Contents

1. Executive Summary..................................................................................      1

Description................................................................................................      1

Applications...............................................................................................      1

Benefits.....................................................................................................      1

Limitations.................................................................................................      2

Costs                                                                                                          2

Recommendations for Use...........................................................................      2

Point of Contact.........................................................................................      3

2. Preacquisition..........................................................................................      4

Description of Resin Modified Pavement.......................................................      4

Background................................................................................................      5

Applications...............................................................................................      6

Design Methods..........................................................................................      6

Materials....................................................................................................      8

Open-graded AC....................................................................................      8

Resin modified grout..............................................................................      9

Construction Techniques...........................................................................    12

Open-graded AC..................................................................................    12

Resin modified grout.............................................................................    13

Curing.................................................................................................    16

Benefits....................................................................................................    20

Limitations...............................................................................................    20

Costs                                                                                                        21

3. Acquisition/Procurement.........................................................................    24

Potential Funding Sources..........................................................................    24

Technology Components and Sources.........................................................    25

Procurement Documents...........................................................................    26

Technical reports.................................................................................    26

Applicable specifications.......................................................................    26

Vendor list and recent prices..................................................................    26

Procurement Scheduling............................................................................    27

4. Post Acquisition.....................................................................................    28

Initial Implementation................................................................................    28

Equipment...........................................................................................    28

Materials.............................................................................................    28

Personnel............................................................................................    29

Procedure................................................................................................    29

Operation and Maintenance........................................................................    30

Service and Support Requirements..............................................................    30

Performance Monitoring............................................................................    30

References....................................................................................................    31

Appendix A:  Fact Sheet.................................................................................   A1

Appendix B:  Guide Specification for Military Construction.................................    B1

List of Figures

Figure 1.        Schematic of Marsh flow cone...................................................    11

Figure 2.        Asphalt paver placing open-graded asphalt mixture........................    12

Figure 3.        Rolling open-graded asphalt mixture with

small roller................................................................................    13

Figure 4.        Catching sample of grout from truck...........................................    14

Figure 5.        Filling Marsh flow cone with grout sample...................................    15

Figure 6.        Measuring grout viscosity with Marsh flow cone..........................    16

Figure 7.        Pouring grout onto open-graded material......................................    17

Figure 8.        Strips of lumber used to separate grouting lanes............................    17

Figure 9.        Squeegeeing excess grout over open-graded material.....................    18

Figure 10.      Small steel wheel roller vibrating grout into voids..........................    18

Figure 11.      Removing excess grout from finished RMP surface......................    19

Figure 12.      Typical appearance of completed RMP surface.............................    19

Figure 13.      Comparative pavement thickness profiles and

design costs..............................................................................    22

List of Tables

Table 1.         RMP Project Locations in the United States....................................      7

Table 2.         Open-Graded Mixture Aggregate Gradation....................................      9

Table 3.         Resin Modified Cement Grout Mixture Proportions.......................    10

Table 4.         Slurry Grout Viscosity Requirements...........................................    15

 

1     Executive Summary

Description

Resin modified pavement (RMP) is a composite pavement surfacing that uses a unique combination of asphalt concrete (AC) and portland cement

concrete (PCC) materials in the same layer.  The RMP material is generally described as an open-graded asphalt concrete mixture containing 25° to 35°percent voids which are filled with a resin modified portland cement grout.  The open-graded asphalt mixture and resin modified cement grout are pro­duced and placed separately.  The open-graded mixture is produced in a typi­cal

asphalt concrete plant and placed with standard asphalt paving equipment. 

After the open-graded layer has cooled, the slurry grout is poured onto the

porous surfacing and vibrated into the internal voids.  The RMP layer is typi­cally 50 mm (2 in.) thick and has a surface appearance similar to a rough-

textured PCC.

Applications

The RMP process is applicable to new pavement construction as well as reha­bilitation of existing pavement structures.  A new RMP layer may be

plac­ed as an overlay over existing flexible or rigid pavements.  The RMP is suitable to carry heavy and abrasive traffic loads and it is resistant to damage from fuel and chemical spills.  Successful RMP applications are documented for various low-speed traffic areas, such as airport aprons and taxiways, low­speed roadways, industrial and warehouse floorings, fuel depots, rail­ways sta­tions, and port facilities.

Benefits

RMP provides a tough and durable pavement surface that resists rutting caused by heavy channelized traffic loads, surface abrasion caused by tracked vehicle traffic, and deterioration due to fuel spillage.  The jointless surface is simple to construct and requires little to no maintenance effort.  Performance records in the United States indicate that RMP is suitable for practically any environmental condition.

Limitations

RMP should only be used for relatively low-speed traffic applications.  The surface texture can be irregular, resulting in areas of variable skid resis­tance.  The irregular surface texture can also be unsightly when compared to a typical PCC surfacing with a relatively uniform surface texture.  Construc­tion experi­ence is somewhat limited, which causes paving production rates to start off slowly at the beginning of most projects.

Costs

The cost of a 50°mm°thick RMP layer is currently about $9.60 to 19.20 per square meter ($8 to 16 per square yard) as compared to a typical cost of $3.60 to 6.00 per square meter ($3 to 5 per square yard) for a 50°mm°thick layer of dense-graded AC.  The initial cost of a full-depth RMP design is generally 50 to 80 percent higher than a comparable AC design when considering a heavy-duty pavement.  A more important cost comparison is between the RMP design and the rigid pavement design, since the RMP is usually used as a cost-saving alternative to the stan­dard PCC pavement.  In the case of a standard military heavy-duty pavement applica­tion, the RMP design is generally 30 to 60 percent less in initial cost than a comparable PCC pavement design.  In many circum­stances, the RMP also provides cost savings from reduced or eliminated main­tenance efforts when compared to other pave­ment surfacing alternatives.

