ufc_3_250_08fa Sealing Joints.pdf

UFC 3-250-08FA

16 January 2004

UNIFIED FACILITIES CRITERIA (UFC)

STANDARD PRACTICE FOR

SEALING JOINTS AND CRACKS IN

RIGID AND FLEXIBLE PAVEMENTS

APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED

UNIFIED FACILITIES CRITERIA (UFC)

STANDARD PRACTICE FOR SEALING JOINTS AND CRACKS IN RIGID AND

FLEXIBLE PAVEMENTS

Any copyrighted material included in this UFC is identified at its point of use.

Use of the copyrighted material apart from this UFC must have the permission of the copyright holder.

U.S. ARMY CORPS OF ENGINEERS (Preparing Activity)

NAVAL FACILITIES ENGINEERING COMMAND

AIR FORCE CIVIL ENGINEER SUPPORT AGENCY

Record of Changes (changes are indicated by \1\ ... /1/)

Change No. Date Location

This UFC supersedes TM 5-822-11, dated 11 June 1993. The format of this UFC does not conform to UFC 1-300-01; however, the format will be adjusted to conform at the next revision. The body of this UFC is the previous TM 5-822-11, dated 11 June 1993.

FOREWORD

\1\ The Unified Facilities Criteria (UFC) system is prescribed by MIL-STD 3007 and provides planning, design, construction, sustainment, restoration, and modernization criteria, and applies to the Military Departments, the Defense Agencies, and the DoD Field Activities in accordance with USD(AT&L) Memorandum dated 29 May 2002. UFC will be used for all DoD projects and work for other customers where appropriate. All construction outside of the United States is also governed by Status of forces Agreements (SOFA), Host Nation Funded Construction Agreements (HNFA), and in some instances, Bilateral Infrastructure Agreements (BIA.)

Therefore, the acquisition team must ensure compliance with the more stringent of the UFC, the SOFA, the HNFA, and the BIA, as applicable.

UFC are living documents and will be periodically reviewed, updated, and made available to users as part of the Services’ responsibility for providing technical criteria for military construction. Headquarters, U.S. Army Corps of Engineers (HQUSACE), Naval Facilities Engineering Command (NAVFAC), and Air Force Civil Engineer Support Agency (AFCESA) are responsible for administration of the UFC system. Defense agencies should contact the preparing service for document interpretation and improvements. Technical content of UFC is the responsibility of the cognizant DoD working group. Recommended changes with supporting rationale should be sent to the respective service proponent office by the following electronic form: Criteria Change Request (CCR). The form is also accessible from the Internet sites listed below.

UFC are effective upon issuance and are distributed only in electronic media from the following source:

• Whole Building Design Guide web site http://dod.wbdg.org/.

Hard copies of UFC printed from electronic media should be checked against the current electronic version prior to use to ensure that they are current.

AUTHORIZED BY:

DONALD L. BASHAM, P.E.

Chief, Engineering and Construction U.S. Army Corps of Engineers

DR. JAMES W WRIGHT, P.E.

Chief Engineer Naval Facilities Engineering Command

KATHLEEN I. FERGUSON, P.E.

The Deputy Civil Engineer DCS/Installations & Logistics Department of the Air Force

Dr. GET W. MOY, P.E.

Director, Installations Requirements and Management Office of the Deputy Under Secretary of Defense (Installations and Environment) http://www.wbdg.org/pdfs/ufc_implementation.pdf https://65.204.17.188/projnet/cms/version2/index.cfm?WORKFLOW=CMS_CCRQAdd&Action=IDFORM&SecureTry=1 http://dod.wbdg.org/

ARMY TM 5-822-11

AIR FORCE AFP 88-6, Chap. 7

TECHNICAL MANUAL

STANDARD PRACTICE FOR

SEALING JOINTS AND CRACKS

IN RIGID AND FLEXIBLE PAVEMENTS

APPROVED FOR PUBLIC RELEASE; DISTRIEWTION IS UNLIMITED

DEPARTMENTS OF THE ARMY AND THE AIR FORCE

JUNE 1993

TM 5-822-11/AFP 88-6, Chap. 7 i

TECHNICAL MANUAL HEADQUARTERS

TM 5-822-11 DEPARTMENTS OF THE ARMY

AIR FORCE MANUAL AND THE AIR FORCE

NO. 88-6, CHAPTER 7 WASHINGTON, D.C., 11 June 1993}

STANDARD PRACTICE FOR SEALING JOINTS AND

CRACKS IN RIGID AND FLEXIBLE PAVEMENTS

Paragraph Page

CHAPTER 1. GENERAL

Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 1-1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 1-1 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 1-1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 1-1

CHAPTER 2. SEALANT MATERIALS

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 2-1 Sealant Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 2-1 Sealant Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 2-1 Sealant Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4 2-4 Backer and Separating Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5 2-4 Shape Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6 2-6 Common Sealant Defects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7 2-9

CHAPTER 3. DETERMINING SEALING NEEDS

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 3-1 Factors to be Considered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 3-1 Condition Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3 3-3 Evaluation to Justify Sealing Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4 3-3 Selecting Appropriate Sealant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5 3-4 Selecting Sealing Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6 3-5

