Pavement Preservation Preventive Maintenance Introduction to Pavement Preservation Preventive Maintenance This module provides background information and introduces the concepts of pavement preventive maintenance. It is included to help all participants approach pavement preventive maintenance from a similar viewpoint.

Learning Outcomes Explain the concept of Pavement Preservation and preventive maintenance treatments Discuss the importance of treatment timing List the benefits of a pavement preservation program Describe a good candidate pavement for preventive maintenance Build slide. Introduce these learning outcomes by stating “At the end of this course, you will be able to….”

Pavement Preservation Concept The basic philosophy behind pavement preventive maintenance is keeping good roads in good conditions. This definition covers all pavement activities. The real challenge is identifying the right treatment, the right pavement, and the right time. It’s more of a challenge because we are trying to do this within a framework or to meet a set of objectives. Point out that federal dollars can be used for preventive maintenance. Keeping good roads in good condition! Upgrading Fair roads to good condition!!

Coordinated Pavement Preservation/Rehabilitation Programs

Pavement Preservation Pavement Preservation is a cost-effective set of practices that extend pavement life and improve safety and motorist satisfaction while saving public tax dollars. Pavement Preservation is "a program employing a network level, long-term strategy that enhances pavement performance by using an integrated, cost-effective set of practices that extend pavement life, improve safety and meet motorist expectations." Without Adding Additional Pavement Structure

Pavement Preservation Pavement Preservation is "a planned strategy of cost-effective treatments applied to structurally sound pavements that preserves the system, retards future deterioration, and maintains or improves the functional condition of the system (without significantly increasing the structural capacity).

How do preventive treatments differ from routine/reactive treatments? Similar treatments… different TIMING! Q: How do preventive maintenance treatments differ from maintenance treatments used in a reactive or routine manner? A: Although some maintenance treatments such as pothole patching are “stop-gap” maintenance activities, they are not ever used in a “preventive” manner. Most of the preventive maintenance treatments are the same maintenance treatments used in a routine/reactive manner, it is just the timing of the treatment that differs. For example, when a chip seal is applied when the surface condition is poor, it is considered a “reactive” (or maybe a routine) treatment. However, if applied when the pavement condition is relatively good, the treatment is considered a “preventive” application. Planned Age of pavement or surface Condition of pavement

Routine Maintenance Reactive in nature Fixing a defect once it occurs Main purpose is to keep traffic moving Performed in harsh conditions Poor performance and greatest ire from travelling public

Pavement Preservation Applying the Right treatment to the Right pavement at the Right time. Preserves the system Retards future deterioration Maintains or improves functional condition of the system. (without increasing structural capacity).

Pavement Rehabilitation Resurfacing, restoration, and rehabilitation work undertaken to restore serviceability and to extend the service life of an existing facility. This may include recycling of existing pavement, placement of additional surface materials or other work necessary to return an existing pavement, including shoulders, to a condition of structural or functional adequacy.

Pavement Reconstruction Construction of the equivalent of a new pavement structure Complete or partial removal and replacement of the existing pavement section including new and/or recycled materials.

Pavement Condition vs. Time Do Nothing Pavement Preservation Condition Pavement Rehabilitation Pavement Reconstruction Time

Proactive Approach Applies low-cost preventive treatments 5 to 7 year of remaining life Timing is critical Good to Fair Condition Minimal or NO structural damage Once structural damage has occurred then preventive maintenance treatments are of little value. Applying PP treatments to unsuitable pavements has been its biggest barrier to gaining widespread acceptance for the PP concept. A true preservation approach involves the application of a series of successful low cost preventive maintenance treatments that individually will last for several years. The key is to apply the right treatment at the right time. This means applying it to the candidate pavement when it is still in good condition and there is no structural damage. One structural damage has occurred then preventive maintenance treatments are of little value. Applying PM treatments to unsuitable pavements has been its biggest barrier to gaining widespread acceptance for the PM concept.

Past Failures Individual Vendor applying the Wrong Treatment on the Wrong Pavement at the Wrong Time. “Snake Oil” Salesmen – Cure All Premature Failures Many agencies respond to construction failures by issuing moratoriums on the future use of the treatment. Often these construction failures are the result of failing to: Select the right project. Use the right materials. Follow the correct construction procedures. Perform the necessary quality control checks. The goal of the course is to help both contractors and agencies do a better job of constructing preventive maintenance treatments so that we can get in, fix it once, fix it right, get out, and stay out.