Recommendations for Use

RMP is recommended for any newly constructed or rehabilitated pavement carrying low-speed traffic (less than 65 kilometer/hr or 40 mile/hr).  RMP can be an ideal cost-saving alternative to PCC pavements where resis­tance to heavy loads, tracked vehicle traffic, or fuel spillage is required.  The available guide specification should be followed closely and the recommended quality control practices should be followed at all times during construction.

 

Point of Contact

Point of contact regarding this technology is:

 

Technical:

 

U.S.Army Engineering Research and Development Center

Waterways Experiment Station

ATTN:  CEWES°GP°Q (Dr. Gary L. Anderton)

3909 Halls Ferry Road

Vicksburg, MS  39180

Telephone:  601°634°2955

Facsimile:  601°634°3020

 

2     Preacquisition

Description of Resin Modified Pavement

 

RMP is a relatively new type of pavement process in the United States that uses a unique combination of AC and PCC materials in the surface layer.  The RMP layer is generally described as an open-graded AC mixture contain­ing 25° to 35°percent voids which are filled with a resin modi­fied cement grout.  The open-graded asphalt mixture and resin modified cement grout are produced and placed separately.  The RMP is typically a 50°mm°thick layer placed on top of a flexible pavement substructure when newly constructed.  This same thickness may be placed on existing flexible or rigid pavement structures as well.  RMP provides performance benefits attrib­utable to both its AC and PCC material properties at a cost somewhere between the typical AC and PCC ranges.

 

The open-graded asphalt mixture is designed to be the initial “skeleton” of the RMP.  A coarse aggregate gradation with very few fines is used along with a low asphalt cement content (typically 3.5 to 4.5 percent by total weight) to produce 25° to 35°percent voids in the mix after construction.  The open-graded asphalt mixture can be produced in either a conventional batch plant or drum-mix plant and is placed with typical AC paving equipment.  After placing, the open-graded asphalt material is smoothed over with a mini­mal number of passes from a small (3°tonne maximum) steel-wheel roller.

 

The resin modified cement grout is composed of fly ash, silica sand, cement, water, and a cross polymer resin additive.  The resin additive is gener­ally composed of five parts water, two parts cross polymer resin of styrene and butadiene, and one part water-reducing agent.  The slurry grout water/cement ratio (w/c) is between 0.65 and 0.75, giving the grout a very fluid consistency.  The cement grout material can be produced in a conven­tional concrete batch plant or a small portable mixer.  After the asphalt mix­ture has cooled, the slurry grout is poured onto the open-graded asphalt material and squeegeed over the surface.  The slurry grout is then vibrated into the voids with the 3°tonne vibratory steel-wheel roller to ensure full penetration of the grout.  This process of grout application and vibration continues until all voids are fill­ed with grout.

 

Depending upon the specific traffic needs, the freshly grouted surface may be hand broomed or mechanically textured to improve skid resistance.  Spray°on curing compounds, typical to the PCC industry, are generally used for short-term curing.  The new RMP surfacing usually achieves full strength in 28 days, but it may be opened to pedestrian traffic in 24 hours and light au­tomobile traffic in 3 days.

 

Background

The RMP process was developed in France in the 1960's as a fuel and abrasion resistant surfacing material.  The RMP process, or Salviacim pro­cess as it is known in Europe, was developed by the French construction company Jean Lefebvre Enterprises as a cost-effective alternative to PCC (Roffe 1989a).  RMP has been successfully marketed throughout France as a pave­ment and flooring material in numerous applications.  By 1990, Jean Lefebvre Enter­prises had successfully placed over 8.3 million square meters (10 mil­lion squa­re yards) of Salviacim pavement in France (Jean Lefebvre Enterprise 1990).  Today, RMP is an accepted standard paving material throughout France.

 

Soon after the RMP process became successful in France, its use in other countries began to grow.  In the 1970's and 1980's, RMP usage spread through­out Europe and into several countries in Africa, the South Pacific, the Far East, and North America (Ahlrich and Anderton 1991a).  Twenty-five coun­tries around the world had documented experience with RMP by 1990 (Jean Lefebvre Enterprise 1990).

 

The earliest documented experience with RMP in the United States occurred in the mid°1970's when the U.S. Army Engineer Waterways Experi­ment Sta­tion (WES) conducted limited evaluations of an RMP test section constructed in Vicksburg, MS (Rone 1976).  The study was conducted to evaluate the effec­tiveness of the new surfacing material to resist damage caused by fuel and oil spillage and abrasion from tracked vehicles.  The evalu­ation results indicated that the effectiveness of the RMP was very con­struction sensitive, and if all phases of design and construction were not performed correctly, the RMP pro­cess would not work.

 

In 1987, the U.S. Army Corps of Engineers tasked WES to reevaluate the RMP process for potential military pavement applications, since the field expe­riences in Europe continued to be positive and improved materials and con­struction procedures had been reported.  WES engineers conducted litera­ture reviews, made site evaluations in France, Great Britain, and Australia, and con­structed and evaluated a new test section at WES (Ahlrich and Ander­ton 1991b).  The results of this evaluation were favorable, prompting pilot projects at several military installations in the following years.  The Federal Aviation Administration (FAA), also eager to develop an alternative paving material tech­nology, used the positive WES experiences and preliminary guidance to construct several pilot projects at commercial airports (Ahlrich and Anderton 1993).  Today, the RMP process is recommended as an alterna­tive pavement surfacing material by the U.S. Army, the U.S. Air Force, U.S. Navy, and the FAA.

 

Applications

RMP may be used in new pavement construction or in the rehabilitation of existing pavement structures.  A new RMP surfacing may be placed as an over­lay over existing flexible or rigid pavements.  RMP is typically used as a low-cost alternative to a PCC rigid pavement or as a means of improving the pave­ment performance over an AC surfaced flexible pavement.  Field experi­ence indicates that RMP may be used in practically any environmental conditions.

