• Chapter 9

STRATEGIES AND NETWORK NEEDS

Session Objective

The objectives of this session are to enable participants to

• Relate the results of condition assessment to the most appropriate

maintenance and rehabilitation strategy for a road section.

• Identify overall network needs to arrive at funding requirements.

Determining Strategies

• Once the pavement condition information is collected it must be analyzed

to determine the maintenance and rehabilitation needs. This analysis must be

made using certain standards, along with sound engineering judgment. The

analysis should look at the measured condition of each section and determine

the cause of the observed distress and how it can best be corrected.

A basic concept of pavement management is that maintenance resources

should be spent on only those pavements that are in good enough condition to

warrant such expenditures. It should be pointed out that a pavement will

generally perform well for a number of years. Once the deterioration process

begins, however, the pavement fails very quickly. Deficiencies which were

originally in the pavement surface can quickly snowball and become structural

deficiencies. When this occurs, the cost of pavement rehabilitation increases

dramatically in a relatively short period of time.

Given the present condition of a pavement, there is a maintenance and

repair strategy that is most appropriate. "Strategy" refers to an overall

approach to maintenance and repair actions. It is helpful to avoid confusing

(1) how an activity is funded with (2) this concept of strategy. It really

doesn't matter if a surface treatment, for example, is applied with in-house

forces or by contract. As far as long-term performance of the pavement is

concerned, it only matters that the proper preventive maintenance activity was

• applied at the right time .

9-1

There are five general strategies that can be considered for paved

surfaces:

Routine Maintenance - For roads in reasonably good condition, routine

maintenance is generally the most cost-effective use of funds. If at all

possible, all routine maintenance needs should be funded each year. Routine

maintenance usually includes local patching, crack sealing, and other

relatively low-cost actions. Distresses such as isolated medium or high

severity bumps or potholes that may have a considerable negative impact on the

performance of a section are usually corrected first.

Preventive Maintenance - This strategy is a more expensive activity

designed to arrest deterioration before it becomes a serious problem. Surface

seals are excellent examples of preventive maintenance. A common source of

poor performance of seals is inadequate repair of existing distress before

sealing, so extensive repair work may also be included in preventive

maintenance. Repair and seal needs will probably have to be programmed over

several years in order of priority because of the expense. Routine

maintenance should be performed on those sections that are not programmed for

the current budget year. • Deferred Action - The road sections which fall into this category receive

minimum funds for the current budget year. These sections are beyond the

point where preventive maintenance will be effective but have not yet

deteriorated to the point of needing rehabilitation. Selecting this strategy

is deferring action, so an agency must be prepared to fund rehabilitation or

reconstruction when it becomes necessary. This strategy is normally not

appropriate for aggregate surfaced roads.

Rehabilitation - Rehabilitation usually includes overlays or extensive

recycling. Funding for completion of these major projects may depend upon

federal or other outside sources. The established priorities should be

followed if possible, although managers should realize that priorities may

change for a variety of reasons. For example, estimates for a particular job

may exceed available funds, insurmountable administrative restrictions on

funds may exist, or very valid political reasons to change priorities may • 9-2

•

•

•

occur. Sections that fall into this strategy category that are not programmed

for the current budget year should fall into the deferred action strategy.

Reconstruction - The comments on rehabilitation projects also apply to

reconstruction projects. The main difference is in the costs that might be

expected. Reconstruction would involve complete removal and replacement of a

failed pavement and might also involve features other than just pavement such

as widening, realignment, traffic control devices, safety hardware, and major

drainage work. Lead times of five to ten years might be required because of

the significant nature of required investments and the time necessary to

develop plans, acquire right-of-way, and other funding.

Typical Actions - Exhibits 9-1 through 9-4 list typical actions that

might be performed within each strategy.

The proper maintenance and repair strategies are best selected using a

life-cycle cost analysis. This process can be time consuming if attempted for

every decision for every pavement section. If a detailed economic analysis is

not used, the most appropriate strategy can be selected using a logic scheme

as suggested in Exhibits 9-5 and 9-6. Such a scheme, of course, can be

refined with a life-cycle analysis using average costs for typical activities,

then using the resulting decision criteria as the standard for all sections.

