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Publication Number: FHWA-RD-03-088
Date: November 2003

Introduction to The LTPP Information Management System (IMS)

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The Maintenance (MNT) and Rehabilitation (RHB) modules house very similar and often related data, and are therefore discussed in the same chapter. In the future, it is planned to collapse the MNT and RHB modules into a single module to avoid confusion on where these closely related data types are stored.

Major improvements to a test section after inclusion in the LTPP program are documented in the RHB module. The tables in this module contain information on activities such as overlay properties and construction, shoulder replacement, and joint repair. Rehabilitation activities include resurfacing, reconstruction, and the addition of lanes. Rehabilitation sometimes alters the pavement structure. In these cases, layer data are recorded.

The MNT module contains data reported by highway agencies on maintenance treatments applied to test sections. This module primarily records activities conducted on the test section after inclusion in the LTPP program. However, one table contains information on maintenance treatments applied prior to inclusion of the test section in the LTPP study. While the data in the MNT tables include information such as placement of seal coats, patches, joint resealing, milling , and grooving , users should also examine information stored in the RHB module since these two activities are closely related. Unlike the RHB module, there is no significant pavement structure change from a maintenance event, and therefore no maintenance layer table exists.

Regardless of whether a treatment is considered maintenance or rehabilitation, the pavement structure will always be represented in the appropriate TST tables. Chapter 14 contains more information on TST tables.

Participating highway agencies are requested to notify the LTPP regional office prior to performing maintenance or rehabilitation on a highway segment containing an LTPP section. This allows the regional office to collect any necessary monitoring data to identify the condition of the pavement prior to the activity. Data are collected on pavement condition before and after all rehabilitation and many maintenance activities. States provide information on paper forms describing the actual work done.

Some types of rehabilitation do not fit either the GPS or SPS experiments. Sections receiving those treatments are placed out of study, are no longer studied after rehabilitation, and do not have data in this module for that treatment.

8.1 IMPORTANT FIELDS

IMP_TYPE

provides information on the type of maintenance or rehabilitation performed, and is used in both MNT_IMP and RHB_IMP . The field uses a code named MAINT_WORK. Some of these codes are very similar and, therefore, one type of activity may be represented by different codes in different records.

For SPS maintenance and rehabilitation experiments, much of the data related to the experimental maintenance treatments are stored in tables in the SPS module.

This field should be used to determine which other MNT or RHB tables contain the specifics of the activity. Table 3 shows the general relationships between IMP_TYPE and the MNT and RHB tables. Because of the variability in the maintenance and rehabilitation improvements, and the use of SPS_* tables for some of these data, different tables may be completed for different projects, and data may not be stored in the expected MNT or RHB table for a given IMP_TYPE code. Data may not always be available for a given improvement, and when DATA_AVAIL_IMS is "N", there will be no data in other MNT and RHB tables.

Table 3. IMP_TYPE and expected location of data in MNT and RHB tables.