 

In general, the RMP is best suited for pavements that are subjected to low-speed traffic that is channelized or abrasive by nature.  Pavement areas with heavy static point loads and heavy fuel spillage are also ideal RMP appli­cation candidates.  The RMP process has been used in a variety of applica­tions on the international market, including airport and vehicular pavements, industrial and warehouse floorings, fuel depots and commercial gasoline sta­tions, city plazas and malls, railway stations, and port facilities.  Since its first commer­cial appli­cation in the Unites States in 1987, RMP has been used mostly on airport and airfield pavement projects.  A listing of the known RMP projects in the United States is given in Table 1.

 

Design Methods

The current practice for designing the RMP layer thicknesses involves a simple adaptation of the standard Corps of Engineers (CE) flexible pavement design method (Headquarters, Departments of the Army and Air Force 1989 and 1992).  The pavement is designed as if it were a typical dense-graded AC surfaced pavement, and then the top 50 mm of AC is substituted with an equal thick­ness of RMP.  Equating the RMP material with AC undoubtedly renders an over-designed pavement in terms of the strength and durability provided by the surfacing.  A recent study conducted under the Strategic Highway Research Program (SHRP) on potential new bridge deck materials showed that the RMP material had approximately a two-fold increase in Marshall stabi­lity, indirect tensile strength, and resilient modulus when compared to a typical high-quality AC material (Al°Qadi, Gouru, and Weyers 1994).  Even with the new SHRP results, there are not enough data on the engineering properties of the RMP to develop a suitable mechanistic design methodology.  Until such a mechanistic design method is developed, the current method of adapting the results of the standard CE flexible pavement design will continue to be used.

 

 

Table 1

RMP Project Locations in the United States

 

Location

 

Area (m2)

 

 Date of Construction

 

Newark Airport, NJ

  (Aircraft Apron)

 

420

 

May 1987

 

Springfield, VA

  (GSA Parking Lot)

 

1,670

 

Oct 1988

 

Vicksburg, MS

  (WES Test Sec­tion)

 

835

 

Aug 1989

 

Orange County, CA

  (Aircraft Taxiway)

 

8,350

 

Oct 1990

 

Tampa International Airport, FL

  (Aircraft Apron)

 

3,350

 

Jan 1991

 

Miami International Airport, FL

  (Aircraft Apron)

 

3,350

 

Jan 1991

 

Concord, CA

  (Port Facilities)

 

4,170

4,170

70,000

 

Jun 1991

Oct 1993

      1995

 

McChord AFB, WA

  (Loading Facilities)

 

8,350

 

Aug 1991

 

Fort Campbell AAF, KY

  (Aircraft Apron)

 

6,250

 

Aug 1992

 

Malmstrom AFB, MT

  (Fuel Storage Areas)

 

10,835

 

Jun 1993

 

Fort Belvoir, VA

  (Loading Facilities)

 

8,350

 

Jun 1994

 

Pope AFB, NC

  (Aircraft Aprons)

 

29,170

 

Jun 1994

 

Altus AFB, OK

  (Aircraft Taxiway)

 

10,500

 

Jun 1995

 

 

RMP has been successfully constructed as an overlay material over rigid and flexible pave­ments as well as in original construction.  No transverse or longitudinal joints are required for original, full-depth RMP designs, although joints have been cut in RMP when overlaying jointed concrete pavement.  Pave­ment joints are required between RMP and adjacent PCC pavements but are not required between RMP and adjacent AC pavements.  These joints are constructed by saw cutting to the bottom of the RMP layer, once the RMP ma­terial has sufficiently cured, and then filling the joint with a sealant mate­rial suitable for the particular site conditions.

 

Materials

 

Open graded AC

  Aggregates.  The aggregates used in the open-graded AC must consist of sound, tough, durable particles crushed and sized to provide a relatively uni­form gradation.  The aggregates are tested against standard Los Angeles abra­sion, sodium sulfate soundness, percent fractured faces, and percent flat and elongated requirements (Headquarters, Department of the Army 1993).  These requirements help to ensure a stable, open-graded asphalt layer with a high in­ternal void structure.  The general requirement is 25° to 35°percent voids in the compacted mixture.  Any amount less than this might not allow the slurry grout to fully penetrate the open-graded mixture, resulting in a structurally unsound surface course which would likely deteriorate under traffic rather quickly.  Void contents greater than this amount would increase the cost of the pavement without providing significant structural improvements and could also reduce the pavement strength by eliminating some of the aggregate to aggre­gate interlock.

 

Asphalt cement.  The type or grade of asphalt cement used in the open-grad­ed AC is not very critical, since the asphalt cement has a limited role in the pavement's performance once the slurry grout has filled all of the void spaces.  The asphalt cement is required to be a paving grade material, how­ever, with an original penetration of 40 to 100.  Asphalt cements within this penetration range are typically categorized by American Society for Testing and Materials (ASTM) D 3381 as an AC°10, AC°20, or AC°30 viscosity grade (ASTM 1995a).  These asphalt cement grades are generally considered to be of medium viscosity.  Lower viscosity asphalt cements could drain off of the large aggre­gates during mixing and transporting, which would reduce  the permeability of the open-graded layer and hinder grout penetration.  Asphalt cements stiffer (or higher viscosity grade) than the specified range might not allow for sufficient coating of the aggre­gates with the typical low asphalt contents used.

 

Mix design.  The object of the open-graded AC mix design is to determine an aggregate gradation and asphalt content which will provide a compacted layer containing 25° to 35°percent voids.  Sieve analyses of pro­posed aggre­gate stockpiles provide the necessary information for an aggregate gradation design.  The gradation requirements of the final blended aggregates to be used in the open-graded mixture are given in Table 2.