CHAPTER 4. JOINT AND CRACK PREPARATION

Equipment Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 4-1 Preparing New Joints in PCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 4-4 Preparing Old Joints in PCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3 4-5 Preparing Cracks in PCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4 4-8 Preparing Cracks in Bituminous Pavement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5 4-10

CHAPTER 5. JOINT AND CRACK SEALING

Sealing Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 5-1 Application Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2 5-1 Application Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3 5-4

CHAPTER 6. INSPECTION PROCEDURES

Plans, Specifications, and Contracts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1 6-1 Equipment Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2 6-1 Joint Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3 6-2 Sealing Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4 6-4 Final Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5 6-4

APPENDIX A. REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1 APPENDIX B. SEALANT REFERENCE TABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1 APPENDIX C. COMPUTING THE WORKING RANGE OF JOINTS AND SEALANTS . . . . . . . . . . . . . . . . C-1 APPENDIX D. LIFE-CYCLE COST ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-1

LIST OF FIGURES

Figure 2-1. Joint Terminology and Shape Factor.

2-2. Types of Backer Rod Materials.

2-3. Schematics of Backer Materials in the Joints.

2-4. Stresses in Field-Poured Sealants.

2-5. Stresses in Preformed Elastomeric Compression Seals.

2-6. Defects in Field-Poured Sealants.

2-7. Defects in Preformed Elastomeric Compression Seals.

APPROVED FOR PUBLIC RELEASE; DISTRIBUTION IS UNLIMITED

ii

LIST OF FIGURES (cont'd)

Figure 4-1. Concrete Saw Refacing Joint.

4-2. Concrete Saw with a 6-Inch Diameter Blade.

4-3. Joint Plow Removing Old Sealant.

4-4. Sandblasting Equipment Cleaning Joints.

4-5. Waterblasting Equipment Cleaning Joints.

4-6. Vertical Spindle Router.

4-7. Rotary Impact Router.

4-8. Carbide Tipped Bit for Rotary Impact Router.

4-9. Power Vacuum Removing Debris from Pavement Surface.

4-10. Sequence for Sawing New Joints in Fresh Concrete.

4-11. A Freshly Sawn Joint.

4-12. Joint after Sandblasting.

4-13. Backer Rod Protruding above Sealant.

4-14. V-Shaped Plow Tool.

4-15. Spalling Produced During Sealant Removal.

4-16. Example of a Rebuilt Joint.

5-1. Schematics of Different Hot-Applied Sealant Applicators.

5-2. Hot-Applied Sealant Application Equipment.

5-3. Cold-Applied, Two-Component Sealant Application Equipment.

5-4. Cold-Applied, Single Component Sealant Application Equipment.

5-5. Preformed Elastomeric Compression Seal Application Equipment.

6-1. Joint Template.

List of Tables

Table 2-1. Tests Conducted on Each Field-Poured Sealant Type.

3-1. Sealant Condition Rating.

3-2. Pavement Evaluation Checklist.

3-3. Guidance on the Compatibility of Various Sealants.

C-1. Working Range of Joints.

C-2. Working Range of Field-Poured Sealants.

C-3. Working Range of Preformed Elastomeric Compression Seals.

1-1

CHAPTER 1

GENERAL

1-1. Purpose. This manual contains guidance for ensuring the quality of joint and crack sealing or resealing of bituminous and portland cement 1-3. References. Appendix A contains a list of concrete pavement. references used in this manual.

1-2. Scope. Current state-of-the-art tech- 1-4. Background. Sealing joints and cracks in niques and materials are presented in this manual to aid in achieving reduced life-cycle costs by providing information concerning the specifica-tion, use, and quality control of sealants for pave-ments. Sealants covered by Federal Specifications (FS) SS-S-1401C, SS-S-1614A, SS-S-200E, and American Society for Testing and Materials (ASTM) D 2628 are discussed in the following paragraphs. The newer types of sealants which are not covered by the above specifications are not discussed in detail in this manual and must be considered on an individual basis. This manual does not address all of the safety problems associ-ated with the procedures and materials described herein. It is the responsibility of the user of this manual to obtain the appropriate material safety data sheets (MSDS) and to establish appropriate safety and health practices to determine the applicability of regulatory limitations prior to use.

bituminous and portland cement concrete pave-ment is an effective method of extending pavement life and reducing the need for extensive repair work. When sealing is performed at the proper time, using the appropriate materials and proce-dures, life-cycle costs of the pavement structure can be reduced. One of the major factors in achieving optimum pavement performance is to properly seal and maintain joints and cracks.

When incorrect procedures or poor quality materi-als are employed, major costs may result. Improp-er procedures can in fact accelerate other forms of pavement deterioration. This manual provides guidance on the evaluation of existing sealant condition, criteria for replacing sealants, data on selecting sealant materials, sealant installation procedures, and guidelines for inspection during and after the sealing operation.