... or learning from failure Failing to Learn Over-applied band-aid crack sealant leads to moratorium in New York Cracked windshield claims lead to bans (many agencies) Claims in Michigan lead to restrictions on double chip seals and microsurfacing Many agencies respond to construction failures by issuing moratoriums on the future use of the treatment. Often these construction failures are the result of failing to: Select the right project. Use the right materials. Follow the correct construction procedures. Perform the necessary quality control checks. The goal of the course is to help both contractors and agencies do a better job of constructing preventive maintenance treatments so that we can get in, fix it once, fix it right, get out, and stay out. ... or learning from failure

Pothole Advantages? Slows down traffic!

Benefits of Pavement Preservation?

Importance of Treatment Timing Pavement Preservation Rehabilitation Pavement Condition Reactive Maintenance Build slide. Use this slide to more specifically demonstrate the consequences of waiting to apply a particular maintenance treatment. Introduce the chart by showing a standard “do-nothing” performance curve. Next, show the “old” method of applying “reactive” maintenance later in the pavement’s life as a stop-gap maintenance method. Note the relatively small increase in condition and steep slope of the reactive maintenance performance curve as the application buys some, but generally little, time. Next, show how conducting rehabilitation later in life instead of reactive maintenance gives you more initial condition improvement and life extension, but it also comes with a much larger price tag. Finally, show the concept of preventive maintenance where the “same” treatment (as the reactive maintenance) is applied when the pavement is much younger and in much better condition. Applying the same treatments when the condition is good can buy more life, and better condition, for the same money. Actual preventive maintenance programs must be “local.” That is, agencies have to learn what these curves look like for their own pavements. Time or Traffic

Preserving the Investment Keep water out! Reduce debris infiltration into joints or cracks Slow aging effects of bituminous pavements Minimize dynamic loads The rougher the pavement surface, the higher the impact of dynamic vehicle loadings Q: How, specifically, does preventive maintenance work to preserve the investment? A: This build slide shows some of the specific influences of preventive maintenance that benefit pavement performance. Others? Reducing water infiltration helps protect the underlying layers from being softened or washed away and reduces the effects of freezing and thawing in colder climates. Keeping incompressibles out of joints and cracks greatly reduces the potential for HMA and PCC crack deterioration, PCC joint spalling, and blow-ups in PCC pavements. Surface treatments can be used to slow asphalt aging/hardening on HMA pavements. The rougher the pavement surface, the higher the impact of dynamic vehicle loadings. Explain dynamic loadings if necessary.

Maintaining High Level of Service Maintain good rideability Maintain good surface friction Minimize potentially dangerous surface characteristics Recall that LOS addresses “functional” performance. Q: Based on all of the types of preventive maintenance techniques that have been presented in this module, what does preventive maintenance specifically do to “maintain an acceptable level of service for the pavement surface?” A: Use this build slide to show some of the typical answers. Others? Many of the preventive maintenance activities are applied to “maintain good rideability.” Pavement smoothness is probably the pavement characteristic most noticed by the traveling public. Other preventive maintenance activities are applied specifically to improve surface friction. Maintaining good surface friction improves roadway safety (mainly by reducing hydroplaning potential, and therefore, wet-weather accidents). Preventive maintenance treatments are often effective at “correcting” potentially dangerous surface characteristics such as rutting that can lead to hydroplaning, or edge drop off.

Impact on Distress Prevent or slow some distresses from occurring Correct minor surface deterioration The benefits of preventive maintenance can be assessed by monitoring its immediate impact on distress, as well as the treatment’s performance over time. Specifically, preventive maintenance can: Prevent or slow many distresses from occurring (e.g., blow-ups on PCC pavements; rutting associated with subgrade softening on HMA pavements). Correct some minor surface distress when applied (e.g., surface friction restoration, microsurfacing to fill ruts). Make the point that preventive maintenance does not address all types and severities of surface distress.

HMA Problems Reduced/Slowed with Pavement Preservation Oxidation/raveling Block cracking Edge cracking Crack deterioration Roughness Potholes Q: What HMA distresses can be reduced/or slowed with preventive maintenance? A: Hitting any key will cause the list of prevented/slowed problems to fly in. This list of distresses are slowed or prevented because of preventive maintenance treatments’ ability to seal a pavement. Specifically, sealing the pavement protects the surface from oxidizing/hardening and keeps water out of the pavement structure.