 

An estimate of the optimum asphalt content is made to determine a suit­able range of­ asphalt cement contents for a subsequent labora­tory analysis.  The as­phalt content estimate is made using a design equation based on aggre­gate prop­erties (Roffe 1989b).  The design equa­tion is as follows:

 

Table 2

Open°Graded Mixture Aggregate Gradation

 

Sieve Size

 

Per­cent Passing by Weight

 

 19 mm (3/4 in.)

 

  100

 

12.5 mm (1/2 in.)

 

54°76

 

  9.5 mm (3/8 in.)

 

38°60

 

  4.75 mm (No. 4)

 

10°26

 

  2.36 mm (No. 8)

 

  8°16

 

  600 μm (No. 30)

 

  4°10

 

  75 μm (No. 200)

 

  1°3

 

 

Optimum asphalt content = 3.25 aS0.2

 

where

  a  = 2.65/SG

SG  = apparent specific gravity of the combined aggre­gates

  S  = conventional specific surface area

= 0.21G + 5.4S + 7.2s + 135f

 G   = percentage of material retained on 4.75 mm sieve

  S  = percentage of material passing 4.75 mm sieve and retained on

    600 μm sieve

  s   = percentage of material passing 600 μm sieve and retained on

    75 μm sieve

  f   = percentage of material passing 75 μm sieve

Once the optimum asphalt content is estimated using this equation, two asphalt contents below this amount and two asphalt contents above this amount are used, along with the estimated optimum, in the laboratory produc­tion and evaluation of 75°mm (6°in.) diameter Marshall specimens.  The open-graded AC specimens are compacted with 25 blows from a 4.5°kg (10°lb) Marshall hand hammer on one side of each specimen.  The temperature of the labora­tory produced asphalt mixture during compaction is usually around 121 C (250 F).  After the laboratory specimens have been compacted and cooled, they are weigh­ed in air and water to determine bulk density and void contents.  The op­timum asphalt content is typically selected where the result­ing void content is nearest to 30 percent.

 

Resin modified grout

 

Standard ingredients.  The standard ingredients in the resin modified grout include four materials common to PCC production:  portland cement, sand, fly ash, and water.  No special requirements on portland cement are neces­sary for a quality grout.  A Type I cement should be used unless special con­ditions re­quire another cement type.  A clean, sound, durable, and angular silica sand with a gradation between the 1.18 mm (No. 16) sieve and 75 μm (No. 200) sieve is specified to provide a high quality sand that will stay in suspension in the grout during mixing and application.  An ASTM C 618 Type F or “nonhydraulic” fly ash (ASTM 1995b) is used to help provide a consistent grout viscosity without speeding up the grout's rate of setting.  Water is added to the grout in an amount that renders a w/c ratio from 0.65 to 0.70.  The allowable tolerances for the resin modified grout mix propor­tions are given in Table 3.

 

 

 

Table 3

Resin Modified Cement Grout Mixture Proportions

 

Material

 

Percent by Weight

 

Type I Cement

 

 34°40

 

Silica Sand

 

 16°20

 

Fly Ash

 

 16°20

 

Water

 

 22°26

 

Resin Additive

 

2.5°3.5

 

 

Resin additive.  The resin additive used in the slurry grout is a proprietary material produced in the United States by the Alyan Cor­poration under the in­ternational trade name Prosalvia°7 or PL7.  The additive is generally com­posed of five parts water, two parts of a cross polymer resin of styrene and butadiene, and one part water reducing agent.  The additive significantly aids the construc­tion process by acting as a super-plasticizer in reducing the grout viscosity.  The reduced grout viscosity allows the grout to fully penetrate the open-graded asphalt concrete layer more easily.  The additive also increases the flexural and compressive strength of the hardened grout, improves the grout's chemical and abrasion resistance, and reduces the grout's permeability after curing.

 

Mix design.  The goal of the slurry grout mix design is to determine the proportions of mix ingredients that will produce a slurry grout of the proper viscosity.  Grout viscosity is measured by the Marsh flow cone (schematically shown in Figure 1).  The Marsh flow cone is used to measure the time of flux of 1 L (0.264 gal) of grout through the cone.  A high flow-time (too thick or viscous) grout does not penetrate the open-graded asphalt layer com­pletely, while a low flow-time grout may not gain sufficient strength and may promote excessive shrinkage cracking and segregation.  Grouts with an accept­able initial viscosity will have a flow time between 8.0 and 10.0 sec.

 

 

 

 

The slurry grout mix design is conducted by preparing individual batch samples in the laboratory and testing them with the Marsh flow cone.  The batch samples are prepared by first dry mixing the cement, sand, and fly ash in a blend­er until thoroughly mixed.  The appropriate amount of water is then added, and the grout mixture is blend­ed for 5 min.  After the 5°min mixing period, the resin additive is added and mixed with the grout for an additional 3 min.  Immediately after the 3°min mixing period, the grout is poured into the Marsh flow cone and tested for viscosity.  The individual components of the grout may be adjusted within the prescribed tolerances to obtain a desired flow time.

 

Construction Techniques

 

Open°graded AC

 

The open-graded AC layer is generally produced and constructed in the same manner as conventional AC pavements.  The mixture may be produced in either a batch plant or drum-mix plant and is usually mixed at about 121 to 135C (250 to 275F).  It is hauled to the construction site in large haul trucks where it is dumped into a standard asphalt paver.  The temperature of the open-graded material when being placed is less critical than for standard AC mix­tures, since densification is not required.  In fact, once the open-graded mixture is placed by the asphalt paver (Figure 2), the surface is simply smoothed over with a small 3°tonne steel wheel roller (Figure 3).  Usually, one roller pass when the open-graded material has cooled to about 71 C (160 F) and one roller pass at about 55 C (130 F) is all that is needed to com­plete the open-graded asphalt construction phase.