2-1

CHAPTER 2

SEALANT MATERIALS

2-1. General. This chapter provides guidance cause the affected slabs to crack.

for the selection of sealants, the functions of each (4) In bituminous pavement, the heaving of sealant, and the background needed to understand the pavement at the cracks due to frozen moisture sealant performance and quality control required results in increased surface roughness. The satu-to produce a sealing project with satisfactory per- rated base or subbase material allows high deflec-formance. Appendix B provides comparisons be- tions under wheel loading which causes additional tween American Society for Testing and Materials cracking of the pavement.

(ASTM) and Federal Specifications (FS). b. The second function of the sealant is to

2-2. Sealant Functions. joint or crack. There are several pavement dis-

a. There are two primary functions of joint and tresses associated with the retention of incom-crack sealants. The first is to prevent surface pressibles in joints and cracks. When the pave-water from seeping through the pavement struc- ment contracts during low temperatures, the joints ture into underlying water susceptible soils or base and cracks open, allowing incompressible materi-courses, and the second is to prevent the retention als to fill the available space. As the temperature of incompressibles in the joint or crack. Both of increases, the pavement expands, However, the these functions are extremely important in expansion is restricted by the incompressibles that preventing premature pavement failure by main- have filled the joint and crack openings. In con-taining pavement durability and structural integ- crete pavement, the restricted movement causes rity. A discussion of each function is given on the spalling, and, in severe cases, blowups. In bitumi-following pages. nous pavement, it causes upward tenting at the

(1) Water seepage must be prevented from cracks. On airfield pavement, the retention of entering into water susceptible soils such as those debris and incompressibles in joints create a with a high fines content or a high plasticity index potential for FOD to aircraft.

(PI). If water is allowed to penetrate into the water susceptible soil foundation of a pavement, 2-3. Sealant Types.

the increased moisture content leads to a decrease a. The three types of sealant materials used in soil strength. For portland cement concrete when sealing or resealing joints are field-poured (PCC) pavement, the water seepage reduces the (field molded) hot-applied, field-poured (field subgrade support which may lead to pumping, molded) cold-applied, and preformed elastomeric corner breaks, shattered slabs, and other load seals. The type of sealant that should be used for associated distresses. For bituminous pavement, a a project is determined from several reduction in foundation strength produces the considerations including the type of pavement, appearance of alligator or fatigue cracking. joint design, joint or crack condition,

(2) Water infiltration into PCC can also environment, cost, and the use of the pavement lead to the loss of durability. The progressive loss section in question. A typical joint which indicates of durability, commonly called "D-cracking," is a the appropriate terminology used in discussing a moisture-freeze-thaw aggregate interaction that joint is shown in figure 2-1.

destroys the structure of the concrete. This type of b. Field-poured sealant materials are liquid at deterioration is often found where low-quality car- the time of application and solidify by either bonate rocks are used as concrete aggregate and is cooling or by a physical or chemical reaction. The common where moisture and temperature condi- hot-applied sealants which solidify by cooling are tions produce the moisture-freeze-thaw cycles nec- referred to as thermoplastic type materials. Hot-essary for deterioration. The weakening of the applied sealants that react when heated to solidify concrete around joints and cracks leads to poten- are referred to as thermosetting materials. The tial spalling of the concrete, increased roughness, cold-applied sealants solidify by a chemical reac-and increased foreign object damage (FOD). tion between two components or a physical reac-

(3) The seepage water may also contain tion, such as solvent evaporation. Sealants may be deicing salts or chemicals that cause load further classified as either jet-fuel resistant (JFR) transferring steel dowels to corrode. The corroded or non-JFR. JFR sealants are normally a tar based dowels lock up and prevent the slabs from moving material while non-JFR sealants are normally in response to temperature changes which in turn asphalt based materials. The base material for the prevent the retention of incompressibles in the

2-2 two classifications is combined with rubber rubber down to low-grade waste, such as buffings materials or polymers that have rubber-like from tire retreading operations. Because of this properties to improve performance characteristics. variation, the quality of the sealants also vary The hot-applied sealants in PCC pavements may widely. Federal Specification SS-S-1401C, ASTM cause problems associated with bubbling or the D 3405, and ASTM D 1190 cover field-poured creation of voids in the sealant. hot-applied rubberized asphalt sealants. Federal

(1) The non-JFR rubberized-asphalt sealant Specification SS-S-1401C, ASTM D 3405, and is the most widely used of all joint sealant ASTM D 1190 can be used in bituminous materials in both bituminous and PCC pavements pavements, but for PCC pavements Federal and is used for highways, streets, and taxiways. Specification SS-S-1401C is usually specified.