If such an approach is taken, different criteria for each pavement type can be

selected.

It should be noted that there is considerable overlap of possible

strategies on the PCI performance curve. In the example shown in Exhibit 9-5,

there are two or three possible strategies for any PCI value from 25 to 15.

This is a very realistic approach because the deterioration of pavements is a

gradual process. A change in just a few PCI points will not usually make one

strategy preferable over another.

Within certain ranges of condition, one must look at the factors that

went into the overall condition rating. Predominately surface distress such

as weathering, ravelling, or bleeding would indicate a need for preventive

maintenance over other strategies. On the other hand, if most of the

condition rating is a result of structural distress such as alligator

cracking, potholes, or failed patches, then it may be best not to expend

preventive maintenance funds and plan a rehabilitation effort. Roughness can

also help determine strategy decisions.

9-3

Exhibit 9-l' TYPICAL ACTIONS

AGGREGATE SURFACE • Strategy

A. Routine Maintenance

B. Preventive Maintenance

D. Rehabilitation

E. Reconstruction

Recommended Actions

• Blading

• Local repairs

• Pothole filling

• Ditch cleaning

• Dust control

• Strategy A actions as necessary

• Spot aggregate addition

• Scarifying and recompaction

• Strategy A and B actions as necessary

• Stabilization • A structural addition of aggregate (2

inches or more)

• Strategy D actions as necessary

• Removal and replacement of the entire

pavement structure

• Paving with a surface treatment,

asphaltic concrete or portland ceme~t

conc rete.

• Geometric, safety, and traffic

improvements as necessary

•

• 9-4

• Exhibit 9-2

TYPICAL ACTIONS

FLEXIBLE PAVEMENTS

Strategy

A. Routine Maintenance

B. Preventive Maintenance

C. Deferred Action

• D. Rehabilitation

E. Reconstruction

Recommended Actions

• Crack sealing

• Skin patching

• Local repairs

• Strategy C actions as necessary

• Strategy A and C actions as necessary

• Surface seals

• Thin overlays

• Patching of high severity potholes,

shoving, corrugations and rutting

• Strategy A, B, and C actions as

necessa ry

• Removal of a portion of the surface if

necessa ry

• Structural overlay

• Strategy D actions as necessary

• Removal and replacement of the entire

pavement structure

• Geometric, safety and traffic improvements as necessary

9-5

Exhibit 9-3

TYPICAL ACTIONS

RIGID PAVE'MENTS • Strategy Recommended Actions

A. Routine Maintenance • Crack sealing

Local repa irs of low to medium severity• faulting, blow-ups and divided slabs

• Strategy C actions as necessary

B. Preventive Maintenance • Strategy A actions necessary

Limited slab replacement• • Clean and seal joints

• Slab stabilization

• Strategy C actions as necessary

C. Deferred Action • High severity blow-up repa i r

• High severity divided slab repair •D. Rehabilitation • Strategy A, B, and C actions as necessary

• Up to 50 percent slab replacement

• Grinding or milling to restore rideabi 1ity

• Structural overlay

E. Reconstruction • Strategy D actions as necessary

• Greater than 50 percent slab replacement

• Removal and replacement of entire

pavement structure

• Geometric, safety, and traffic

improvements as necessary

9-6

• Exhi bit 9-4

TYPICAL ACTIONS

COMPOSITE PAVEMENTS

•

Strategy

A. Routine Maintenance

B. Preventive Maintenance

C. Deferred Action

D. Rehabilitatlon

E. Reconstruction

Recommended Actions

• Crack sealing

• Skin patching

• Local repairs • Strategy C actions as necessary

• Strategy A and C actlons as necessary

• Surface seals

• Thin overlays

• Slab stabilization

• Patching and repairs of high severity

blow-ups, and bond loss

• Strategy A, B, and C actions as

necessary

• Removal of overlay portion

• Joint repairs

• Structural overlay

• Strategy 0 actions as necessary

• Grinding or milling PCCP to restore

rideabi 1ity

• Removal and replacement of the entire pavement structure

• 9-7

---------------------------------

--------------------------------

Matching Condition Assessment and Strategy

The overall rating, actual distresses and their causes, and performance •of the surface over time should be analyzed to determine the most appropriate

strategy. A strategy should be thought of as an overall approach at this

point rather than specific decisions about where to patch or how many inches

of overlay to apply.