 

 

Resin modified grout

  

The resin modified slurry grout material may be produced at a concrete batch plant for larger projects or with portable concrete mixers for smaller pro­jects.  For the typical batch plant-produced grout, the proper proportions of cement, sand, fly ash, and water are dumped into transit mix trucks and mixed for 5 min.  When the haul distance from the concrete batch plant to the job site is less than 20 min, the cross polymer resin is poured into the mixing drum at the plant site.  The slurry grout is continuously mixed in transit and until actual application to prevent the sand material from settling out of the slurry grout mixture.  Once the transit mix truck reaches the job site, the mixing drum is rotated at maximum speed for an additional 10 min to ensure complete mixing of the slurry grout.  If the haul distance from the concrete batch plant to the job site is greater than 20 min, then the cross pol­ymer resin is added at the job site, followed by an additional 10 min of mix­ing before application.

 

Before placement, a sample of grout from each truck is taken and tested again­st the appropriate Marsh flow cone viscosity requirement (Figures 4, 5, and 6).  The appropriate grout viscosity range depends upon the amount of time passed after addition of the resin additive.  The slurry grout viscosity require­ments are listed in Table 4.

 

Once the slurry grout has passed the viscosity test, it is poured onto the sur­face of the open-graded asphalt material from the pivoting delivery chute of the transit mix truck (Figure 7).  The slurry grout is applied until the area is


 

fully saturated.  When an area becomes saturated, the transit mix truck moves forward, continuing the grout application.  Grout placement is usually con­ducted in wide lanes (3 to 6 m or 15 to 20 ft) separated by strips of lum­ber (Fig­ure 8).  Grout application in this manner provides an orderly approach and keeps the grout from spilling over onto previously grouted areas.  For small projects when the grout is mixed on site in portable mixers, a quick wheelbar­row delivery is suitable.

 

Hand-operated squeegees are used to push and pull the excess slurry grout material to the under-saturated areas (Figure 9).  When the open-graded asphalt material is designed and constructed properly, the majority of the internal voids are quickly filled by gravity upon initial grout application.  Immediately after placing the grout, the small 3°tonne steel wheel roller

 

 

 

 

Table 4

Slurry Grout Viscosity Requirements

 

Time Elapsed after Addi­tion of PL7, min

 

Marsh Flow Cone Viscosity, sec

 

  0°5

 

8°10

 

>15

 

9°11


 

 

 

makes several vibratory passes over the grout filled pavement (Figure 10).  The vibratory action of the roller ensures that the grout is filling all of the accessible internal voids.  After an area is saturated with grout and the voids are completely filled, the excess grout is squeegeed off to produce the desired final surface texture (Figures 11 and 12).

 

 

Curing

 

 

 

Experience has indicated that the short-term curing protection provided by membrane-forming curing compounds is sufficient for the typical RMP pro­ject.  The curing compound is typically white-pigmented to reflect the sun's

 

 

 

 

rays.  The suggested application rate is 1 L/14 m2 (1 gal/400 ft2), which is about one-half of the typical rate used for PCC pavements.  Portable hand ap­plication of curing compound is allowable immediately after grout place­ment (when foot tracking is not a problem) since the open-graded asphalt layer pro­vides enough strength to immediately support light loads.

 

Benefits

RMP provides many of the more attractive benefits associated with both AC and PCC.  It offers the ease of construction, the jointless surface, and the cost competitiveness of an AC material.  It has the fuel, abrasion, and wear resis­tance of a PCC.  RMP has successfully demonstrated resistance to per­manent deformation damage from heavy, high-pressure tire loads.  It has also proven its capability in carrying tracked vehicle traffic by resisting the abra­sive action of the turning tracks (Ahlrich and Anderton 1991b).  The RMP material is well-suited for practically any environment, as evidenced by its international history in regions ranging from the Scandinavian countries to the deserts of Saudi Arabia (Jean Lefebvre Enterprise 1990).

 

Limitations

RMP should only be used for relatively low-speed (less than 65 km/hr or 40 mile/hr) traffic applications.  Initial construction expe­rience indicates that the surface texture of RMP can be irregular, with some areas containing excess grout on the surface.  These areas may have a reduced skid resistance, espe­cially at the beginning of the pavement's life.  Skid resistance improves during the life of an RMP as surface grout is worn away, exposing the sur­face of the large-stone open-graded material.  When skid resistance is a critical factor, sur­face texturing (brooming) immediately after grout application has been used successfully.

 

Because of the fluidity of the slurry grout, it is very difficult to construct an RMP surfacing on steep pavement slopes.  The practical limit for the sur­face slope of an RMP section is 2 percent.  Pavement slopes slightly higher than 2 percent can be constructed, but excess hand work and grout overruns are to be expected.

 

Since the RMP is a relatively new paving process in the United States, the design and construction experience is somewhat limited.  As previously dis­cussed, the current thickness design approach is highly empirical with little known about the engineering properties of the RMP material.  The lack of con­struction experience in the United States usually increases the construction time on most projects.  Construction and evaluation of test sections are important to ensure that the production of paving materials meets the specified job-mix for­mulas.  Test sections also allow the contractor's paving crews to become famil­iar with the unique RMP construction techniques.  Even with a thorough test section evaluation, full-scale RMP production rates generally start off slowly at the beginning of most projects and increase substantially as the construction process continues.

 

Costs

 

The initial construction costs of RMP generally fall somewhere between those of an AC pavement design and a PCC pavement design.  In most instances, the RMP pavement design cost will be closer to the AC pavement design cost than to the PCC pavement design cost.  Bid experiences from re­cent RMP construction projects indicate a current cost of about $9.60 to 19.20 per square meter ($8 to $16 per square yard) of 50°mm-thick RMP sur­facing.