The material is made by dispersing a rubber Asphalt based sealants should not be used in areas material or a rubberlike polymer in a suitable where fuel or lubricant spillage is expected grade of asphalt cement. The rubber materials because the spilled materials are usually petroleum vary from new rubber and high-quality reclaimed derivatives. Petroleum derivatives have a solvent

2-3 reaction with asphalt, which is also derived from (c) During the storage of two component petroleum. sealants, the accelerating agent, typically a powder

(2) JFR sealants are usually made from a tar in suspension, can settle to the bottom of the based material modified with suitable resins or sealant container. The settlement can be mini-polymers. These sealants are most widely used on mized by turning the containers upside down at PCC pavement subjected to fuel spillage or lubri- regular intervals, such as 1-week intervals. Even cant leaks. JFR sealants should be used for park- when this procedure is followed, the accelerator ing aprons, maintenance areas, and refueling ar- should be thoroughly remixed before being placed eas. Most tar is produced from coal which gives it in the application equipment. The mixing can be a different chemical makeup than asphalt, render- accomplished using any suitable hand held device, ing the tar based sealant less affected by the such as a drill equipped with a mixing paddle, that spillage of petroleum based materials. Federal mixes horizontally and vertically to ensure the Specification SS-S-1614A covers field-poured hot- curing agent is lifted off of the bottom of the applied JFR sealants. These sealants may be container and resuspended into the liquid.

damaged by synthetic hydraulic fluids.

c. Field-Poured Cold Applied Sealants.

(1) Two-component polymer type cold-applied JFR sealants used in PCC pavements are covered in Federal Specification SS-S-200E, under Type H or Type M. These polymer-type sealants are tar, polyurethane, or polysulfide based materials modified with suitable elastomeric polymers or resins. One of the two components contains the polymer in liquid form, and the other component contains the chemical that solidifies the polymer. These sealants are used in areas that are subjected to fuel spillage and jet blast. Although the sealant is not completely jet blast resistant, it is more resistant to the heat from jet blast than the sealants in Federal Specification SS-S-1614A.

Some one-component materials are being produced that claim to meet the performance requirements of Federal Specification SS-S-200E.

The sealant material must be tested to ensure specification conformance before its use is approved.

(a) Federal Specification SS-S-200E, Type H. Type H two-component sealants are designed for hand-mixing. Type H sealants are generally used for small projects and spot repairs of deterio-rated sealant in areas where fuel spillage and/or heat blast are expected. Type H sealants are normally not used for major sealing projects; how-ever, some Type H sealants are manufactured for areas that are on steep inclines such as embank-ment areas. The steep slopes would make it diffi-cult to use sealant application equipment, and therefore, a hand-mix sealant would be desirable.

(b) Federal Specification SS-S-200E, Type M. Type M two-component sealants are designed to be machine-mixed in a one-to-one ratio by volume using the appropriate sealant mixing/application equipment described later.

Machine-mixed sealants are normally used for large sealing projects in areas where fuel spillage and/or heat blast are expected.

(2) Single component non-JFR cold applied sealants, such as silicone and nitrile rubber based materials can be used in both bituminous and PCC pavements not subjected to fuel spillage unless they are specifically tested for fuel resistance.

d. Preformed elastomeric (compression) seals are solid at the time of installation and therefore must be sized for a given joint. Not all preformed seals are fuel resistant; therefore, their use in areas where fuel spillage is expected must be restricted to only those fabricated from fuel resistant materials.

e. Preformed elastomeric compression seals have been made of bituminous-impregnated foam rubber, cork, or extruded polychloroprene. The polychloroprene seal is used more often than the others and is a labyrinth or webbed type seal referred to as the elastomeric compression seal.

ASTM D 2628 is the specification used in selecting appropriate seals. A lubricant/adhesive is required when installing the preformed seal into the joint. The lubricant coats the seal to allow easier installation of the seal. Once the seal is in place, solvent evaporates from the lubricant and it becomes a very weak adhesive. The specification requirements for the lubricant/adhesive are given in ASTM D 2835. Since the preformed seals must remain in compression in the joint at all times to function properly, it is necessary to properly size the seal. Guidance for sizing preformed compres-sion seals is provided in appendix C. Some pre-formed seals are not compression seals. Instead, they are applied in the joint with an adhesive which maintains the seal's bond with the concrete.

The selected width of the noncompression seal is equal to the width of the joint. The adhesive is applied to the joint faces and to the seal. The seal is inserted into the joint and pressurized until the adhesive cures. The adhesive used for this type of seal is much stronger than the ones which conform to ASTM D 2835.

2-4

f. Some joint sealing projects may require that manufacturers recommend a primer to be used to a sealant be compatible with liquid oxygen (LOX), improve the sealant's bond to concrete. If a for example LOX storage areas. Sealants that are primer is recommended, it should be used during not LOX compatible could possibly create an the acceptance testing and must be applied to the explosion when they come in contact with LOX. joints in the field. Full compliance with material Some sealants are more resistant to LOX than specification test requirements does not guarantee others; therefore, the major command engineer the desired sealant performance in the field. The must be consulted to determine if a sealant is requirements involving joint and crack preparation acceptable before using any sealant material in a and sealant installation play a significant role in LOX area. In new construction projects, LOX sealant field performance. Poor workmanship will areas should be designed using continually result in poor sealant field performance regardless reinforced concrete. of the quality of the sealant material. Laboratory

g. Fillers. Joint and crack fillers are materials tests only indicate the expected relative behavior that are used to fill joints and cracks, but the of sealants that are properly installed.