EXHIBIT 9-5 MAINTENANCE AND REHABILITATION STRATEGIES

A. ROUTINE MAINTENANCE

B. PREVENTIVE MAINTENANCE

100 r-~-~-~-~-~-~-~-~-~-~-~-~-~--.......... 90

80 D. REHABILITATION

--------------------------------------

1-+-1f----'~ C. DEFER ACTION •

70

E. RECONSTRUCTION 60 o

Q.

50

40

30

20

10

YEARS

• 9-8

• . vI r .

JAIi'v r4'" r ~ l Exhibit 9-6 1~~~~ MAINTENANCE AND REHABILITATIONk

rr V\ STRATEGY SELECTION

•

PC I Other Considerations Strategy

76-95 None A

61-75 Normal or Small Amount

of Surface Distress

Mostly Surface Distress

A

B

51-60 Mostly Surface Distress

Distress Evenly Balanced

Mostly Structural Distress

very Rough (PSI < 2.0)

or

B

C

o

41-50 Relatively Smooth

Rough (PSI ~ 2.5)

(PSI ~ 2.5) C

o

26-40 Relatively Smooth

Very Rough (PSI ~

to Rough

2.0)

(PSI~ 2.0) o E

0-25 None E

Strategy Keys:

A ­

B ­

C ­

D ­

E ­

Routine Maintenance

Preventive Maintenance

Deferred Action

Rehabilitation

Reconstruction

• 9-9

Elements of Fiscal Policy

Many elements of society have encountered severe problems in meeting • financial obligations. Local governments are no exception. Long-standing

financing practices are often not adequate to meet today's needs and this is

particularly true in regard to local roads. In developing roadway programs,

however, it is helpful to remember some basic principles of roadway finance

which have stood the test of time. A sound roadway finance policy should:

• Assess roadway needs clearly

• Provide budget amounts that are adequate and affordable

• Involve the public in defining needs, funding levels, and taxes

• Provide funding levels that are predictable

• Maintain or establish an equitable tax structure

• Be simple to administer and easy to understand • Estimates of expenditures are critical to the development of policy and

program contents for the current and future fiscal years. Crucial to that

development is a projection of current trends to establish future needs. It

is essential that the level and quantity of work output for a given fiscal

year be developed to provide a solid financial planning base. Detailed work

plans will serve to place long-term plan components within a budgeting year

framework.

Capital investments must be programmed for implementation. It is

increasingly important for a capital program to consist of a systematically

prioritized group of projects. This helps insure that the scarce dollars are

used effectively in meeting public needs.

• 9-10

• Goals and Objectives

The logical sequence in establishing a plan for roadway maintenance and

capital improvement investments is to first decide upon long-range goals and i

objectives, develop a program to reach those objectives (usually for 5-years),

and finally begin implementation of that program with the upcoming annual !

budget.

Without the first step of clearly deciding where the local government

wi~hes to be in 10 or 20 years, annual road maintenance and capital

improvement programs are unlikely to be particularly beneficial in the long

ru~. The establishment of goals and objectives is properly a political

pr~cess that should include the full participation of the public. Public

input not only reveals specific needs and areas of concern but will also help I ensure support for the adopted program.

Many communities have master plans that have established general

lorlg-range goals and objectives. Specific transportation plans may also

ex'st, along with land-use plans. Goals and objectives for road surfaces

sh~uld be established within the overall frame-work of these more general

pl~ns. The integration of these two concerns has at least two positive side

ef~ects:•I

• Those concerned with the condition and maintenance of road surfaces

will become better acquainted with overall transportation needs and

plans and can better anticipate impacts on their operations.

