1、Standard Practice for Emulsified Asphalt Chip Seal Design AASHTO Designation: PP 82-16 (2018)1Technical Section: 5b, Bridge and Pavement Preservation Release: Group 1 (April) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C.
2、20001 TS-5b PP 82-1 AASHTO Standard Practice for Emulsified Asphalt Chip Seal Design AASHTO Designation: PP 82-16 (2018)1Technical Section: 5b, Bridge and Pavement Preservation Release: Group 1 (April) 1. SCOPE 1.1. This standard practice determines application quantities for applying aggregate chip
3、s and emulsified asphalt for chip seals. A chip seal is the application of emulsified asphalt, followed immediately by an application of a single layer of cover aggregate, with the option of including a fog seal to help with chip retention. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: MP 27, Mater
4、ials for Emulsified Asphalt Chip Seals T 19M/T 19, Bulk Density (“Unit Weight”) and Voids in Aggregate T 84, Specific Gravity and Absorption of Fine Aggregate T 85, Specific Gravity and Absorption of Coarse Aggregate 2.2. NCHRP Report: NCHRP Report 680, Manual for Emulsion-Based Chip Seals for Pavem
5、ent Preservation 3. TERMINOLOGY 3.1. Definitions: 3.1.1. badly pocked, porous, oxidizedsevere raveling of surface with much texture. 3.1.2. flushed-bleedingfree asphalt on the pavement surface with little or no texture. 3.1.3. slightly pocked, porous, oxidizedraveling beginning to show with moderate
6、 texture. 3.1.4. slightly porous, slightly oxidizedlittle or no free asphalt on the surface with noticeable but low texture. 3.1.5. smooth, non-poroussome free asphalt on the pavement surface, but with some texture. 2018 by the American Association of State Highway and Transportation Officials. All
7、rights reserved. Duplication is a violation of applicable law.TS-5b PP 82-2 AASHTO 4. SIGNIFICANCE AND USE 4.1. This standard practice may be used to determine the quantities of materials required for the construction of emulsified asphalt chip seals. 5. EMULSIFIED ASPHALT CHIP SEAL DESIGN REQUIREME
8、NTS 5.1. MaterialsEmulsified asphalt and aggregate used in the design should meet MP 27 and be representative of the materials used for the project. 5.1.1. Aggregate ChipsFabricate a board measuring 3 ft by 11/2ft. Three-quarter-in. thick particle board works well for this item. Attach 1-in. by 2-in
9、. pine wood strips to the edge of the board to create a raised edge. Weigh the completed board and record the weight in pounds. Place the chips to be used on the project on the board. The quantity will vary depending on the gradation, shape, and crushed content of the chips but should be no less tha
10、n 5 lb and no greater than 25 lb. Try to fit as many chips on the board within the confines of the edging as possible. The chips should not overlap each other and should be only one stone thick. Push the chips against the edge of the board. Place as many chips as possible onto the board until every
11、gap is filled. Reweigh the board containing the chips in pounds. Subtract the weight of the empty board from the weight of the board with chips. Multiply this value by 2. This is the quantity of chips to be used on the chip seal in pounds per square yard. Record this quantity as Q. 5.1.2. Emulsified
12、 AsphaltThe emulsified asphalt quantity is estimated by calculating the amount of asphalt needed to fill the voids between the chips to a specific embedment depth. That relationship is expressed as follows: 5.61 162.4Wed T VGAR += (1) where: A = emulsified asphalt quantity, gal/yd2; 5.61 = constant
13、for converting the units to gal/yd2e = percent embedment from Figure 1 expressed as a decimal; d = average mat depth, 1.33 Q/W; Q = quantity of chips from the board test, lb/yd2; W = dry loose unit weight of chips, pcf (see T 19M/T 19, Section 12 on shoveling); 62.4 = unit weight of water, pcf G = d
14、ry bulk specific gravity of chips (see T 84 and T 85); T = traffic correction factor from Table 1; V = pavement surface correction factor; and R = emulsified asphalt residue, expressed as a decimal, e. g., 0.65 = 65 percent. The result of the calculation for Equation 1 is the estimated emulsified as
15、phalt spray rate. Table 1Traffic Correction Factor, T Chip Seal Class I II III AADT 5000 Traffic Correction Factor, T 1.20 1.15 1.10 1.05 1.00 a aGreater than 5000 AADT has not been evaluated sufficiently to develop a recommended traffic correction factor. 2018 by the American Association of State H
16、ighway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-5b PP 82-3 AASHTO Figure 1Aggregate Embedment, percent, e (before Rolling) Table 2Substrate Surface Condition, V Existing Surface Condition Correction Factor, V, gal/yd2Flushed-bleedinga0.06 Smo
17、oth, non-porousa0.03 Slightly porous, slightly oxidized 0.00 Slightly pocked, porous, oxidizedb+0.03 Badly pocked, porous, oxidizedb+0.06 aA quantitative method using the Ball Penetration Test has also been reported in NCHRP Report 680. bA quantitative method using the Sand Patch Test has also been
18、reported in NCHRP Report 680. 5.1.3. Extra Chips to Avoid Roller Pick-UpMore aggregate should be spread during chip seal construction with emulsified asphalt than is actually needed to produce a one-stone layer. This extra material is applied to aid in reducing the potential for chips to be picked u
19、p by pneumatic rollers during construction. The amount of excess material will vary, but should be approximately 5 to 10 percent and never more than 10 percent. Adjustment up or down is necessary based on when the rollers begin to pick up the chips. 5.2. All design work will be carried out using agg
20、regate either directly from the job site stockpile or equivalent material from the same source and having substantially the same material properties. 6. REPORT 6.1. Report the aggregate spread rate, Q, in pounds per square yard to the nearest 1.0 lb/yd2. 6.2. Report the emulsified asphalt spray rate
21、, A, in gallons per square yard to the nearest 0.01 gal/yd2. 7. KEYWORDS 7.1. Aggregate; aggregate chips; chip seal; emulsified asphalt. 1This provisional standard was first published in 2016. Average Mat Depth, d, in.Aggregate Embedment,percent504540353025200.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.
