Search

To reduce asphalt pavement temperature and improve its anti-rutting performance in summer, thermally resistant friction course (referred to as TRFC-13), heat-reflective coating (referred to as HRC) and thermally resistant and heat-reflective coating integrated pavement (referred to as TR-HRC) were developed, and their cooling effect, anti-rutting performance and durability were evaluated. In addition, machine-made sands were applied to improve the anti-skid performance of the coating. The results show that compared with ordinary SMA-13 samples, the surface temperature of the TRFC-13, HRC and TR-HRC samples decreased by approximately 6.8°C, 11.2°C and 13.2°C, respectively. At the air temperature of approximately 40°C, the field road surface temperature of the TRFC-13, HRC and TR-HRC decreased by approximately 7.4°C, 12.2°C and 14.0°C, respectively. The higher the air temperature is, the better the anti-rutting performances of these three kinds of pavement. At the air temperature of 39°C, the dynamic stability of the TRFC-13, HRC and TR-HRC is 1.56 times, 1.86 times and 1.88 times that of the ordinary SMA-13, respectively. The results also show that HRC has a strong abrasion resistance and that spreading 40 wt% of machine-made sands can ensure the coatings achieve the best British Pendulum Number, without influencing its cooling performance. [ABSTRACT FROM AUTHOR]

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 analyzes the influence of volumetric properties on the mechanical properties of the ATB-30 asphalt mixture which molds using vertical vibration compaction method (VVCM). Suggested values of volumetric properties were proposed based on the optimization of mechanical properties. Additionally, the proposed design was evaluated based on its performance in practice. Results show a 92% testing accuracy of the mechanical properties of VVCM specimens. This accuracy reveals that the vibration molding is compatible with the mechanism of the roller. High consistency was observed between the mechanical properties of the ATB-30 asphalt mixture and VV, VFA. However, the correlation between mechanical properties and VMA was poor. Hence, the suggested values of VV and VFA in the ATB-30 asphalt mixture are 2.8%–4.0% and 64%–74%, respectively, and VMA is only used as a reference with a value of at least 10.5%. Compared with the Marshall Compaction method (MCM), the Marshall stability, dynamic stability, splitting strength, and tensile strength of the ATB-30 asphalt mixture increased by 54.4%, 39.1%, 54.8%, and 53.7%, respectively, when using the design-suggested values of the VVCM design. The water stability of the asphalt mixture also improved. [ABSTRACT FROM AUTHOR]

This study investigates the resilient modulus of vertical vibration compacted cement-stabilized macadam (CSM). The reliability of the vertical vibration compaction method (VVCM) for CSM was verified. Then the influences of four factors on the resilient modulus were studied and a resilient modulus prediction equation was proposed. Subsequently, the influences of aggregate type, cement dosage, and gradation on the initial and ultimate resilient moduli were studied. Results show that compared to the quasi-static-compaction method, the VVCM has a smaller influence on the optimum water content and aggregate gradation, and VVCM specimens have a higher correlation with the on-site cores. The increase of cement dosages and curing times can improve the resilient modulus and the proposed prediction equation can accurately predict the resilient modulus growth of the CSM. When the cement dosage and aggregate gradation are identical, the initial and ultimate resilient moduli of the cement-stabilized limestone are the largest, followed by the cement-stabilized granite and sandstone. The initial and ultimate resilient moduli of the CSM increase linearly as the cement dosage increases. Moreover, the skeleton-dense gradation helps to improve the initial and ultimate resilient moduli of the CSM. This study provides guidance for the design and construction of a CSM base. [ABSTRACT FROM AUTHOR]

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 the AC-16 (asphalt concrete with nominal maximum aggregate size = 16 mm) asphalt mixture. The physical properties, mechanical properties, road performance and fatigue property of the asphalt mixture designed by these two methods were examined. The results show that compared with that of the Marshall method, the optimal asphalt content of the asphalt mixture designed by the VTM method is decreased by 9.0%, and the density is increased by 1.8%; the mechanical properties, anti-rut ability and anti-crack ability are increased by at least 30%, 34% and 17%, respectively; and the water stability is also improved slightly. In addition, the fatigue life can be increased by at least 59%. The results also show that the Marshall stability, compression strength, splitting strength, tensile strength and shear strength of field drill cores designed by the VTM method are increased by at least 42%, 32%, 21%, 31% and 33%, respectively, compared with those of the Marshall method. Clearly, the performance of the asphalt mixture designed by the VTM method is better than that of the Marshall method, which could offer a better choice for asphalt mixture design. [ABSTRACT FROM AUTHOR]