sand. The mechanical strength, rutting resistance, crack resistance and moisture sensitivity of the ECRMs initially increase and then gradually decrease with the addition of the coarse aggregate. When the coarse aggregate content is 10%–30%, the ECRMs show a good performance, compared to mixtures without the coarse aggregate. To effectively improve the engineering properties of the ECRMs, the proposed optimum content of the mineral filler, machine-made sand and coarse aggregate are 3%, 20% and 10–30%, respectively.

In this work, the flexural tensile fatigue behaviours of AC-20 asphalt mixtures were studied using beams, which were designed by the vertical vibration method (VVTM) and Marshall method. Then an analysis of variance (ANOVA) was used to examine the differences in fatigue lives, and the Weibull distribution was used to analyze the fatigue lives and establish the fatigue equations of the mixtures. Subsequently, the fatigue lives were compared and analyzed under the same stress level and repeated load force. The results showed that the test accuracy of specimens produced using the vertical vibration compaction method (VVCM) exceeds 92%. Compared to the Marshall design, the asphalt mixture fabricated with the VVTM design improved crack resistance and rutting resistance by at least 40% and 30%, respectively. The ratio of the slopes (the values of the regression coefficient b) of fatigue equations of asphalt mixtures designed by the VVTM to that of Marshall method ranges from 0.883 to 0.965, and the ratio of the intercepts (the values of the regression coefficient a) ranges from 1.278 to 1.284. The results also showed that compared to the Marshall design, asphalt mixtures fabricated with VVTM design exhibited improved fatigue lives by at least 61% (at a stress level of 0.45) and 356% (with a repeated load force of 0.378 kN).