material is not pliable or elastic enough to with- c. The series of tests conducted on each type of stand pavement movement. The most common sealant are provided in table 2-1. ASTM tests are types of fillers are emulsions, cutbacks, asphalt included in table 2-1 for reference between federal cements, asphalt or emulsion sand mixtures, and specifications and the ASTM specifications. The for large cracks, asphalt cement pavement mix- important features of the more critical tests are tures. Choosing which of these materials should be listed below.

used for the crack sealing project is based upon the expected future use of the pavement and the 2-5. Backer and Separating Material.

size of the cracks. If the pavement is to be a. Backer Material. The backer material, which overlaid within 2 years, then emulsion or sand is often termed "backer rod," provides support to emulsion mixture could be used. If the pavement the sealant material to prevent field-poured seal-is not expected to be overlaid or abandoned in the ants from sagging into joint reservoirs deeper than near future, a high-quality sealant should be used. the desired sealant depth. The backer material Some crumb rubber modified asphalt formulations provides the proper shape factor for the sealant have worked very well as crack sealants; however, and prevents bonding between the new sealant and they may not meet current federal specifications. any old sealant remaining in the lower portion of Therefore, their use should be thoroughly investi- the joint reservoir or between the sealant and the gated and approval obtained before they are in- lower portion of the joint reservoir, which is stalled in the pavement. known as three-sided adhesion. The backer

h. To perform properly, the sealant must prevent material must be flexible, compressible, non-intrusion of water and incompressibles. To accom- shrinkable, nonreactive, and nonmoisture absorp-plish this, the sealant must bond to the pavement, tive material such as a closed-cell remain resilient, and reject incompressibles. It polychloroprene, polyurethane, polystyrene or should not harden, crack, split, or separate from polyethylene rod. Paper rods, ropes, or cords and the joint or crack faces. Tests used to evaluate some open-cell foam rods should not be used these properties are presented in the following because of the amount of water they can absorb.

section. Normally fillers do not possess sealing The absorption of the backer material should be abilities which would allow them to fulfill these tested if there is any doubt. The backer material requirements. should have a melting temperature of at least 5

2-4. Sealant Properties. temperature of the sealant. The uncompressed backer material should be approximately 25a. The sealant must be resistant to aging or ultraviolet deterioration, which is evident by a hardening of the sealant or loss of resiliency.

Additional properties such as jet ("eat) blast resis-tance or fuel resistance are related to specific conditions that the sealant will encounter.

b. The properties of a sealant are indicated by the tests that are required for specification compli-ance. Different tests are required of different sealant types to emphasize the particular properties each sealant should possess. Some sealant degrees Fahrenheit higher than the pouring percent wider in diameter than the nominal width of the joint to keep it in position during the installation of the sealant. Different types of backer rod materials are illustrated in figure 2-2.

b. Separating Material. When the joint seal res-ervoir is sawed or formed to the desired sealant depth, a separating material should be used be-neath the sealant. The separating material pre-vents field-poured sealants from bonding to the bottom of the reservoir or contacting any old

2-5

2-6 sealant or filler in the lower portion of the joint or cold applied, depends in part upon the joint reservoir. Separating materials are typically adhe- size, shape, and cleanliness for good performance.

sive backed tapes or low strength plastic strips. These sealants rely on a strong bond forming The material must be low strength to deform with between the sealant and the joint sidewalls or the sealant as the pavement moves. These materi- faces. As the joint opens or closes under the als should have a melting point at least 5 degrees effects of daily temperature changes, the sealant is Fahrenheit higher than the pouring temperature of stretched or compressed. An adequate bond is the sealant and should be approximately 1/8 inch necessary to prevent the sealant from pulling away wider than the nominal width of the joint from the joint face or being forced out of the joint reservoir. The additional width will help the sepa- during these movements. Figure 2-4 illustrates the rating material stay in position as the sealant is stresses a field-poured sealant undergoes as the being installed, and will prevent the separating joint opens and closes. A brief description of the material from floating up into the sealant. The stresses which develop are as follows:

separating material should be flexible and non- (1) Adhesive stress is the bond stress between reactive with the sealant in the same manner as the the sealant and joint face caused by tension as the backer material. If there is any doubt about the joint expands. The sealant will separate from the compatibility of the separating material or the joint face if the bond strength is too weak or the backer material and the sealant, a trial joint may tensile stress created by the movement is too be sealed during the equipment evaluation to large.

ensure the material will perform as desired. Fig- (2) Cohesive stress results from the tensile ure 2-3 illustrates the function of the separating load within the sealant material itself. The sealant and backer materials. will split under this stress if the sealant is not

2-6. Shape Factor. the sealant is too weak.

