2018-048 Milling Contract ISRDate: May 4, 2018 Report No. 2018-048
INFORMAL STAFF REPORT
TO MAYOR AND CITY COUNCIL
SUBJECT:
To provide background information on the City’s street milling efforts in advance of a milling
maintenance contract planned for City Council consideration on May 22, 2018.
BACKGROUND:
Milling is an integral part of the construction cycle of any road. It is the controlled removal of
asphalt or concrete pavement to a desired depth. Milling can solve road deterioration problems
like ruts and unstable asphalt, poor skid resistance, bonding quality, poor pavement profile and
over-asphalted streets. Milling can be used to remove maintenance material and surface flaws to
prepare the surface for an overlay. It can also roughen or texture concrete pavement to restore or
improve friction to the surface that has become smooth over time. The City of Denton maintains a
total of 1331 lane miles (949 are made of asphalt and 382 of concrete).
DISCUSSION:
The milling process is used in both the reconstruction of road CIP projects and preventive
maintenance programs here in Denton. During a reconstruction project, the entire road surface will
be milled off in one pass leaving the subgrade below. The millings can then be recycled back into
the new road that will be reconstructed.
With the preventative maintenance program, only the top few inches of the roadway is milled off.
This allows crews to replace (overlay) only the worn surface with a new asphalt surface. This
increases the Pavement Condition Index and allows the road for it to reach its full life span of 30+
years. If the road is left untreated, the normal life expectancy is roughly 12 years.
The City of Denton uses a 100-point scale for their Pavement Condition Index (PCI). The
Pavement Condition Index combines surface distress (such as rutting, cracking, potholes, punch
outs, and patches) and ride quality into a single index that ranges from 1 (worst condition) to 100
(best condition). The City of Denton’s goal is to raise the average Pavement Condition Index (PCI)
from an average of 65 to a 70 by 2025.
The following steps are used on an annual basis to determine which streets receive the milling
process:
1. Streets are selected for Mill and Overlay (maintenance) by first using the Pavement
Condition Index to identify the streets that are in the 75 - 60 range.
2. Streets scored within the 75-60 range are then visually inspected by City crews to confirm
the scoring.
3. The confirmed list is compared to projects planned in CIP, Water, Wastewater, and
Drainage. This determines if any of the roads have other planned maintenance and
replacement of infrastructure.
Date: May 4, 2018 Report No. 2018-048
4. Roads that are not requiring maintenance or that are already planned for other infrastructure
work are removed from consideration and the remaining streets is the final list.
To maintain productivity levels in the street preventative maintenance program, the City’s milling
program is conducted by City crews and by an outside contractor. City crews are able to handle
smaller milling jobs with City-owned equipment and larger milling work is provided by a
contractor. Staff believes this is a good complement of resources as it allow more roads to be
maintained simultaneously.
On May 22, 2018, staff plans to bring forward a one year (with three (3) additional one (1) year
extensions) milling maintenance contract in an amount not to exceed $2,175,166. Currently the
City of Denton Streets Department has identified 27 streets, totaling 18 lane miles of roadway,
which will be completed for year one of this contract.
CONCLUSION:
In summary, it is the opinion of staff that the milling of streets is a beneficial component of the
City’s street maintenance program.
The City Council will be considering a one year (with three (3) additional one (1) year extensions)
milling maintenance contract at its May 22, 2018 meeting for an amount not to exceed $2,175,166.
If the City Council approves the contract it allows the City of Denton Streets Department to
proactively maintain the City’s streets and work towards raising our overall Pavement Condition
Index to better serve our citizens.
ATTACHMENT(S):
Pavement Condition Index Graph
Anticipated year one streets mill and overlay list
STAFF CONTACT:
Daniel Kremer
Deputy Director of Operations
Streets and Storm Water Division
Capital Projects Department
(940) 349-7193
Daniel.Kremer@cityofdenton.com
Date: May 4, 2018 Report No. 2018-048
Date: May 4, 2018 Report No. 2018-048
Street From To Lane Miles
Linden Malone Ponder 1.23
Panhandle Carroll Bolivar 0.30
Gober Scripture Panhandle 0.61
Market Loop 288 Blake 0.47
Linden
Bonnie
Brae Thomas 0.50
Stuart Windsor Kings Row 1.30
Emery Alice Coit 0.33
Westwood Oakwood Willowwood 0.26
Hercules Nicosia Fallmeadow 0.86
Ave C Oak Hickory 0.28
Highland Carroll IOOF 0.41
Nottingham 380 Windsor 3.96
Rockwood Hanover Mistywood 0.87
Texas Bell Oakland 0.44
Oakwood McCormick Dead end east 0.53
Mercedes Oakwood Willowwood 0.26
Coit Congress Panhandle 0.42
Crescent Malone Aileen 0.59
Mistywood Old North Dead end east 0.93
Bryan Scripture Oak 0.56
W. Congress Bryan Malone 0.36
Sun Valley Stuart Dead end
west 0.53
Oakridge Edgewood Crestoak 0.28
Valley View Kings Row Sun Valley 0.65
Crestwood Glenwood Kaywood 0.50
Crestoak Live Oak Oakridge 0.23
Crestwood
PL Live Oak Edgewood 0.52
Total 18.19