Pavement Preservation Journal - Winter 2014 - (Page 25)

Open Graded Warm Mix Boosts County Dirt Roads By Ellie Payne of the South Carolina Low Country, most recently for Joseph White Road. IMAge CReDIT: MWV eVOTHeRM CUTTING COSTS IN LAB The South Carolina DOT's OGFC mix - designed to funnel water off of interstate highways - is the standard in the state for pervious paving, but was too expensive for the county. The permeable pavement works great for highways and interstates to prevent hydroplaning and overspray, but was a bit excessive for the dirt byways of southeastern South Carolina. Instead, the state OGFC mix was adapted to include 5.5 percent PG IMAge CReDIT: MWV eVOTHeRM Low-volume, sandy, soil-based roads of Charleston County in the South Carolina Low Country need stronger but inexpensive surfacing Thin open graded friction course incorporating warm mix additive surfaced sandy, soil-based road IMAge CReDIT: MWV eVOTHeRM C harleston County, S.C., has a relatively high number of low-volume, unpaved earth roads within its jurisdiction. In fact, in the county, 380 rural dirt roads currently demand regular maintenance, which is taxing the budget beyond its limits. "We need to pave these roads because the regular maintenance is very expensive," said Matthew Fountain, engineering manager of Charleston County Public Works. "Traditional paving methods are not economically feasible. New regulations make the permitting process cumbersome and working the drainage system around protected trees and driveways can be bothersome for residents, not to mention the expense. We need something that is economical, constructible, and sustainable." To improve access and safety for residents, the county has turned to pervious paving as a solution. Pervious, or porous, paving is a technique that features open graded friction course (OGFC) asphalt with 20 percent air voids as an alternative to the dense asphalt used on most roads, which may have air voids in the 4 to 5 percent range. The mix quickly drains water from the pavement, reducing hydroplaning and water spray, and suppresses pavement noise at the pavement/tire interface. The technology has been around for decades but developing the right mix for the right price can be a challenge to a road agency with limited funds. MWV Specialty Chemicals, located in Charleston County, and Sanders Brothers Construction, worked with Charleston County to develop a unique, cost-effective warm mix asphalt using Evotherm warm mix additive, a mix designed specifically for the low-volume, sandy, soil-based roads Comparison of aggregate gradation for interstate and rural OGFC in South Carolina Winter 2014 pavement preservation journal 25

Table of Contents for the Digital Edition of Pavement Preservation Journal - Winter 2014

President's Message
NCAT, MnROAD Partnership - New Era in Preservation Study
R26 Workshop: Breakout for High Volume Highway Preservation
Penetrating Emulsion, Double Chip Seal Saves Unpaved Road
Open Graded Warm Mix Boosts County Dirt Roads
You’ll Benefit from PPRS Paris 2015
CIR, Thin Seal Work Wins Norjohn Ontario Green Award
Digging PCC ‘Buried Treasure’ Beneath Asphalt Overlays
Polymer-Based Materials for Unpaved Road Maintenance
Index of Advertisers

Pavement Preservation Journal - Winter 2014