(3) Peeling stress results from load concentra-

a. The performance of field-poured sealants, hot sufficiently elastic or the interparticle bond within tion at the edge of the contact surface between the

2-7 sealant and the joint face. The sealant peels away bond between the compression seal and the joint is from the joint face leading to a loss of bond. provided by the use of a lubricant/adhesive during Excessive movement of the joint, horizontal or installation of the preformed seal. The lubricant/ vertical, may produce this stress. adhesive acts as a lubricant during installation of

(4) Tensile stress on the joint face material is the seal and then cures to become a weak adhe-the tensile stress between the sealant and face of sive. The adhesive is easily damaged if the joint the joint reservoir. When the joint faces have not opens wider than the seal. If the joint does open been properly cleaned or when the concrete is wider than the seal, the compressive force will be weak, deteriorated, or damaged during joint lost, and the seal will either fall down into the preparation, the sealant will pull the weaker joint or be pulled out by traffic. It is very critical material apart as the joint opens. that the correct seal size be selected and that the

(5) Compressive stress is the stress occurring seal maintains its elastic properties. The proce-in the sealant when the joint closes. When under dural guide for selecting the proper seal size is excessive stress, the sealant may be pushed above given in appendix C. Figure 2-5 illustrates the the pavement surface and tracked onto the pave- stresses that develop the preformed compression ment or abraded by traffic, or enough of the seal as the joint opens and closes. A brief descrip-sealant may be pushed above the pavement surface tion of the stresses are as follows:

so that the sealant is pulled completely out of the (1) The seal remains in compression by trans-joint reservoir. mitting forces to the joint face through compres-

b. The preformed compression seals rely more sion of the webs, which act similar to springs.

heavily on the joint size, shape, and condition for This is known as the web stress of a seal.

good performance than do the field-poured seal- Compression set is when the joint becomes too ants. Compression seals must remain in compres- narrow and the compression stress becomes too sion even when the joint is open to its maximum large causing the webs to lose their elasticity. As width. This is necessary to maintain the contact a result, the webs are no longer able to transmit pressure required between the seal and the joint the required force to the joint face as the joint face to hold the seal in place. There is essentially opens. When compression set occurs, the seal no bond between the compression seal and the either falls to the bottom of the joint or is pulled joint faces except as provided by the friction out when the joint reopens.

induced by compressive forces. Only a very weak

2-8

(2) Improper web design can produce a To maintain adequate adhesion and to reduce the vertical component to the web stress which is internal strains of a sealant, a shape factor known as vertical stress. If this stress is not between 1.0 and 1.5 is recommended (1.0#S#1.5, balanced, the seal can work itself out of or deeper where S = DJW) for most field-poured sealants.

into the joint as the joint opens and closes. Some single-component cold-applied sealants

c. As joints open and close, field.poured require a shape factor of less than 1 to perform sealants change in shape but not in volume. properly; therefore, particular care in designing Therefore, the stresses that occur are primarily a the joints and selecting the depth to install backer function of the shape of the sealant at the time it is material should be taken when these materials are poured. The shape of the field-poured sealant is used. The shape factor of the preformed expressed in terms of the depth (D) to width (W) compression seal is determined by the ratio as shown in figure 2-1. The depth to width manufacturer.

ratio (DJW) is known as the shape factor. d. The depth of a field-poured sealant can be Providing a small shape factor, small depth versus controlled by the use of a backer material if the a large width for an in-place sealant generally joint reservoir depth is deeper than the depth reduces the internal strains, hence improving the required to maintain the proper shape factor. The elasticity of the field-poured sealant. However, a backer material helps support the sealant during relatively large sealant depth is desirable to ensure curing and prevents sagging of the sealant into the adequate bonding of the sealant to the joint face. lower portion of the joint. The backer material

2-9 should not bond with the sealant. If the sealant and result in loss of bond between the sealant and adheres to a stiff backer material, the sealant will joint or crack face, internal rupture of the sealant, not be as free to move at the bottom as it is at the extrusion of the sealant from the joint or crack, top. This causes higher stresses in the sealant and and intrusion of debris into the sealant. Defects can lead to premature failure of the sealant. can be reduced or eliminated by one or more of Therefore, the backer material should be as soft the following:

and flexible as possible, but stiff enough to stay in (1) Reduce the strains in the sealant by using position in the joint to maintain the correct shape better shape factors either by sawing or forming factor. Backer materials that absorb water and the joint reservoir to the proper size and shape.

expand must not be used, since the moisture can (2) Use the proper backer materials to damage the effectiveness of the sealant. support the sealant and prevent sagging, provide along the bottom of the joint to prevent three-sided2-7. Common Sealant Defects.

a. Field-Poured Sealants. Figure 2-6 illustrates (3) Reduce movement at the joints by using common sealant defects in field-poured sealants shorter joint spacings.

and lists some of their possible causes. The defects (4) Ensure joint and crack faces are properly result from excessive stresses as discussed earlier cleaned before sealing.

a suitable shape factor, and provide a weak bond adhesion.

2-10

(5) Select a sealant that resists intrusion of b. Preformed Compression Seals. Figure 2-7 il-debris. lustrates common defects and lists their possible

(6) Select a sealant that resists hardening or causes for preformed compression seals. The de-oxidizing and remains elastic. fects include slip down, twisting, extrusion, and

(7) Ensure the sealant conforms to the appro- compression set of the seal. The defects can be priate specification by having it tested by an reduced or eliminated as follows:

independent laboratory. (1) Size the seals properly (see app C).