HMA Problems Corrected with Pavement Preservation Minor rutting Raveling Bleeding/flushing Surface friction loss Roughness Q: What HMA distresses can be corrected with preventive maintenance? A: Hitting any key will cause the list of minor distresses effectively corrected with different preventive maintenance problems to appear. Note that these are all “functional” problems. Point out that minor rutting is correctable under preventive maintenance only if its development is not due to subgrade softening.

PCC Problems Reduced/Slowed with Pavement Preservation Loss of fines (pumping) Corner breaks Joint faulting Joint spalling Crack deterioration Roughness Blow-ups Q: What PCC distresses can be reduced/or slowed with preventive maintenance? A: Hitting any key will cause the list of prevented/slowed problems to fly in. These distresses are slowed or prevented because of preventive maintenance treatments’ ability to keep water and incompressibles out of cracks and joints.

PCC Problems Corrected with Pavement Preservation Joint seal damage Map cracking and scaling Surface friction loss Roughness Q: What PCC distresses can be corrected with preventive maintenance?” A: Hitting any key will bring in the list of minor distresses effectively corrected with preventive maintenance. Again, note that these are not “structural” problems.

Evaluating Pavements for Pavement Preservation Condition Friction Roughness Ability to carry loads Although it is not ideal, a pavement evaluation currently provides the most direct information about whether or not preventive maintenance is an appropriate strategy. Information that is useful to process includes: The types of visible distresses. The surface friction characteristics. The roughness (or smoothness) of the pavement. The structural capacity of the pavement. Note: Stress that sub-surface distress can be present without visible signs on the surface. Therefore, when you start seeing visible signs of distress, it may sometimes be too late. There are many different types of condition surveys, including both manual and automated surveys. All begin with a standard way to define the type, severity, and extent of distress. Ask the class participants the following questions to better identify their current practices: Q: Who does surveys for project selection? Q: What distresses suggest the need for preventive maintenance? Q: What distresses suggest it’s too late? Q: Is a survey performed immediately prior to the project?

Good Candidate Pavements for Pavement Preservation No structural failures Minimal distress (extent and severity) Relatively young in age Minor functional problems Few historical problems with similar projects Q: What are the characteristics of pavements that you would consider “good” candidates for preventive maintenance? A: Pavement characteristics that describe good candidates for preventive maintenance are shown on this slide. Q: What do we need to know to make this decision? (Ask the audience for some help in determining a list of items. Some examples of pavement characteristics are shown on this slide. Possibly make a list on the white board). After a list of pavement characteristics has been determined, try and get the audience to interpret these characteristics and really focus on what we need to know to determine if a pavement is a good candidate. Two types of information are really needed to make an educated decision about whether or not a given project is a good candidate for preventive maintenance: We need to estimate the current “condition” of the pavement (the next slide discusses what we mean by “condition”). We need to estimate the expected “future performance” of the pavement. Therefore, we are trying to determine where the pavement is on its pavement performance curve.

When is it too late for Pavement Preservation? HMA Problems PCC Problems Potholes Severely deteriorated cracks Delamination Unstable rutting Blow-ups Corner breaks Severely deteriorated cracks One thing that you can assess from a distress survey is if it is too late to consider “preventive” maintenance. This slide summarizes problems that indicate that the window for preventive maintenance has closed. See if the class can identify that signs of structural deterioration are indicators that preventive maintenance is not appropriate. Material problems are not broken out here, but if there is a known problem (especially in PCC) it is unlikely to be a candidate. Also, while some of these may begin as low severity environmental problems (e.g., potholes), by the time the distress is severe or widespread, preventive maintenance may not be appropriate. Q: What types of distresses on an HMA pavement make it an inappropriate candidate for preventive maintenance? A: Hit any key to have the list of HMA problems appear. Q: How about on PCC pavements? A: Hit any key to have the list of PCC problems appear.

Pavement Preservation Treatments Crack Sealing Surface Treatments/Seals Chip Seals Micro Surfacing Thin Overlays Cold/Hot In-place Recycling

Pavement Preservation If Right preservation treatments are applied at the Right time on the Right road, the pavement will have a longer service life, at less cost.

Pavement Preservation QUESTIONS?