01033786

Component

http://www.trb.org/Publications/Blurbs/156750.aspx

Historically, compaction of hot-mix asphalt (HMA) pavements was done with steel wheel static rollers until vibratory rollers, introduced in the late 1950s, became the dominant compaction equipment. As difficulties in compacting Superpave mixes were encountered during the 1980s and 1990s, equipment manufacturers made their vibratory rollers bigger, heavier, and with higher vibration frequencies. In some cases, these rollers were so powerful that, during compaction, mix aggregates were fractured, the asphalt mat cracked, and damage to nearby buildings and underground utilities occurred. This latter problem had been evident earlier in European countries due to their narrower city streets and the proximity of many old, historic buildings. Thus oscillation technology was developed in Germany in 1983 and after years of testing and usage in Europe, the oscillatory asphalt roller was introduced in the United States in early 2003. The oscillatory system uses dual, opposed, eccentric weights rotating in the same direction around the roller drum axis to produce a rocking motion. This rocking motion produces horizontal and downward shear forces that achieve greater compaction by "massaging" the HMA--even at lower mix temperatures. Since the drum does not leave the pavement surface or bounce like a conventional vibratory roller drum, the compacted mat surface is smooth and flat and there is no damage to utilities, buildings, or bridges. Numerous tests have shown that oscillatory compaction can achieve higher densities with fewer passes when compared to a vibratory roller. Plus compaction is possible at lower temperatures (down to 150 deg F).

01033774

English

pp 49-53

2006-9

Transportation Research Circular

Print

Figures (3) ; Photos (1)

Density; Hot mix asphalt; Superpave; Temperature; Vibratory compaction

Compaction equipment; Oscillatory compaction; Shear forces

Europe; Germany; United States

Highways; Maintenance and Preservation; Materials; Vehicles and Equipment; I31: Bituminous Binders and Materials; I61: Equipment and Maintenance Methods

TRIS, TRB

Sep 29 2006 10:42AM

• Basics of Longitudinal Joint Compaction
• Compaction of Stiff and Tender Asphalt Concrete Mixes
• Constructing Longitudinal Joints with Lower Voids
• Construction of Durable Longitudinal Joints
• Field Testing of the Zero-Shear Viscosity Method
• Fundamentals of Percent Within Limits and Quality Control–Quality Assurance Compaction Specifications
• Impact of Incentives on In-Place Air Voids
• Measurement of Longitudinal Joint Density in Asphalt Pavements Using Nuclear and Nonnuclear Gauges
• Percent Within Limits Experience on a Design–Build Project
• Prediction of Compaction Temperatures Using Binder Rheology
• State-of-the-Practice for Cold-Weather Compaction of Hot-Mix Asphalt Pavements
• Vibratory Pneumatic Tire Roller
• Vibratory Rollers