(8) Remove debris from the surface of the (2) Use seals with characteristics that provide pavement as much as possible. better low temperature recovery and resistance to

(9) Avoid trapping air and moisture in the permanent set at high temperatures.

sealant during installation. (3) Use care during installation and use the

(10) Recess the sealant below the pavement manufacturer's recommended installation equipment.

surface.

2-11

(4) In new construction, specify joint widths before placing the seal. Preformed compression of 1/2 inch minimum and 5/8 inch maximum, seals are not generally used for resealing projects setting the joint spacing accordingly. TM 5-825- because of irregularities in the shape of the joint.

3/AFM 88-6, chapter 3, gives appropriate joint When using preformed compression seals, the spacings. joint faces must be vertical and uniform.

(5) In resealing operations, repair all spalls

3-1

CHAPTER 3

DETERMINING SEALING NEEDS

3-1. General. The information provided in (5) Splitting of the sealant material or cohe-this chapter can be used to help determine the sion failure.

sealing requirements of an existing pavement. TM (6) Lack or absence of sealant in the joint.

5-826-6/AFR 93-5 provides definitions of terms (7) Sealant placed too low in the joint.

used in pavement evaluation. The steps to deter- (8) Uncured sealant.

mine if a pavement should be resealed and the c. Severity Levels. The description of severity sealant and procedures that are used in resealing levels listed below are discussed in TM 5-826-are explained in the following paragraphs. 6/AFR 93-5 and are given in general terms below

3-2. Factors to be Considered. There are types of joint seal damage were previously pre-many factors that should be considered when sented in figures 2-6 and 2-7.

answering the "to seal or not to seal" question. (1) Low Severity. The joint sealant is Once this question has been answered, there are generally in good condition throughout the other factors that need to be considered in select- section. The sealant is performing well with only ing the best sealant and the proper installation a minor amount of any of the above types of procedures for a project. A brief discussion of damage present. For individual joints being each factor is presented in the general order in examined, low severity is when the sealant is in-which they should be considered. The relative place, but has no incompressible material intrusion importance of these factors will vary from site to and little loss of bond, cracking, splitting, or slip site and from feature to feature. down that would allow water infiltration. No other distresses have occurred.a. Purpose of a Sealant. A sealant which must prevent both water infiltration and incompressible intrusion must be in better condition than a sealant which is only required to prevent incompressible intrusion. If the pavement is in an area with high annual rainfall or has a moisture susceptible subgrade, the sealant is needed to minimize water intrusion. If the pavement is in an area with low annual rainfall or has a fast draining subbase, the sealant may be needed more to prevent intrusion of incompressibles.

b. Sealant Condition. The most important factor in evaluating pavement sealant requirements is the existing sealant condition. TM 5-826-6/AFR 93-5 defines joint seal damage as any condition that enables soil or rocks to accumulate in the joints or allows significant infiltration of water.

Accumulation of incompressible materials that prevent the slabs from expanding any may result in buckling, shattering, or spalling. A pliable joint sealant, bonded to the edges of the slabs, prevents the collection of incompressibles and the seepage of water into the joint weakening the foundation that is supporting the slab. Typical types of joint seal damage include:

(1) Extrusion of the joint sealant.

(2) Growth of vegetation in the joints.

(3) Hardening or oxidation of the sealant.

(4) Loss of bond between the sealant and pavement or adhesion failure.

for each sample unit and individual joints. The

(2) Medium Severity. The joint sealant is generally in fair condition over the entire surveyed section with one or more of the above types of damage occurring to a moderate degree. The seal-ant will need replacing within 2 years. For indi-vidual joints, the medium severity level has a small amount of debris retention or incompressible material intrusion, a moderate amount of extru-sion, twisting, slip down, cracking, splitting, or loss of resiliency has occurred.

(3) High Severity. The joint sealant is gener-ally in poor condition over the entire surveyed section with one or more of the above types of damage occurring to a severe degree. The sealant needs immediate replacement. High severity for individual joints means that some joint sealant is missing from the joint, a considerable amount of debris retention is present, and incompressible intrusion occurs which has caused spalling or allowed the free inflow of water.

(4) Joints with no Defects. If none of the listed damage types have occurred, the sample unit is not rated as having a severity level which means that the joint and sealant are in excellent condi-tion.

d. Variation of Sealant Condition. The sealant condition may vary throughout the pavement fea-ture. This will be noted by variance in the joint seal condition for the sample units in the pavement feature. This variance is important in deter-

3-2 mining whether routine sealing by in-house main- maintenance and repair needs of a pavement. If tenance personnel will suffice. the PCI is 40 to 60 or lower, the pavement has

e. Joint and Crack Condition. The condition of deteriorated to the point where it may need major the joint or crack affects how the sealant will repair in the near future. Resealing should always perform in the future and also indicates the be included as part of any major repair work. PCI relative need for joint repair before sealing. Sev- prediction programs available in PAVER and eral distress types such as spalling, faulting, set- Micro-PAVER should be used to determine if tlement or heave, corner spalls, and keyway fail- resealing the joints will raise the PCI of the ure may have to be repaired before effectively pavement feature enough to justify the cost deter-resealing the joint or crack. In extreme cases, it mined from a life-cycle cost analysis (see app D).

