Chapter 1IntroductionFrom Maintenance Technical Advisory Guide (MTAG)

Presentation OutlinePurpose of pavement preservation (PP)Definition of PPComponents of PP ProgramPP ConceptEssentials of PP ProgramBenefits of PPRigid Pavement Performance in CaliforniaCommon Rigid Pavement DistressesOrganization of the MTAG

Purpose of Pavement PreservationTo keep good pavements in good or near new conditions by applying the right maintenance strategies that are cost-effective at the right time to extend pavement life and preserve investments.

Definition of Pavement PreservationA 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 (FHWA, 2005).

Components of Pavement Preservation ProgramConsists primarily of three components:preventive maintenanceminor rehabilitation (restoration), and some routine maintenanceDoes not include new pavements or pavements that require major rehabilitation or reconstruction.

Pavement Preservation ConceptA proactive approach in maintaining the existing highways Addresses pavements while they are still in good condition and before the onset of serious damageApplying a cost-effective treatment at the right time to the right pavement to extend pavement life

Essentials of Pavement Preservation ProgramPavement preservation is an agency programAn effective pavement preservation program include agency leadership and a dedicated annual budget, and support and input from staff in planning, finance, design, construction, materials, and maintenance

Benefits of Pavement PreservationBenefits of pavement preservation program:preserving the roadway networkenhancing pavement performanceensuring cost-effectiveness by extending pavement life, and reducing user delays by avoiding rehabilitation or reconstruction. Some of these benefits may be noticed immediately and some may be realized over time

Typical Pavement Performance Curve

Importance of Timely Treatments

Cost Effects of Treatments

Rigid Pavement Performance in CADesign and PerformanceBase support. Initially CTB; later LCB. CTPB and ATPB also used.Slab thickness. In the 1950s, an 8-inch. Later 9-inch slab became common. Presently, 10-inch and even 12-inch thick slabs are used depending on projected traffic.Dowels, tie bars, sealed joints were added in 2000.Causes of Rigid Pavement Deterioration Faulting Mechanism and Effort on Addressing Faulting

Common Rigid Pavement DistressesJoint Deficiencies and CrackingSpallingFaultingJoint seal damageLongitudinal cracksTransverse cracksSlab crackingCorner breakDurability D cracking

Common Rigid Pavement DistressesSurface DefectsScalingSurface polish/polished aggregate Surface attritionPopoutsOther Miscellaneous Distresses Blow-upsPumping and water seepageLane shoulder drop-offSettlement

Spalling at the Joint

Faulting

Longitudinal Crack

Transverse Crack

Slab Cracking

Corner Crack

D Cracking

Scaling

Surface Polish/Polished Aggregate

Severe Surface Abrasion with Third Stage Cracking

Popouts

Blow-ups

Pumping and Water Bleeding

Lane/Shoulder Drop-Off

Factors Affecting JPCP Distress

Factors Affecting JPCP Distress

Materials ConsiderationsConcrete Constituent Materials Cementitious Repair Materials Specialty Repair Materials Bituminous Materials Sealants Dowel Bars and Tie Bars

Design ConsiderationsTraffic Environment TemperatureMoistureOther factorsWindows of OpportunitiesTraffic ControlItem Codes

Organization of MTAGMTAG provides guidance on selecting the most appropriate strategies to address various pavement distresses described earlier by applying pavement preservation treatmentsOrganization of GuideChapter 2 is on Surface characteristicsChapter 3 presents a discussion on strategy selection Chapters 4 through 8 describe various strategies in detail

Chapters Covered in MTAG 2nd Ed

SummaryApplying the Right treatment to the Right pavementat the Right timeis the Core ofPavement Preservation

Base support. Initially, a cement treated base (CTB) was used. This material was later replaced by lean concrete base (LCB) which is a low cement content concrete that could be slip-formed or cast in forms. Caltrans has also used cement treated permeable base (CTPB), which is a concrete base batched with no sand to allow water to pass through the base with ease. Caltrans has also used asphalt treated permeable base (ATPB), which is an asphalt concrete (AC) base with lesser amount of asphalt cement than conventional AC.Slab thickness. In the 1950s, an 8-inch (203 mm) thick slab was the common practice with a few 9-inch (229 mm) slabs. Later on a 9-inch (229 mm) thick slab became common practice. Presently, 10-inch (254 mm) and even 12-inch (305 mm) thick slabs are used depending on projected traffic.Dowels, tie bars, sealed joints were added in 2000.