公路施工新技术,2004年12月,施工过程新技术,自检碾压机 移动式拌和楼 红外线摄影机 混合料传送机,不均匀密度的影响,同压密不够类似 增加剥落与水损 减少疲劳寿命 增加空隙率1%将至少减少10%的寿命,不均匀密度的位置,温差超过14C 空隙率增加2%,材料传递机,材料传递机 拌和叶片,摊铺之前的 再拌和,施工工艺自动化,计算机技术应用 卫星和激光定位技术 遥控技术 图控技术 机器眼技术 动态反馈和传感技术 人机对话技术,卫星定位技术,激光定位技术,遥控技术,遥控挖掘装载机,碾压自动化,多台碾压机碾压自动化,机器眼探测裂缝,机器眼安装路面标记,自动封缝机,图控技术,人机对话,遥控管涵安装机,遥控挖掘装载机,桥梁除漆机器人,自动扫雪洒盐机,路面新技术,超级性能路面 玛蹄脂沥青碎石混凝土路面 永久路面,混合料主要特点,严格的材料选择,旋转压密机和体积比设计,沥青性能分级,以天气为基础,PG 64-22,Performance Grade,Average 7-day max pavement design temp,Min pavement design temp,The lower the number, the more resistant to thermal cracking.,PG- 22 - 28 -34,集料特性,基本特性 要求 coarse aggregate angularity (CAA) fine aggregate angularity (FAA) flat, elongated particles (F & E) clay content (SE) 来源特性 选择 toughness soundness deleterious materials polish values,100,0,.075.3 2.36 4.759.512.5 19.0,Percent Passing,Sieve Size (mm) Raised to 0.45 Power,级配,控制点,100,0,.075.3 2.36 4.759.512.5 19.0,Percent Passing,control point,restricted zone,max density line,max size,nom max size,Sieve Size (mm) Raised to 0.45 Power,Marshall Method,19.0 mm,25.0 mm,37.5 mm,9.5 mm,4.75 mm,12.5 mm,AGGREGATE GRADATION Nominal Size: 19.0 mm SMA & 19.0 mm Superpave,Percent Passing,SMA,Superpave,19.0 mm Superpave,Insert I-70,I-70 Ndesign - 96 19.0 mm SMAVTM - 4.3,AGGREGATE GRADATION Nominal Size: 12.5 mm SMA & 12.5 mm Superpave,SMA,Superpave,I-8312.5 mm PG 70-22 Binder,First 12.5 mm SMA,I-68,热压密和紧跟摊铺机!,特性比较,Rut Resistant Durable Skid Resistant Reduced Spray Reduced Hydroplaning Reduced Sound,SuperpaveSMA,Decision Points for using SMA as the Surface Layer, 2000 ESALs per day 55 mph,永久路面路面设计概念,永久路面路面设计概念,抗疲劳沥青基层：通过厚度使拉应变最小,永久路面路面设计概念,抗车辙上面层,集料颗粒摩擦互锁： 轧制和粗颗粒 沥青胶结料： 高温性能和改性 空隙率： 现场4%-6%,永久路面路面设计概念,抗车辙上面层车辙试验验证 现场 加速试验,上开裂,华盛顿州永久路面,州际高速公路90号 47% 没有破坏 27-33年；路面24公分；第一次罩面12年；第二次罩面13年。,厚度比较,性能试验,车辙仪,车辙仪试验结果,路面噪音,FHWA - Noise Abatement Criteria 67 dB(A) “this is not an absolute value or design standard, only a level where noise mitigation must be considered”,The Decibel Scale,Hearing Threshold,Conversation,Pain Threshold,Discomfort,The Decibel Scale,Increasing the decibel level by 10 doubles the noise intensity!,Conversation,Train,Chain Saw,隔音墙,Effective only for those in line-of-sight.,Do not reduce noise at source.,Effectiveness must justify expense. Cases: I-40, Knoxville: $25,000/home I-285, Atlanta: Requirements of 69 dB(A) and 67dB(A), 5dB(A) Nationwide (FHWA, 1998): $1M/mile,隔音墙,Conclusions, “In general, when dense-graded asphalt and PCC pavements are compared, the dense-graded is quieter by 2 to 3 dB(A)”,路面微观构造,67 dB(A),15 m,The Decibel Scale,A reduction of 3 dB(A) is like doubling the distance from the noise.,67 dB(A),30 m,- 3 dB(A) = 64 dB(A),Conclusions: “In general, when dense-graded asphalt and PCC pavements are compared,the dense-graded is quieter by 2 to 3 dB(A)”,A 3dB(A) reduction corresponds to: - doubling the distance - reducing traffic volume by 50% - reducing traffic speed by 25%,Conclusions: “Open-graded asphalt shows the greatest potential for noise reduction for passby noise. Reduction when compared to dense-graded asphalt ranged from 1 to 9 dB(A).”,A 9dB(A) reduction corresponds to: - a reduction in traffic noise by almost 50%!,OGFCsReduce Noise and Improve Visibility,Noise ReductionOpen vs Dense Graded Mixes,Source: NCHRP 284,DOTs indicate a strong need for pavement noise control strategies. Proper selection of pavement surface is the best method to reduce noise from pavement/tire interactions.,What Can Be Done?,OGFC is the quietest surface type. (Wayson, NCHRP Synthesis 268) SMA has also proven to be a quiet surface. (Wisconsin DOT, 1993) Dense graded HMA surfaces are quieter than PCC pavements.(Hibbs and Larson, Report FHWA-SA-96-068, May 1996),Effect of Pavement Surface,Noise Makes News!,Families Near I-275 is lobbying the Michigan DOT for sound abatement. In 1999, MDOT rebuilt I-275 with concrete. Residents contend the project has increase noise levels. Levels have been registered upwards of 90 decibels. Steve Phillips of Berkshire, England-based TRL Limited spoke about Englands 10-year plan to install quieter surfaces on 60% of main trunk roads. The surfaces will be SMA or OGFC.,Summary,Highway noise is important to the public. Small changes in dB level are noticeable. Decrease of 9 dB(A) reduces noise by 50% Decrease of 3 dB(A) is like doubling distance,Summary,Noise walls can work, but: They are expensive. They dont work in all types of terrain. Source of noise is still there. Asphalt pavements can reduce noise at the source by up to 9 dB(A).,Hot Mix Asphalt,Summary,Asphalt pavements for noise reduction in order of effectiveness: OGFC SMA Dense-Graded HMA,PCC,