 

A cost comparison of AC, PCC, and RMP designs for two hypothetical pavement systems is provided to illustrate the typical differences in first costs for these three pavement types.  Pavement designs were conducted using stan­dard CE design methodologies (Headquarters, Departments of the Army and Air Force 1989 and 1992).  Flexible and rigid airfield designs were con­ducted using the following input data:

 

Design Traffic = C°141 Aircraft at 156,109 kg (345,000 lb)

Design Passes = 100,000

No frost penetration considered

Subgrade California Bearing Ratio (CBR) = 10

Modulus of Subgrade Reaction (K) = 5.5 x 106 kg/m3 (200 lb/in.3)

Subbase CBR = 40

Base CBR = 100

Rigid Design Base Thickness = 200 mm (8 in.)

PCC Flexural Strength = 5.2 MPa (750 lb/in.2)

 

Flexible and rigid road designs were also conducted for the same condi­tions, except for the following design parameters:

 

Traffic Design Index = 8

Base CBR = 80

Rigid Design Base Thickness = 100 mm (4 in.)

 

The thickness profiles resulting from these hypothetical pavement designs are collectively illustrated in Figure 13.

The pavement cost in terms of dollars per square meter for each 25 mm of thickness was based on the following cost assumptions:

 

Asphalt Concrete = $2.40/sq m

Portland Cement Concrete = $4.80/sq m

Resin Modified Pavement = $7.20/ sq m

100 CBR Base = $0.60/sq m


80 CBR Base = $0.48/sq m

40 CBR Subbase = $0.30/sq m

 

A quick comparison of the construction costs for these two hypothetical pavement design examples indicates the typical cost of RMP relative to the two standard pavement types:  AC and PCC.  Cost savings for the RMP designs versus the PCC designs are significant in each of these cases.  This cost analy­sis clearly illustrates a critical design principal for RMP as an alter­native pave­ment surfacing, namely:

 

When an AC surfacing cannot effectively meet the pavement perfor­mance requirements where both an RMP and PCC surfacing can, then the RMP alternative will generally provide significant initial cost savings in terms of total thickness design costs.

 

In addition to the initial cost savings for using an RMP design instead of a PCC design, an RMP surfacing can be expected to cost much less in terms of maintenance expenditures given a proper design.  The most significant main­tenance cost savings will result from the lack of joints to maintain and reseal with the typical RMP surfacing.  These cost savings will obviously not apply to situations where RMP is overlaid over jointed PCC pavements and joints are cut in the RMP surfacing to trace the PCC joints.


 

3     Acquisition/Procurement

 

Potential Funding Sources

Typically, installations fund the implementation of pavements and rail­roads technologies from their annual budgets.  However, the installation's annual budget is usually underfunded and the pavements and railroads pro­jects do not compete well with other high-visibility or high-interest type projects.  As a re­sult, it is prudent to seek out additional funding sources when the project merits the action.  Listed below are some sources commonly pursued to fund projects.

 

     a.  Productivity program.  See AR 5°4, Department of the Army Produc­

         tivity Improvement Program (Headquarters, Department of the Army

         1982) forguidance to determine if the project qualifies for this type of

         funding.

 

    b.  Facilities Engineering Applications Program (FEAP).  In the past, a

        number of pavement and railroad maintenance projects located at vari­ous

        installations were funded with FEAP demonstration funds.  At that time,

        emphasis was plac­ed on demonstrating new technologies to the Director

        ate of Engineering and Housing (DEH) community.  Now that these

        technologies have been demonstrated, the installations will be responsible

        for funding their projects through other sources.  However, emphasis

        concerning the direction of FEAP may change in the future; therefore,

        one should not rule out FEAP as a source of funding.

 

    cSpecial programs.  Examples of these are as follows:

         (1)   FORSCOM mobilization plan which may include rehabilitation or

               enlargement of parking areas and the reinforcement of  bridges.

              

         (2)   Safety program which may include the repair of unsafe/deteriorated

                railroads at crossings and in ammunition stor­age areas.

 

         (3)   Security upgrade which may include the repair or enlargement of

               fencing.

 

    d.  Reimbursable customer.  Examples of this source are roads to special


         function areas such as family housing or schools and airfield pavements  

         required to support logistical operations.

   

    e.  Special requests from MACOM's.

 

    f.  Year end funds.  This type of funding should be coordinated with the

        MACOM's to ensure that the funds will not be lost after a contract is

        advertised.

 

   g.  Operations and Maintenance Army.  These are the normal funds used for

        funding pavement and railroad projects.

 

Technology Components and Sources

Components of the technology which must be procured for the use of resin modified pavement are:  section design (may be in-house or contracted out) and a contractor to construct the RMP surfacing.  The construction con­tractor must have the materials and mixing plant capable of producing the RMP open-graded asphalt mixture and, if required, a standard dense-graded asphalt mix­ture.  In addition to the standard asphalt paving equipment, the contractor will need a small (3 tonne maximum) steel wheel roller to smooth out the open-graded ma­terial after placement.

 

For the modified slurry grout phase, the construction contractor will need to have access to either a nearby concrete batch plant or one or more portable concrete mixers on site.  The grout batching equipment will depend upon job size and is almost always required to be the larger central batch plant.  Transit mix trucks are needed to transport the grout to the job site and for placement.  Hand squeegees and squeegee operators (typically three to five are sufficient) aid in the grout application.  While the grout is being applied, the small 3°tonne steel wheel roller is used to vibrate the grout into the open-graded layer.  Cur­ing compounds and application equipment typical to the PCC industry are used to complete the RMP construction process.

 

The only unusual material required to produce an RMP surfacing is the resin additive used in the cement slurry grout.  Currently, the resin additive required for grout production (Prosalvia°7 or PL7) is available only from a sin­gle source by contacting the following manufacturer's representative:

 

Alyan Corporation

P.O. Box 788

Vienna, VA  22183

ATTN:  Mr. Ibrahim Murr

Tel: 703-255-1381

FAX: 703-255-1384

 


Procurement Documents

Technical reports

 

The Corps of Engineers has published two technical reports on the research and construction experiences of RMP:

 

“Construction and Evaluation of Resin Modified Pavement,” Technical Re­port GL°91°13, USAE Waterways Experiment Station, 1991 (Ahlrich and Anderton 1991b).