IMP_TYPE

Improvement Type

Expected Location of Specific Data in MNT and RHB Tables

1

Crack Sealing

MNT_PCC_CRACK_SEAL

MNT_ASPHALT_CRACK_SEAL

2

Transverse Joint Sealing

MNT_PCC_JOINT_RESEAL

3

Lane-Shoulder Longitudinal Joint Sealing

MNT_PCC_JOINT_RESEAL

4

Full-Depth Transverse Joint Repair Patch

MNT_PCC_FULL_DEPTH

5

Full-Depth Patching of PCC Pavement Other Than at Joint

MNT_PCC_FULL_DEPTH

6

Partial-Depth Patching of PCC Pavement Other Than at Joint

MNT_PCC_PART_DEPTH

7

PCC Slab Replacement

MNT_PCC_FULL_DEPTH

8

PCC Shoulder Restoration

RHB_RESTORE_PCC_SHOULDER

9

PCC Shoulder Replacement

RHB_RESTORE_PCC_SHOULDER

10

AC Shoulder Restoration

RHB_RESTORE_AC_SHOULDER

11

AC Shoulder Replacement

RHB_RESTORE_AC_SHOULDER

12

Grinding Surface

MNT_GMC

13

Grooving Surface

MNT_GMG

14

Pressure Grout Subsealing

RHB_SUBSEALING_PCC

16

Asphalt Subsealing

RHB_SUBSEALING_PCC

19

AC Overlay

RHB_ACO_*

RHB_PMA_ *

20

PCC Overlay

RHB_PCCO_*

21

Mechanical Premix Patch

MNT_ASPHALT_PATCH

22

Manual Premix Spot Patch

MNT_ASPHALT_PATCH

23

Machine Premix Patch

MNT_ASPHALT_PATCH

24

Full-Depth Patch of AC Pavement

MNT_ASPHALT_PATCH

25

Patch Pot Holes: Hand Spread, Compacted With Truck

MNT_ASPHALT_PATCH

26

Skin Patching

MNT_ASPHALT_PATCH

27

Strip Patching

MNT_ASPHALT_PATCH

28

Surface Treatment, Single Layer

MNT_ASPHALT_SEAL

29

Surface Treatment, Double Layer

MNT_ASPHALT_SEAL

30

Surface Treatment, Three or More Layers

MNT_ASPHALT_SEAL

31

Aggregate Seal Coat

MNT_ASPHALT_SEAL

32

Sand Seal Coat

MNT_ASPHALT_SEAL

33

Slurry Seal Coat

MNT_ASPHALT_SEAL

34

Fog Seal Coat

MNT_ASPHALT_SEAL

35

Prime Coat

MNT_ASPHALT_SEAL

36

Tack Coat

MNT_ASPHALT_SEAL

37

Dust Layering

MNT_ASPHALT_SEAL

38

Longitudinal Subdrainage

RHB_SUBDRAINAGE

39

Transverse Subdrainage

RHB_SUBDRAINAGE

40

Drainage Blankets

RHB_SUBDRAINAGE

41

Well System

RHB_SUBDRAINAGE

42

Drainage Blankets With Longitudinal Drains

RHB_SUBDRAINAGE

43

Hot-Mix Recycled AC

RHB_HMRAP_*

RHB_PMA_*

44

Cold-Mix Recycled AC

RHB_CMRAP_*

RHB_PMA_*

45

Heater Scarification, Surface-Recycled AC

RHB_HEATER_SCARIF

46

Crack-and-Seat PCC Pavement as Base for New AC Surface

RHB_CRACK_SEAT_PCC

47

Crack-and-Seat PCC Pavement as Base for New PCC Surface

RHB_CRACK_SEAT_PCC

48

Recycled PCC

RHB_RCYPCC_*

RHB_PCCO_*

49

Pressure Relief Joints in PCC Pavements

RHB_PRESSURE_RELIEF

50

Joint Load-Transfer Restoration in PCC Pavements

RHB_LOAD_TRANSFER

51

Mill Off AC and Overlay With AC

RHB_MILL_AND_GRIND

RHB_ACO_*

RHB_PMA_*

52

Mill Off AC and Overlay With PCC

RHB_MILL_AND_GRIND

RHB_PCCO_*

53

Other

 
54

Partial-Depth Patching of PCC Pavements at Joints

MNT_PCC_PART_DEPTH

55

Mill Existing Pavement and Overlay With Hot-Mix AC

RHB_MILL_AND_GRIND

RHB_HMRAP_*

RHB_PMA_*

56

Mill Existing Pavement and Overlay With Cold-Mix AC

RHB_MILL_AND_GRIND

RHB_CMRAP_*

RHB_PMA_*

DATA_AVAIL_IMS in MNT_IMP and RHB_IMP indicates whether information on the maintenance or rehabilitation activity is available in other MNT or RHB tables. The creation of a record in MNT_IMP or RHB_IMP is an important step in the process of assigning a construction number, and this field is necessary so that entries can be made in the MNT_IMP or RHB_IMP tables before the specifics of the activity are known.

