1、UFC 3-270-02 15 March 2001 UNIFIED FACILITIES CRITERIA (UFC) ASPHALT CRACK REPAIR APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-UFC 3-270-02 15 March 2001 UNIFIED FACILITIES CRITERIA (UFC) ASPHALT
2、 CRACK REPAIR 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
3、ENGINEER SUPPORT AGENCY Record of Changes (changes are indicated by 1 . /1/) Change No. Date Location 1 16 May 2006 Revised Foreword The format of this document does not conform to UFC 1-300-1; however, it will be reformatted at the next major revision. 1Provided by IHSNot for ResaleNo reproduction
4、or networking permitted without license from IHS-,-,-UFC 3-270-02 15 March 2001 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 Departm
5、ents, the Defense Agencies, and the DoD Field Activities in accordance with USD(AThowever, letter surveys of State DOTs have indicated that Fed. Spec. SS-S-1401C and ASTM D3405 sealants generally perform better in cooler regions than do ASTM D 1190 sealants. It isrecommended that ASTM D 1190 materia
6、ls not be used in areas that receive a high volume ofpedestrian traffic due to the materials tendency to track onto the pavement and stick to the solesof shoes.5.2. DOT Spec. Rubberized asphalt sealants that are not covered by the above specificationscan be used only when an appropriate State DOT or
7、 local municipality material specification isavailable and after the sealant has been approved by the Facilities Engineer. The DOT and localspecifications will often be modified to account for the temperature variations of the region.Asphalt cements that contain synthetic fibers have been used succe
8、ssfully on a limited basis as acrack sealant. State or municipality specifications should also be used for these materials.5.3. Other. The crack sealant material should be tested by a government-approved independentlaboratory for specification conformance before it is used on a project. If the quant
9、ity of sealantfor the project is less than 500 pounds (227 kilograms), then the manufacturers certificate ofcompliance may be accepted in place of testing. The evaluation of local field performance datafrom past sealing projects is often helpful in determining which type of sealant should be used to
10、seal the cracks.9UFC 3-270-0215 March 20015Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-CHAPTER 6CRACK PREPARATION EQUIPMENT6.1. Introduction. The eq
11、uipment used to prepare a crack for sealing will depend on the size ofthe crack. Equipment used to prepare a crack will be discussed in this chapter, and theprocedures for using the equipment will be discussed in Chapter 7.6.2. Equipment Inspection. All crack preparation equipment should be inspecte
12、d before andduring actual construction. Inspection will determine if the equipment is being properlymaintained, if all of the required safety devices are present, if the equipment is damaging thepavement, and if the equipment is being operated correctly and safely.6.3. Equipment. Crack preparation e
13、quipment includes the following:6.3.1. Router. A router is used to create a sealant reservoir by enlarging meandering cracks tothe desired depth and width. A vertical spindle router with a diamond bit (Figure 6.1.) isrecommended to minimize damage to the asphalt pavement; however, an impact router(F
14、igures 6.2. and 6.3.) may be used if it is equipped with carbide-tipped vertical-sided bits.Impact routers that are not equipped with carbide-tipped bits or those equipped with V-shapedbits should not be used because they tend to chip and damage the asphalt pavement. Whenusing a vertical spindle rou
15、ter, the router bit should be belt-driven to help prevent injury to theoperator and damage to the pavement if the bit jams in the crack. If damage to the pavement isobserved, work should be discontinued until corrective action is taken. Such corrective actionmay require replacing worn router bits, c
16、hanging operators, or replacing the equipmentcompletely.6.3.2. Concrete saw. A concrete saw with a water-cooled diamond blade or abrasive disk canbe used to widen straight cracks to the desired width and depth. Concrete saws may be used in116UFC 3-270-0215 March 2001Provided by IHSNot for ResaleNo r
17、eproduction or networking permitted without license from IHS-,-,-place of a router if the blade has a diameter of 6 inches (150 millimeters) or less (Figure 6.4.).The 6-inch- (150-millimeter-) diameter blade allows the saw to follow slightly meandering cracks;however, a saw blade does not follow the