 

“Design, Construction, and Performance of Resin Modified Pavement at Fort Campbell Army Airfield, Kentucky,” Technical Report GL°94°5, USAE Waterways Experiment Station, 1994 (Anderton and Ahlrich 1994).

 

 

Applicable specifications

 

 

 

Several guide specifications are available to provide assistance in complet­ing an RMP construction project.  One of two applicable guide specifications is to be used for the construction of the AC layer beneath the RMP surfacing (unless the RMP is to be overlaid directly over an existing pavement surface).  The choice of asphalt concrete specifications will depend upon the traffic require­ments.  There is also a guide specification available for the construc­tion of the RMP layer itself.  These specifications are as listed below:

 

CEGS°02551, “Bituminous Paving for Roads, Streets, and Open Stor­age Areas (Central Plant Hot Mix),” Department of the Army, Corps of Engi­neers Guide Specification, Washington, DC, April 1989 (Headquarters, Department of the Army 1989).

 

CEGS°02556, “Asphaltic Bituminous Heavy-Duty Pavement (Central-Plant Hot Mix),” Department of the Army, Corps of Engineers Guide Specification, Washington, DC, June 1991 (Headquarters, Department of the Army 1991).

 

CEGS°02548, “Resin Modified Pavement,” Department of the Army, Corps of Engineers Guide Specification, Washington DC, October 1993 (Headquarters, Department of the Army 1993).

 

GSA listing

 

None

 

 

Vendors list and recent prices

 

 

 


Local contractors with experience in AC paving and PCC production should be able to successfully construct an RMP.  Recent RMP construction projects indicate a price range of $9.60 to 19.20 per square meter ($8 to 16 per square yard) for a 50°mm° (2°in.°) thick RMP layer in place.  Prices for any underly­ing AC, base course, and subbase course layers should be based upon recent local bid experiences.

 

Procurement Scheduling

 

 

 

Normal construction contract schedules should be established that allow ade­quate design and plan preparation time, design and review approval, con­tract preparation, advertising and award, and construction time.  A typical pavement project is designed 1 to 2 years before it is constructed; however, plans and specifications for relatively small projects can be completed within a few months.  Once construction is completed, the new RMP surfacing usually achieves full strength in about 21 days, but it may be opened to pedestrian traf­fic in 24 hr and light automobile traffic in 3 days.


 

4     Post Acquisition

 

 

 

 

 

Initial Implementation

 

 

 

Equipment

 

 

 

Conventional AC mixing plant and paving equipment are used to construct the RMP open-graded layer.  One or two small (3°tonne maximum) steel wheel rollers are used to finish the open-graded layer after paving.  Polyethy­lene sheeting is required to protect the open-graded layer from rain when inclement weather is expected before the grout is applied.

 

The modified slurry grout is typically batched in standard concrete batch plants unless the pavement area is small enough to warrant portable batch mix­ing equipment.  For the typical plant-mixed grout scenario, transit mixer trucks are used to carry the grout to the job site and place the grout onto the pavement.  If the portable mixing equipment is used, wheelbarrows may be used to dump the grout onto the pavement.  In either case of grout place­ment, hand-operated squeegees are used to spread the grout around as it is being placed.  The small, 3°tonne steel wheel roller is used in the vibratory mode to promote full penetration of the grout into the open-graded layer during the grouting operation.  Curing compound is applied to the finished RMP surface by means of a mechanical or hand-operated pressurized spraying apparatus.

 

 

Materials

 

 

 

The materials required for the production of an RMP open-graded AC layer are basically the same as those required for typical AC production.  The slurry grout materials are also fairly common to the paving industry, with the excep­tion of the resin additive.  The resin additive is a specialized formulation of a styrene-butadiene polymer latex, which serves as a plasticiz­ing and strength­ening agent in the cement grout.  The resin additive is cur­rently avail­able from only one source and is the only known additive with a proven record of suc­cessful use in such a composite pavement material.

 

 


Personnel

 

 

 

The personnel normally required at an AC plant and those required for AC construction are basically the same as those needed for construction of the RMP open-graded AC layer.  Typical personnel required for PCC plant pro­duction and transit mix truck hauling are also virtually the same as those needed for production and transportation of the slurry grout.  The following personnel are generally required for grout application:  two to three transit mixer truck drivers; one mixer truck delivery chute operator; three to four squeegee opera­tors; one vibratory roller operator; one to two personnel to move joint battens and clean grout joints.

 

As time allows, some of the previously mentioned personnel may be used to measure the grout viscosity of each truck batch, apply curing compound, or apply a broom finish to the freshly grouted surface if required.  The quality control testing required for RMP construction is considerably less than for more traditional AC or PCC paving and can be readily handled by one or two personnel from any commercial testing laboratory qualified for both AC and PCC testing.  The exact number of personnel required for an RMP construc­tion project will depend upon project size and other site-specific conditions.

 

Procedure

 

 

 

The general procedure used to construct an RMP pavement includes the

following:

 

    a.  Construct the required subgrade, subbase, base, and dense-graded AC

         layers in a fashion similar to that used for other flexible pavements.

    b.  Construct a 50°mm-thick layer of open-graded AC using typical AC

         paving equipment and a small (3°tonne maximum) steel wheel roller to

         smooth out the open-graded surface.

 

    c.  Allow the freshly placed open-graded material to cool down to at least

         38 C (100 F) before applying slurry grout.  Cover the open-graded layer

         with polyethylene sheeting if rain is imminent.