8.2 MNT TABLES

MNT_IMP: This table contains a listing of the various maintenance activities conducted on each test section after its inclusion in the LTPP program and the date on which these treatments were applied.

MNT_PCC_CRACK_SEAL: This table contains crack sealing information for PCC pavements, including the type of sealant used, how it was applied, and how much sealing was performed.

MNT_PCC_FULL_DEPTH: This table contains information on full-depth PCC repair, including the reasons for the repair, the size of the replacement slab, the material used for replacement, the interface of the replacement with the existing pavement, and finishing/curing methods.

MNT_PCC_JOINT_RESEAL: This table contains joint resealing information for PCC pavements, including information on the removal of existing joint seal ant, the application and type of the new sealant, and the quantity of sealing performed.

MNT_PCC_PART_DEPTH: This table contains information on partial-depth patching for PCC pavements, including the reasons for patching, the type of patching performed, the material used for patching and material properties, jointing, and curing methods for PCC patches.

MNT_ASPHALT_CRACK_SEAL: This table contains crack sealing information for AC pavements, including the type of sealant used, how it was applied, and how much sealing was performed.

MNT_ASPHALT_PATCH: This table contains patching information for AC pavements, including the reasons for patching, the size of patching, and patching techniques.

MNT_ASPHALT_SEAL: This table contains seal-coat application information for AC pavements, including the reasons for sealing, the type and properties of the sealant used, and application information.

MNT_GMG: This table contains information on diamond grinding , milling , and grooving of all pavement surface types, including the reasons for treatment and the details of the treatment type and application.

MNT_COST: This table contains cost information for maintenance activities. Because of differences in the way highway agencies compute costs, users should expect inconsistencies in cost information.

MNT_HIST: This table contains information on section maintenance that occurred prior to the section's inclusion in the LTPP program, including only basic information such as type and quantity of maintenance.

8.3 RHB TABLES

8.3.1 Nonrehabilitation-Specific Tables

These tables are not specific to any one type of rehabilitation, and may be filled out regardless of the rehabilitation performed. RHB_IMP will be filled out for every rehabilitation event, and RHB_LAYER will be completed only for those rehabilitations that alter the layer structure.

RHB_IMP: This table contains a complete list of the rehabilitation treatments placed after the test section was included in the LTPP program. This table also contains when the treatments were placed.

RHB_LAYER: This table contains changes to the layer structure based on information provided by the State or Provincial highway agency. This information should not be used when conducting analyses on long-term pavement performance; however, it is considered useful when conducting a detailed analysis of an individual section(s).

RHB_CAUSE_INFO: This table contains information on the cause(s) of rehabilitation for a test section and the scheduled start date for the rehabilitation.

8.3.2 RHB Tables for AC Overlays

8.3.2.1 RHB_PMA _* Tables

These tables contain information on the construction of AC overlays. They will be used regardless of whether the overlay is recycled AC or not. They will probably be populated when IMP_TYPE = 19, 43, 44, 51, 55, or 56.

RHB_PMA _COMPACTION: This table contains compaction data for all types of AC overlays, including information on roller types and coverage.

RHB_PMA _CONSTRUCTION: This table contains construction data for all types of AC overlays. This table includes plant information and lay-down temperatures.

RHB_PMA _ROLLER: This table contains roller data for rollers used on all types of AC overlays, including the type, weight, and speed of the rollers used for compaction.

8.3.2.2 RHB_ACO_* Tables

These tables are used for nonrecycled asphalt pavement overlays. They will probably be populated only if IMP_TYPE= 19 or 51.

RHB_ACO_AGGR_PROP: This table contains the properties of the aggregate used in AC overlays, including aggregate composition, durability, specific gravity, and gradation .

RHB_ACO_LAB_AGED_AC: This table contains the properties of the laboratory-aged asphalt cement used in AC overlays, including viscosity, ductility, penetration, and other asphalt cement properties .

RHB_ACO_LAB_MIX: This table contains the properties of the AC laboratory mix design used in AC overlays, including asphalt content , air voids, specific gravity, stability, and other AC properties .

RHB_ACO_MIX_PROP: This table contains the as-placed properties of the AC mix used in AC overlays, including asphalt content , air voids, specific gravity, stability, and other AC properties .

RHB_ACO_PROP: This table contains the properties of the asphalt cement used in AC overlays, including the modifiers used, specific gravity, viscosity, ductility, and other asphalt cement properties .

8.3.2.3 RHB_CMRAP_* Tables

These RHB tables are used for cold-mix recycled AC overlays. They will probably be populated only if IMP_TYPE= 44 or 56. Since this is not a standard treatment option for the LTPP experiments, most of the following tables are empty. Currently, the only table populated in this series is RHB_CMRAP_LAB_MIX, which contains two records.

RHB_CMRAP_COMBINED_AGG: This table contains the properties of the combined aggregate used in cold-mix recycled AC overlays, including aggregate composition, specific gravity, and gradation .

RHB_CMRAP_COMBINE_AC: This table contains the properties of the asphalt cement used in cold-mix recycled AC overlays, including the modifiers used, specific gravity, viscosity, ductility, and other asphalt cement properties .

RHB_CMRAP_GEN_INFO: This table contains the properties of the reclaimed aggregate and general information for cold-mix recycled AC overlays, including the gradation and specific gravity of the reclaimed aggregate, and the methods used to process and break up the existing pavement.

RHB_CMRAP_LAB_AGED_AC: This table contains the properties of the laboratory-aged asphalt cement used in cold-mix recycled AC overlays, including viscosity, ductility, penetration, and other asphalt cement properties .

RHB_CMRAP_LAB_MIX: This table contains the properties of the AC laboratory mix design used in cold-mix recycled AC overlays, including asphalt content , air voids, specific gravity, stability, and other AC properties .

RHB_CMRAP_MIX_PROP: This table contains the as-placed properties of the AC mix used in cold-mix recycled AC overlays, including asphalt content , air voids, specific gravity, stability, and other AC properties .

RHB_CMRAP_NEW_AC_PROP: This table contains the properties of the new asphalt cement used in cold-mix recycled AC overlays, including viscosity, ductility, penetration, and other asphalt cement properties.

RHB_CMRAP_RECLAIM_AC: This table contains the properties of the reclaimed asphalt cement used in cold-mix recycled AC overlays, including viscosity, ductility, penetration, and other asphalt cement properties.

RHB_CMRAP_UNTREAT_AGGR: This table contains the properties of the untreated aggregate used in cold-mix recycled AC overlays, including aggregate composition, durability, specific gravity, and gradation .

8.3.2.4 RHB_HMRAP_* Tables

These RHB tables are used for hot-mix recycled AC overlays. They will probably be populated only if IMP_TYPE = 43 or 55.

RHB_HMRAP_COMBINED_AGG: This table contains the properties of the combined aggregate used in hot-mix recycled AC overlays, including aggregate composition, specific gravity, and gradation .

RHB_HMRAP_COMBINE_AC: This table contains the properties of the asphalt cement used in hot-mix recycled AC overlays, including the modifiers used, specific gravity, viscosity, ductility, and other asphalt cement properties .

RHB_HMRAP_GEN_INFO: This table contains the properties of the reclaimed aggregate and general information on hot-mix recycled AC overlays, including the gradation and specific gravity of the reclaimed aggregate and the methods used to process and break up the existing pavement.

RHB_HMRAP_LAB_AGED_AC: This table contains the properties of the laboratory-aged asphalt cement used in hot-mix recycled AC overlays, including viscosity, ductility, penetration, and other asphalt cement properties .

RHB_HMRAP_LAB_MIX: This table contains the properties of the AC laboratory mix design used in hot-mix recycled AC overlays, including asphalt content , air voids, specific gravity, stability, and other AC properties.

RHB_HMRAP_MIX_PROP: This table contains the as-placed properties of the AC mix used in hot-mix recycled AC overlays, including asphalt content , air voids, specific gravity, stability, and other AC properties .