18、 meandering crack as well as a router. If a saw is usedto widen the crack, a high-pressure water stream can be used to remove the debris created bythe saw (Figure 6.5.).6.3.3. Hot compressed-air (HCA) heat lance. The HCA heat lance (Figure 6.6.) is used to warm,dry, and clean the crack when the seal
19、ing operation must be conducted in less than desirableconditions. Such conditions occur following rain or when the pavement temperature is below50 degrees Fahrenheit (10 degrees Celsius). The heat lance can also be used to remove smallamounts of vegetation from cracks. Heat lances are capable of pro
20、ducing heated air at3,000 degrees Fahrenheit (1,650 degrees Celsius) at velocities of up to 3,000 feet per second(915 meters per second); therefore, extreme care must be used by the operator. The heat lanceshould not remain stationary over one spot but should be kept moving to ensure that the asphal
21、tpavement is not overheated. Overheating will cause the pavement to become charred and brittle,resulting in premature sealant bond failure. Heating the cracks using direct flame methodsshould not be permitted. Direct flames harden the asphalt and leave a sooty residue thatprevents adequate bonding o
22、f the sealant to the asphalt pavement.6.3.4. Sandblasting equipment. Sandblasting equipment (Figure 6.7.) is used to remove residueleft by the saw, loosened aggregate left by the router, vegetation, and other debris. If debris isleft in the crack, the sealant will not bond adequately to the asphalt,
23、 causing premature failure.Equipment for sandblasting consists of an air compressor, hoses, and a venturi-type nozzle withan opening not to exceed 1/4 inch (6 millimeters). The air compressor should be equipped withtraps that will keep the compressed air free of oil and moisture. The compressor shou
24、ld becapable of supplying air at 150 cubic feet per second (4 cubic meters per second) andmaintaining a line pressure of 90 pounds per square inch (620 kilopascals). Caution should be12UFC 3-270-0215 March 2001Provided by IHSNot for ResaleNo reproduction or networking permitted without license from
25、IHS-,-,-exercised to prevent overblasting the crack. It is important to remove all debris from the crack,but overblasting could cause the pavement to ravel or create voids in the crack face.6.3.5. Wire brushes. Wire brushes (Figure 6.8.) are helpful in removing debris and vegetationfrom shallow crac
26、ks, but they do not easily remove debris, such as saw residue, from the walls ofthe cracks. Debris on the crack faces will cause the sealant to lose adhesion with the pavementand prematurely fail. Worn brushes should not be used to clean the cracks because they will noteffectively remove residual de
27、bris. Care should also be taken when wire brushes are used toclean cracks that have been sealed before. The brushes will have a tendency to smear the oldsealant residue on the crack wall instead of removing it.6.3.6. Hand tools. When approved by the Contracting Officer, hand tools may be used forrep
28、airing or cleaning cracks or removing old crack sealant. The tools should be examined toensure that they will not damage the pavement in any manner when properly used.13UFC 3-270-0215 March 20016Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-14Figur
29、e 6.1. Vertical spindle router Figure 6.2. Rotary impact routerUFC 3-270-0215 March 2001Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-15Figure 6.3. Carbide-tipped rotary impact router bit Figure 6.4. Concrete saw with a 6-in.- (150-mm-)diameter bla
30、de6UFC 3-270-0215 March 2001Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-16Figure 6.5. High-pressure water cleaningequipmentFigure 6.6. Hot compressed-air heat lanceUFC 3-270-0215 March 2001Provided by IHSNot for ResaleNo reproduction or networkin
31、g permitted without license from IHS-,-,-17Figure 6.7. Sandblasting equipment Figure 6.8. Wire brush equipment6UFC 3-270-0215 March 2001Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitt
32、ed without license from IHS-,-,-CHAPTER 7CRACK PREPARATION PROCEDURES7.1. Crack Size Guidelines. Crack preparation procedures depend on crack size. The followinginformation should be used as a guide when preparing cracks for sealing.7.1.1. Hairline cracks (less than 1/4 inch (6 millimeters). Hairlin
33、e cracks (Figure 7.1.) require nopreparation (see Chapter 9).7.1.2. Small cracks (1/4 to 3/4 inch (6 to 19 millimeters). Small cracks (Figure 7.2.) should bewidened to a nominal width of 1/8 inch (3 millimeters) greater than the existing nominal oraverage width. Widening the cracks 1/8 inch (3 milli