 

    d.  Secure wooden battens (50°mm by 100°mm or 2°in. by 4°in. strips of

         lumber) to the surface of the cooled open-graded layer to create grouting

         lanes.  Create grouting lanes in the 3.7° to 7.3°m° (12° to 24°ft°) wide

         range to suit the grouting crew size.

 

    e.   Apply slurry grout to open-graded layer from transit mix trucks.

 

     f.  Vibrate the slurry grout into open-graded layer void spaces with several             passes of the vibratory steel wheel roller.   a.        

 


 

 

    g.  Once a sizeable area of the grouting lane is completed, pull excess grout            off of the surface by continuous squeegeeing in one longitudinal direc                tion.  Also, remove wooden battens and clean off excess grout in these              areas with square-blade shovels, stiff-bristled brooms, and/or squeegees.

   

    h.  Once the surface sheen has disappeared from the freshly grouted RMP

         surface, apply curing compound in a manner and in amounts similar to

         that for standard PCC pavement.

Operation and Maintenance

 

 

 

Operations and maintenance on an RMP are similar to that of a PCC pavement.  Under normal circumstances, the only joints for an RMP surfac­ing will be those between the RMP material and any adjacent PCC pavement or building.  Any cracks that may develop should remain hairline-sized, thus re­quiring virtually no maintenance efforts.  Slight wearing off of the surface grout is normal and actually improves skid resistance.  The life expectancy of an RMP surfacing should be approximately 15 to 25 years, depending heavily upon the performance of the underlying pavement layers.

 

Service and Support Requirements

 

 

 

A representative of the Airfields and Pavements Division, Geotechnical Laboratory (GL), WES, should be consulted in the planning and designing of an RMP project.  It is recommended that the job-mix-formula for the open-graded bituminous mixture and the mixture proportions for the grout be pro­duced and/or approved by the appropriate WES representative.  Besides these recommendations, no other special services or support is required to imple­ment or maintain this technology.

 

Performance Monitoring

 

 

 

Installation personnel can monitor and measure the performance of the RMP surfacing by making periodic inspections of the pavement for signs of distress (cracking, raveling, rutting, etc.).  This monitoring of performance would be no more than that required for any AC pavement.  The performance monitoring can be adjusted to fit into existing pavement management systems.  The unique design and combination of materials do not allow for RMP to be classified as a typical flexible or rigid pavement system, however.  This factor  will require an independent pavement classification or category when includ­ing an RMP sur­facing in a pavement management system.


 

References

 

 

 

 

 

Ahlrich, R. C., and Anderton, G. L.  (1991a).  “Evaluation of resin modi­fied paving process,” Transportation Research Board, Transportation Research Record No. 1317, Washington, DC.

 

 

 

               .  (1991b).  “Construction and evaluation of resin modified pave­ment,” Technical Report GL°91°13, U.S. Army Engineer Waterways Experi­ment Station, Vicksburg, MS.

 

 

 

                .  (1993).  “Resin modified pavement in airfield applications.” Pro­ceedings of American Society of Civil Engineers Specialty Conference on Airport Pavement Innovations - Theory to Practice.  New York, NY.

 

 

 

Al°Qadi, I. L., Gouru, H., and Weyers, R. E.  (1994).  “Asphalt portland ce­ment concrete composite:  laboratory evaluation,” American Society of Civil Engineers Journal of Transportation Engineering 120 (1).

 

 

 

American Society for Testing and Materials.  (1995a).  “Viscosity-graded as­phalt cement for use in pavement construction,” Designation:  ASTM D 3381, 1995 Annual Book of ASTM Standards, Vol 04.03, Philadelphia, PA.

 

 

 

                .  (1995b).  “Fly ash and raw or calcined natural pozzolan for use as a mineral admixture in portland cement concrete,” Designation:  ASTM C 618, 1995 Annual Book of ASTM Standards, Vol 04.02, Philadel­phia, PA.

 

 

 

Anderton, G. L., and Ahlrich, R. C.  (1994).  “Design, construction, and per­formance of resin modified pavement at Fort Campbell Army Airfield, Ken­tucky,” Technical Report GL°94°5, U.S. Army Engineer Waterway Experi­ment Station, Vicksburg, MS.

 

 

 

Headquarters, Department of the Army.  (1982).  “Department of the Army Productivity Improvement Program,” Army Regulation AR 5°4, Washington, DC.

 

 

 

Headquarters, Department of the Army.  (1987).  “Bituminous paving for road, street, and open storage areas (Central-Plant hot mix),” Corps of Engineers Guide Specification CEGS°02551, Washington, DC.

 


 

 

Headquarters, Department of the Army.  (1991).  “Aspaltic bituminous heavy-duty pavement (Central-Plant hot mix),” Corps of Engineers Guide Specifi­cation CEGS-02556, Washington, DC.

 

 

 

                .  (1993).  “Resin modified pave­ment surfacing material,” Corps of Engineers Guide Specification CEGS-02548, Wash­ington, DC.

 

 

 

Headquarters, Departments of the Army and Air Force.  (1989).  “Flexible pavement design for airfields,” Army TM 5°825°2/Air Force AFM 88°6, Washington, DC.

 

 

 

                .  (1992).  “Pavement design for roads, streets, walks, and open storage areas,” Army TM 5°822°5/Air Force AFM 88°7, Washing­ton, DC.

 

 

 

Jean Lefebvre Enterprise.  (1990).  Salviacim - principal productions, french and foreign.  Paris, France.

 

 

 

Roffe, J. C.  (1989a).  Salviacim - introducing the pavement.  Jean Lefebvre Enterprise, Paris, France.

 

 

 

                .  (1989b).  Salviacim (annex 1) - the paving process.  Jean Lefebvre Enterprise, Paris, France.

 

 

 

Rone, C. L.  (1976).  “Evaluation of salviacim,” Miscellaneous Paper S°76°20, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS.