1、Standard Method of Test for Prediction of Asphalt-Bound Pavement Layer Temperatures AASHTO Designation: T 317-04 (2013)1American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-5a T 317-1 AASHTO Standard Method of Test for
2、Prediction of Asphalt-Bound Pavement Layer Temperatures AASHTO Designation: T 317-04 (2013)11. SCOPE 1.1. This test method provides a standard for measuring pavement surface temperature and predicting temperatures within the asphalt-bound layer(s) of a flexible pavement section. This test method pro
3、vides a means of estimating the temperature at depth from the pavement surface temperature, the time of day, the previous days high and low air temperatures, and the desired depth at which the temperature is to be estimated. 1.2. Deflection testing commonly involves the measurement of the pavement s
4、urface temperatures. This standard is based on temperature relationships developed as part of the Federal Highway Administration (FHWA) Long-Term Pavement Performance (LTPP) Seasonal Monitoring Program. 1.3. This test method is applicable for temperature predictions on flexible asphalt concrete (AC)
5、 and composite asphalt over portland cement concrete (AC/PCC) pavements. 1.4. This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the a
6、pplicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. Federal Highway Administration: Temperature Predictions and Adjustment Factors for Asphalt Pavements, Report Number FHWA-RD-98-085 Long-Term Pavement Performance Program Manual for Falling Weight Deflectometer Measurem
7、ents, Version 4.1, Report Number FHWA-HRT-06-132, 2006 3. TERMINOLOGY 3.1. Description of Terms Specific to This Standard: 3.1.1. BELLSan acronym based on the initials of the four developers of the method: Baltzer, Ertman-Larsen, Lukanen, and Stubstad. 3.1.2. depththe distance below the surface of t
8、he top layer of asphalt. 3.1.3. one-day air temperaturethe average of the minimum and maximum air temperatures at the location of testing for the previous 24-h day, C. 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of a
9、pplicable law.TS-5a T 317-2 AASHTO 4. SUMMARY OF TEST METHOD 4.1. Input Data Elements: 4.1.1. Infrared (IR) TemperatureThe exposed surface temperature of an asphalt pavement is measured, preferably with an infrared (IR) temperature-sensing device. 4.1.2. Time of DayThe time of day the temperature me
10、asurement takes place is recorded. 4.1.3. One-Day Air TemperatureThe average of the minimum and maximum air temperatures at the location of testing for the previous 24-h day, C. 4.1.4. Pavement DepthThe depth at which an estimate of the asphalt layer temperature that is required is specified. 4.2. T
11、he input data elements are entered into a regression formula that predicts the temperature within the asphalt pavement at depth. 5. SIGNIFICANCE AND USE 5.1. Analysis of deflection data from asphalt pavements almost always requires that the deflections or analysis results be adjusted for the effects
12、 of temperature. Measuring the temperature at depth requires that a hole be drilled into the pavement, partially filled with fluid, and the temperature measured with handheld devices. Alternatively, thermistors may be permanently installed at various locations. These processes are time consuming, re
13、sulting in a limited number of temperature measurements. 5.2. Current deflection testing equipment is often equipped with surface-temperaturesensing devices, for example, an infrared thermometer that measures the surface temperature at every test location. To adequately adjust the deflection or defl
14、ection results for the effects of temperature, the temperature at some depth must be known. 5.3. Utilization of this method results in a significant savings in time over the conventional practice of manually drilling holes into the pavement, and it results in a significant increase in the volume of
15、temperature data (one pavement temperature for each test point). 5.4. The BELLS temperature prediction model was based on temperature measurements made with surface temperature measurements between 0 and 40C during the unfrozen times of the year. Application of BELLS outside of those conditions is n