may be necessary to completely rebuild the joint h. Joint and Slab Design. The joint sealant before it can be successfully sealed. For example, reservoir and the pavement slab size must be joints with keyway failures or spalling require the considered when resealing, especially in selecting failure to be repaired before it is resealed. The the type of sealant and determining the amount of repair will reduce the potential for FOD and preparation required before resealing. The amount reduce the susceptibility of debris retention in the of horizontal movement at a joint (the working joint. The incompressible materials and debris in range of the joint) depends upon several factors a joint create nonuniform, high-compressive such as the size of the slab, the seasonal tempera-stresses on the joint faces as the joint tries to ture changes, friction between the slab and under-close. The compressive stresses can cause spalls, lying material, and the type of joint (transverse or blowups, or slab shoving. Joints that have only longitudinal). Therefore, longer slabs and greater minor spalling or widening due to intrusion of seasonal temperature changes cause more horizon-incompressibles require only cleaning and then tal joint movement. The working range of the resealing. The joint condition also influences the sealant, which is controlled by the sealant proper-selection of the sealant to be used when resealing. ties and the width of the joint reservoir, must be A liquid (field- poured) sealant can perform larger than the working range of the joint. A satisfactorily in a joint that has small spalls or sealant is more likely to fail in a narrow joint other joint shape irregularities while a preformed sealant reservoir than a wider one as described in compression seal cannot. The difference in chapter 2. It may be necessary to widen a joint performance results from the method each seal sealant reservoir before resealing to obtain ade-uses to bond with the joint faces. The preformed quate width and depth for satisfactory sealant compression seal must have a uniform joint shape. performance. Appendix C provides the working Otherwise, uneven pressures will be placed on the range calculations for joints and sealants.

seal and force it out of the joint (see fig 2-5), and i. Current and Future Mission of the Pavement a field-poured sealant will take the shape of the Feature. The type of traffic and pavement use existing joint. must be considered when determining the need to

f. Moisture Accelerated Distress Types. The reseal and the type of sealant to use. The amount infiltration of water through joints or cracks into of allowable FOD depends upon the type of a moisture susceptible subbase or subgrade can aircraft or other traffic using the pavement. The cause or accelerate moisture related distresses. In pavement use will determine the expected amount concrete pavement, the moisture related distresses of fuel, hydraulic, and other fluid spillages which may be indicated by pumping, corner breaks, the sealant must withstand. Any expected changes settlement or faulting, or cracking caused by in either type of traffic or pavement use may subgrade volume change. In bituminous pavement, require a different type of sealant to be used the moisture related distresses include medium- to instead of the type indicated by present conditions.

high-severity alligator cracking, depressions and j. Performance of Previous Sealant. Hot- and swells, and medium- to high-severity transverse cold-applied sealants meeting current specifica-and longitudinal cracking. If a significant amount tions should last 4 to 6 years, and preformed of these distress types occur, resealing should be elastomeric compression seals should last 10 to 15 done immediately before the distress develops in years. Some improved liquid sealants have lasted other areas of the pavement. The damaged pave- much longer than the 4- to 6-year time frame and ment area should be removed and replaced to some have failed in less than 1 year. The age of maintain the load-carrying capability of the pave- the existing sealant should be determined, and if it ment. failed rapidly, the cause of deterioration should be

g. Overall Pavement Condition. The pavement determined. If possible, the cause of deterioration surface condition is measured using the pavement should be eliminated before resealing. Failure to condition index (PCI). It is directly related to the remedy the problem will probably cause the new

3-3 sealant to fail prematurely in the same manner as table 3-1, to show the overall condition of the the previous sealant. Examples of possible causes joint sealant. The relative amounts of each level of of premature sealant failure may include but are severity present can be recorded to show the not limited to incorrect sealant reservoir shape variability of the joint seal damage.

factors, excessive vertical movement or too large c. Determine Joint or Crack Condition. The of a working range at the joint, and improper condition of the joints or cracks is recorded as the sealing techniques used during sealant installation. percentage of slabs with the specified severity of

3-3. Condition Survey. to determine the existing pavement condition. The

a. The pavement must be surveyed according to general condition of the pavement feature being the procedures in TM 5-826-6/AFR 93-5 to deter- evaluated and the secondary factors of environ-mine the current condition of the sealant, the joint ment and soil type which influence joint sealant and crack condition, moisture related distress performance must be recorded. The data provide types, and the overall pavement condition. Field the information needed to evaluate sealant needs measurements may be required to determine the and function. Historical data and future use are existing joint shape factor. The measurements recorded to provide an indication of past perfor-should be made during the condition survey by mance and future requirements of the sealant and physically removing some of the old sealant and feature. The data collected can be presented on the recording its shape and hardness. Tables 3-1 and pavement evaluation checklist shown in table 3-2.

3-2 contain the items that should be collected to allow evaluation of the sealant and pavement. 3-4. Evaluation to Justify Sealing

b. Determining…