• Planners will become more sensitive to the impacts of large capital

improvement programs on operations and maintenance.

Road surface goals and objectives can take many forms. Some examples are:

• Pave all roads with ADT's in excess of 100 vpd.

• Within 5-years raise the average PCI of the network to the following

levels:

• - Arterials - 70

Collectors - 65

Local Access - 60

9-11

• Lengthen the period between surface treatments from five years to

seven years, without lowering the level of condition. • • Lower the portion of the surface maintenance budget for unplanned,

emergency maintenance to 20 percent.

Clearly stated, achievable, long-range goals and objectives help to keep

programs and budgets in focus, for all members of an organization, as well as

managers. Goals and objectives that have been adopted by an elected board

also make it easier to justify funding programs that have been developed to

achieve those goals and objectives.

Determining Network Needs

There are three general approaches to determining overall pavement needs,

in terms of dollars. Regardless of the approach taken it is important to

associate costs to goals and objectives. If this can be done with some degree

of creditability managers will find program and budget approval much easier.

Each of the three approaches are discussed below, from the most simple to the

most complete: • Historical Trends - In the absence of inventory and condition data, local

governments can review expenditures for various strategies over a period of

time (say five to ten years) and relate these expenditures against a

subjective evaluation of the condition of the road surfaces. This is the

procedure that local governments must use in the absence of a more formal

procedure. Although this procedure may appear rather crude it can be refined

and made very useful for very small networks. The key to successful use of

this procedure is to document the condition of the network so performance can

be tracked over time. This allows for an evaluation of the effectiveness of

funding levels so the projections and needs can be determined.

Frequency of Activity - This procedure uses the average life of certain

activities, average costs, and the network inventory to arrive at total network needs in terms of average annual investments. Perhaps the best way to

describe this process is a simple example. A rural county has 48 miles of • 9-12

bituminous surface treated (SST) roads. If the average cost of the SST is

• $7l200 per mile of 2-lane road and SST lasts an average of six years, then the

avkrage annual network need would be: I

(48)(7,200) = $57,600

6

Si~ilar evaluations would be needed for other surface types and treatments.

I Systematic Approach - The frequency method is very helpful in arriving at

aVfrage investment requirements but does not take into account actual

COpdition nor needed changes in strategies. In fact, some of the roads in the

abfve example may be performing very well and will need a treatment only every

ei~ht years. Others may be failing after two years and infact should be

reyonstructed with a more substantial pavement structure.

• The most complete way to arrive at total network needs is to assess

co6dition and assign strategies to each section, as discussed in Chapters 7,

8,l and 9, then apply average unit costs to each strategy and area. The result

Of!this process will be the total current network needs, using the most

ap~ropriate strategies to fit current conditions.

I A systematic approach can use portions of the two procedures discussed

earlier to help arrive at network needs and long-range goals and objectives.

Foh instance, if records are kept of levels of investments along with average

patement condition measurements as a result of distress surveys, then average

costs to raise the network condition can be developed. Also, expected

frJquencies of activities can be used along with the currently assignedI Istrategy to help arrive at long-range needs.

At its most sophisticated, a systematic approach to network needs might

arrive at an average network condition (say a PCI of 58) and a total current I

neJd of $200,000 to raise the PCI to 80. Assuming that the total needs cannot

be funded immediately, it is possible to arrive at a target average condition,

th~ years it will take to arrive at that condition, and the average annual I

in~estment needed to accomplish that objective. Using our example, a I

• long-range goal might be to bring the network condition up to 75 within four

ye~rs with an average annual investment of $65,000. This type of analysis can

be idone subjectively using the best information available along with plenty of i

engineering judgment, or it can be done quantitatively (which normally I

reduires a computer).

9-13

Bibliography

• Evaluation of Pavement Maintenance Strategies, NCHRP Synthesis 11, •Transportation Research Board, September 1981.

•

• 9-14