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CHAPTER 1
Introduction
Background Because pavementtire noise is controlled primarily by
(1) the tire design and materials and (2) roadway surface tex-
It has long been recognized that the texture of portland ture and material properties, the highway community has been
cement concrete (PCC) pavement surfaces directly influences actively engaged in evaluating the methods used to texture
friction and safety characteristics (American Concrete Insti- pavements. Spurred on by the significantly lower noise of
tute [ACI], 1988). Prior to 1967, most PCC surface textures asphalt concrete (AC) pavement surfaces when compared
were constructed using a burlap drag process. However, at with transversely tined PCC surfaces, particular effort has been
that time, this texturing method did not provide a minimum devoted to developing improved alternatives to the transverse
frictional coefficient of 0.30, as was required by at least one tine texture. Among the earlier alternatives were (1) the longi-
state--California (Neal, 1985). Consequently, other textur- tudinal tine that California specified starting in 1978 in spite
ing methods were developed to improve frictional/safety of the requirement of FHWA guidelines for transverse tining
characteristics, the most common of which is transverse tining (Neal et al., 1978; Hibbs & Larson, 1996); (2) the random
(grooving the PCC surface perpendicular to the traffic direction (i.e., variable) transverse tine that was found to reduce or
prior to curing). The uniform narrow grooves provide water eliminate the "whine" associated with uniform transverse
drainage and increase the macro-texture of the surface, result- tining; and (3) the random (i.e., variable) skewed transverse
ing in good wet-weather pavementtire friction and report- tine that was shown to eliminate whine and reduce overall
edly a good safety record. noise (Kuemmel et al., 2000).
As the volume of urban traffic increased steadily, vehicle Other methods of noise reduction for PCC pavements have
noise emission became a concern (ACI, 1988). In 1973, the been evaluated internationally and more recently in the United
Federal Highway Administration issued Policy and Procedure States. These include longitudinal diamond grinding, longitu-
Memorandum 90-2, Noise Standards and Procedures that estab- dinal grooving, exposed aggregate concrete (EAC), porous
lished noise criteria for federally funded highway projects PCC, shot-abraded PCC (e.g., Skidabrader), and ultra-thin
(FHWA, 1973). From this time through 2004, over 2,205 mi proprietary surfacings (e.g., NovaChip® and Italgrip® System).
(3,550 km) of noise barriers or combination berms and barri- Various strengths and weakness have been reported for all of the
ers were built at a cost of over $2.7 billion (FHWA, 2006). The methods with regard to initial and long-term noise, friction,
criteria have since been updated and are currently outlined in and other surface characteristics, as well as constructability and
the Code of Federal Regulation (CFR) Title 23, Part 772, Proce- economics. Identifying optimal textures for various highway
dures for Abatement of Highway Traffic Noise and Construction conditions and environments has been the goal in many of the
Noise (U.S. Federal Government, 2008). past and ongoing investigations, and it is the goal in this study.
While significant reductions in vehicle engine and drive-
train noises were achieved in recent years, the noise associated
Description of the Problem
with pavementtire interaction has not been significantly
reduced (Sandberg and Ejsmont, 2002). Public concern (espe- Tining generally is performed to enhance pavement-surface
cially in urban areas) over the issue of high traffic noise and frictional characteristics and reduce potential for hydroplan-
the substantial costs associated with noise emissions barriers ing, skidding, and wet-weather crashes. However, there is a
have led to renewed interest in pavements that exhibit low- concern that the use of tining has evolved without adequate
noise properties under traffic. consideration of the effects on noise generation, long-term
