Research On Adaptability Of Vibrating Compaction To Porousasphalt Mixture

As a typical of skeleton-gap structure mixtures, the air void of porous asphalt mixture isusually around20%after compaction. The porous asphalt mixture pavement has excellentdrainage performance with low-noise. It can also significantly improve the safety of driving inthe rain. However, the noise reduction performance mainly depends on internal structure ofthe mixture, which is closely related with the compacting method. Different compactingmethods make discrepancy interior structures, which may affect the performance of mixture.Based on the microstructure perspective of porous asphalt mixture, this article analyzed thevibratory compaction as the main research line. The micromechanics characteristics forporous asphalt mixtures, key raw material selection method, vibration compactioncharacteristics, gradation optimization, road performance and compacting technology werestudied in depth. The achievementswere verified in laboratory experiment and the verificationtest that provide the theoretical guidance for the application of vibration compactiontechnology in the design and application of porous asphalt mixture.Through study of the composition and characteristics of porous asphalt mixture,combining with the existing research results at home and abroad, the technical standards ofcoarse aggregate and fine aggregate for porous asphalt mixture were suggested. For theeffects high sticky asphalt to porous asphalt mixture performance, based on AHP and fuzzymathematics theory, comprehensive evaluation model of factors that affect performance wasconstructed, the comprehensive evaluation index weight value of high viscosity modifiedasphalt was proposed, the comprehensive evaluation method of high-viscosity modifiedasphalt was established, and the modification schemes which are suitable for real engineeringwas selected optimizedly.Based on the microstructure characteristics of porous asphalt mixture and the discreteelement method, the non-continuous theoretical model that can reflect the movement ofparticles in porous asphalt mixture was constructed. Combined with uniaxial penetration testin the way of numerical virtual simulations, the influenceof Compacting method and materialparameters on microstructure perspective of porous asphalt mixture were analyzed. By adopting vibrating compacting method, increasing bitumen viscosity and improving surfacecharacteristics, homogenizing the internal stress distribution in the mixture can improve thedeformation resistance of the porous asphalt mixture.Analyzing the relationship between the compaction characteristics of vibratory roller anddynamic properties of surface vibration compaction instrument, the vibration energyconsumption equation of the surface vibration compactor was deduced:E K1A0fM gT.Using a vibrating compactor, the effect of the law that line pressure, frequency, amplitude onporous asphalt mixture compaction were systematically studied. Combined with orthogonalgray relational analysis, the configuration factors of primary and secondary order whichinfluence the performances of the porous asphalt mixture is: angle> frequency> on and off thecounterweight, as well as the optimal vibration parameters combination: H35J120S4X5.By using pavement vibration compactor and the experiments of vibration andalternativein classification, the drainage asphalt mixture gradation had been optimizated. Theresearch got the conclusions as follows: the vibratory compaction state boundaries sieveaggregate size for porous asphalt mixture is4.75mm, the composition of different coarse andfine aggregates has optimized, the composed of the best ratio deduced reflect stable coarseaggregate skeleton microscopic characteristics of coarse aggregate strength index and thevolume indicator different nature of the components (including density, content andequivalent radius) relations coarse aggregate shear modulus ratio GR (vibratory compactionstate mixture of coarse aggregate shear modulus tamping plug fitted with dry coarse aggregatestate of the shear modulus) were deduced.Based on the optimized gradation for porous asphalt mixture, the effects of differentfactors on pavement performance were studied in a systematic way.The results show that thevibrating compaction and rubbing compaction are better than Maxell compaction at formingthe interlocking framework of porous asphalt mixture; and the dynamic stability value ofvibrating compaction specimens are1.532times of pressure shaping one.Trough verification test and pavement construction, the influence of vibratingcompaction craft on the porous asphalt mixture was studied. The results show that withincertain vibrating compaction times, the porous asphalt mixture gradation won’t change much more, and the vibrating compaction craft for porous asphalt mixture is optimized: at first, a12t twin steel wheel vibration roller vibrating rolls the asphalt mixture in a highfrequency-low amplitude way for3times, then a twin steel wheel vibration roller over11tpressure rolls for2times to eliminate the wheel path, and the two crafts should be compactconvergence.