RHB_HMRAP_NEW_AC_PROP: This table contains the properties of the new asphalt cement used in hot-mix recycled AC overlays, including viscosity, ductility, penetration, and other asphalt cement properties .

RHB_HMRAP_RECLAIM_AC: This table contains the properties of the reclaimed asphalt cement used in hot-mix recycled AC overlays, including viscosity, ductility, penetration, and other asphalt cement properties.

RHB_HMRAP_UNTREAT_AGGR: This table contains the properties of the untreated aggregate used in hot-mix recycled AC overlays, including aggregate composition, durability, specific gravity, and gradation.

8.3.3 RHB Tables for PCC Overlays

8.3.3.1 RHB_PCCO Tables

These tables include information on PCC overlays. These tables will probably be populated when IMP_TYPE = 20, 48, or 52.

RHB_PCCO_AGGR: This table contains the properties of the aggregate used in PCC overlays, including aggregate composition, durability, specific gravity, and gradation.

RHB_PCCO_CONSTRUCTION: This table contains construction data for PCC overlays, including information on curing , temperature, and existing surface preparation.

RHB_PCCO_JOINT_DATA: This table contains joint data for PCC overlays, including information on construction and expansion joints, sealants, and load-transfer devices.

RHB_PCCO_MIXTURE: This table contains PCC mixture data for PCC overlays, including information on mix design, admixtures , slump, air entrainment, and other PCC mix properties.

RHB_PCCO_STEEL: This table contains information on reinforcing steel used in PCC overlay s, including the type and strength of the reinforcement and some placement information.

RHB_PCCO_STRENGTH: This table contains PCC strength data for PCC overlays, including flexural, compressive, and tensile strength, and elastic modulus.

8.3.4 Non-Overlay RHB Tables

These tables contain information on PCC overlays using recycled PCC pavement. These tables will probably be populated when IMP_TYPE = 48. Since recycled PCC overlays were not an LTPP study topic, the tables in this module are currently empty.

RHB_RCYPCC_COMBINED_AGGR: This table contains the properties of the combined aggregate used in recycled PCC overlays, including aggregate durability, specific gravity, and gradation.

RHB_RCYPCC_CONSTRUCTION: This table contains construction data for recycled PCC overlays, including information on curing, temperature, and existing surface preparation.

RHB_RCYPCC_JOINT: This table contains joint data for recycled PCC overlays, including information on construction and expansion joints, sealants, and load-transfer devices.

RHB_RCYPCC_MIXTURE: This table contains PCC mixture data for recycled PCC overlays, including information on mix design, admixtures, slump, air entrainment, and other PCC mix properties.

RHB_RCYPCC_NEW_AGGR: This table contains the properties of the new (nonrecycled) aggregate used in recycled PCC overlays, including aggregate composition, durability, specific gravity, and gradation.

RHB_RCYPCC_STEEL: This table contains information on reinforcing steel used in recycled PCC overlays, including the type and strength of the reinforcement and some placement information.

RHB_RCYPCC_STRENGTH: This table contains PCC strength data for recycled PCC overlays, including flexural, compressive, and tensile strength, and elastic modulus.

8.4 TABLES IN OTHER MODULES

INV_MAJOR_IMP: This table contains data on major maintenance and rehabilitation treatments that were applied to the test section prior to its inclusion in the LTPP program.

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The Federal Highway Administration (FHWA) is a part of the U.S. Department of Transportation and is headquartered in Washington, D.C., with field offices across the United States. is a major agency of the U.S. Department of Transportation (DOT).
The Federal Highway Administration (FHWA) is a part of the U.S. Department of Transportation and is headquartered in Washington, D.C., with field offices across the United States. is a major agency of the U.S. Department of Transportation (DOT). Provide leadership and technology for the delivery of long life pavements that meet our customers needs and are safe, cost effective, and can be effectively maintained. Federal Highway Administration's (FHWA) R&T Web site portal, which provides access to or information about the Agency’s R&T program, projects, partnerships, publications, and results.
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