16、ot recommended. BELLS has been verified using the LTPP database at both mid-depth and third-depth temperature points. The use of BELLS to predict temperatures at depths shallower than the third point is not recommended. 6. APPARATUS 6.1. Surface Temperature Measurement Device: 6.1.1. The surface tem
17、perature measurement device can be an IR thermometer mounted on a deflection device, a handheld IR thermometer, or a surface contact thermometer. The temperature measurement device should be calibrated according to the manufacturers recommendations. Note 1The IR surface temperature is the most si gn
18、ificant variable in the BELLS regression equation presented in Section 7.1.1. Thus, it is important that users verify the calibration of the surface temperature measurement device in the application of the equation (FHWA-HRT-06-132). 2016 by the American Association of State Highway and Transportati
19、on Officials. All rights reserved. Duplication is a violation of applicable law.TS-5a T 317-3 AASHTO 7. CALCULATION 7.1. BELLS Method: 7.1.1. The BELLS method for production testing (called BELLS3 in other publications) has been derived based on temperature measurements taken on pavement surfaces th
20、at have been shaded for only a short time (less than 1 min). The following equation is valid for approximately 30 s of shading: Td= 0.95 + 0.892*IR + log (d) 1.250.448*IR + 0.621* (1-day) + 1.83*sin(hr18 15.5) + 0.042*IR*sin(hr18 13.5) (1) where: Td = pavement temperature at depth d, C; IR = infrare
21、d surface temperature, C; log = base 10 logarithm; d = depth at which asphalt temperature is to be predicted, mm; 1-day = the average of the minimum and maximum air temperatures at the location of testing for the previous 24-hour day, C; sin = sine function in 18-h clock system, with 2 radians equal
22、 to one 18-h cycle; hr18= time of day, in 24-h system, but calculated using an 18-h temperature rise and fall cycle, as indicated in Sections 7.1.1 and 7.1.2. 7.1.2. When using the sin (hr18 15.5) decimal time function, only use times from 11:00 to 05:00 h. If the actual time is not within this time
23、 range, then calculate the sine as if the time is 11:00 h (where the sin = 1). If the time is between midnight and 05:00 h, add 24 to the actual decimal time. Then calculate as follows: If the time is 13:15, then in decimal form, 13.25 15.50 = 2.25; 2.25/18 = 0.125; 0.125 2 = 0.785 radians; sin (0.7
24、85) = 0.707. Note that an 18-h sine function is assumed, with “flat” 1 sin segment between 05:00 and 11:00 h. Note 2BELLS has been verified using the LTPP database at both mid-depth and third-depth temperature points. Since almost no difference exists in the regressions derived from the data at eith
25、er depth, they were combined in deriving the BELLS equations (FHWA-RD-98-085). 7.2. Alternate Calculation Method: 7.2.1. Equation 1 can be calculated alternatively using degrees instead of radians and putting the sine function terms in a tabular form as shown below: Td= 0.95 + 0.892*IR + log(d) 1.25
26、*0.44*IR + 0.621*(1-day) + 1.83*A + 0.042*IR*B (2) where: A = dependent on time of day as in Table 1; B = dependent on time of day as in Table 1; and sin = sine functionbrackets contents ar e in degrees (360 degrees equal to one 18-h cycle). 2016 by the American Association of State Highway and Tran
27、sportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-5a T 317-4 AASHTO Table 1Values of A and B as Function of h Time of DayaA B 0.0 11 OR decimal.hrs 9 OR decimal.hrs 3 THEN IF decimal.hrs 3 THEN decimal.hrs = decimal.hrs + 24 sine13.5 = SIN(2 * pi * (decimal.h
28、rs 13.5)/18) ELSE sine13.5 = 1 END IF td = 0.95 + .892 * ir logdepth = LOG(d)/LOG(10) 1.25 firstbracket = 0.448 * ir + 0.621 * air + 1.83 * sine15.5 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-5a
29、 T 317-6 AASHTO last.term = 0.042 * ir * sine13.5 td = td + logdepth * firstbracket + last.term 1Minor editorial revisions have been made at the discretion of the authors responsible for standards on pavement measurement technologies (technical section 5a). 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.