34、meters) will help eliminate the potential forraveling of the pavement along the edges of the crack and will provide a sealant reservoir thathas vertical faces. The depth of the routed crack should be approximately 3/4 inch(19 millimeters). A backer rod material (see Chapter 9) should be placed in cr
35、acks that have adepth greater than 3/4 inch (19 millimeters). Backer rod materials are not required in cracks thatare 3/4 inch (19 millimeters) deep.7.1.3. Medium cracks (3/4 to 2 inches (19 to 50 millimeters). Cracks that are 3/4 to 2 inches(19 to 50 millimeters) (Figure 7.3.) shall be prepared by
36、simply cleaning the crack using asandblaster, HCA heat lance, or wire brushes, and then cleaning with compressed air. The crackmust be inspected to ensure that it is clean and dry.7.1.4. Large cracks (greater than 2 inches (50 millimeters). Cracks wider than 2 inches(50 millimeters) (Figure 7.4.) sh
37、ould be prepared in the same manner as potholes. A saw shouldbe used to cut away damaged pavement to provide vertical faces. The area should then becleaned and filled instead of sealed (see Chapter 9).197UFC 3-270-0215 March 2001Provided by IHSNot for ResaleNo reproduction or networking permitted wi
38、thout license from IHS-,-,-7.1.5. Cracks to be overlayed. Cracks larger than 1/4 inch (6 millimeters) in pavements that areto be overlaid can be prepared by cleaning with the sandblaster, HCA heat lance, or wire brushesand then cleaning with compressed air. Some specifications do not require the sea
39、ling of cracksin pavements that are to be overlaid; instead, the cracks are sealed when they reflect through theoverlay and therefore require only air cleaning. Large cracks should be prepared as describedabove.7.2. Crack Widening. Meandering cracks should be widened using a router; whereas, thestra
40、ighter cracks can be widened using a saw with a small-diameter blade. When a saw is used,the crack should be cleaned with a high-pressure water stream or a sandblaster to remove debriscreated by the saw. The recommended procedure is to use a router since water would not berequired. When resealing, i
41、t is important to remove all of the old sealant that is in the crack. Afterthe crack has been widened or the existing sealant has been removed, the crack should becleaned to prevent any debris from contaminating the crack.7.3. Initial Crack Cleaning. Cleaning of the crack can be accomplished by usin
42、g thesandblasting equipment, the HCA heat lance, or wire brushes. Information relative to thisequipment is presented as follows:7.3.1. Sandblasting equipment. When the sandblasting equipment is used, a technique thatenables both faces of the crack to be sandblasted should be established. A multiple-
43、passtechnique should be used which consists of positioning the sandblaster nozzle approximately1 inch (25 millimeters) above the pavement surface, sandblasting the entire length of one crackface, then sandblasting the entire length of the opposite crack face. Approximately 1 inch(25 millimeters) of
44、the pavement surface on both sides of the crack should also be sandblasted toremove debris. The cracks should not be overblasted. Overblasting can damage the pavement,causing raveling and premature bond failure of the sealant.20UFC 3-270-0215 March 2001Provided by IHSNot for ResaleNo reproduction or
45、 networking permitted without license from IHS-,-,-7.3.2. HCA heat lance. The HCA heat lance should only be used when the pavement is wetand/or cold (pavement temperature below 50 degrees Fahrenheit (10 degrees Celsius).Extreme care should be used to ensure the crack faces do not become overheated o
46、r burned.Overheating of the crack faces can greatly reduce the life expectancy of the sealant and adjacentpavement. The expected failures may be in the form of adhesion failure of the sealant oradditional cracking of the pavement between the area that was overheated and the remainder ofthe pavement.
47、7.3.3. Wire brushes. Wire brushes are commonly used during sealing projects; however, wirebrushes are not always capable of removing debris from the crack faces, and this debris cancause adhesion failures. Careful inspections should be conducted to ensure that the wirebrushes are not worn and that a
48、ll debris and dust have been removed.7.4. Debris Removal. The recommended procedure to remove debris from the crack is to routthe crack. This method normally removes the debris more effectively with less chance ofpavement damage. The rotary impact router equipped with carbide-tipped bits is generally fasterthan the spindle router. The precautions mentioned previously should always be observed.7.5. Final Crack Cleaning. Once the old sealant and debris have been removed from the c
