FHWA > Engineering > Pavements > Research > LTPP > FHWA-HRT-07-052 > Protocol P07 (Continuation) |
Long Term Pavement Performance Project Laboratory Materials Testing And Handling GuideProtocol P07 (Continuation)
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Extensometer reading at time j | Data Point |
---|---|
{H,V}i,1,k | 20th point in data file |
{H,V}i,2,k | 30th point in data file |
{H,V}i,5,k | 60th point in data file |
{H,V}i,10,k | 110th point in data file |
{H,V}i,20,k | 210th point in data file |
{H,V}i,50,k | Average 505th point through 515th point (11 points total) |
{H,V}i,100,k | 1010th point in data file |
For a 100-second creep test, the deformations at 50 seconds are used to calculate the Poisson's ratio for the experiment. To prevent a spike in the data from influencing the Poisson ratio value, the average of the 505th point through the 515th point (11 points total) is taken as the deformation at 50 seconds.
B3.2.4 Calculate deformations for each creep time j, face k, and orientation {H,V} of each specimen i.
Eq. B20
Where: D{H,V}i,j,k = the deformation for creep time j of face k of each specimen i, in.
{H,V}i,j,k = the extensometer reading for creep time i of face k of each specimen i, in.
{H,V}mini,k = the extensometer reading at the start of the creep test for each face k of each specimen i, in.
B3.2.5 Determine the axial load (Pi,j) for each creep time j of each specimen i.
Axial load at time j | Data Point |
---|---|
Pi,1 | 20th point in data file |
Pi,2 | 30th point in data file |
Pi,5 | 60th point in data file |
Pi,10 | 110th point in data file |
Pi,20 | 210th point in data file |
Pi,50 | 510th point in data file |
Pi,100 | 1010th point in data file |
B3.2.6 Determine the average axial load (Pi) on specimen i
Eq. B21
where: Pi = the average axial load for specimen i, lbs.
Pi,t = the axial load for specimen i at time = t, lbs.
B3.2.7 Calculate the average specimen thickness (tavg), the average specimen diameter (davg), and the average axial load (Pavg).
Eq. B22
Where: tavg = the average specimen thickness, in.
davg = the average specimen diameter, in.
Pavg = the average axial load, lbs.
ti = the thickness of specimen i, in.
di = the diameter of specimen i, in.
Pi = the axial load for specimen i, lbs.
B3.2.8 Calculate the deformation normalization factor (Cnormi) for each specimen i.
Eq. B23
Where: Cnormi = the deformation normalization factor for specimen i.
tavg = the average specimen thickness, inches.
davg = the average specimen diameter, inches.
Pavg = the average axial load, lbs.
ti = the thickness of specimen i, inches.
di = the diameter of specimen i, inches.
Pi = the axial load for specimen i, lbs.
B3.2.9 Calculate the normalized deformations (D{H,V}normi,j,k) for time j and face k of each specimen i.
Eq. B24
Where: D{H,V}normi,j,k = the normalized deformations for time j and face k of specimen i, inches.
D{H,V}i,j,k = the deformation for creep time j of face k of each specimen i, inches.
Cnormi = the deformation normalization factor for specimen i.
B3.2.10 Average deformation data sets
There are 14 "trim" data sets. A deformation data set consists of all the recoverable deformations calculated for a given orientation {H,V}, and time j. Average the deformation data sets by one of the following methods:
B3.2.10.1 Method 1: Normal Analysis
For each trim data set, remove the highest and lowest deformation and average the remaining four. This average shall be referred to as D{H,V}trimavgj for time j.
B3.2.10.2 Method 2: Variation of Normal Analysis
For each trim data set, remove the two highest and the two lowest deformations and average the remaining two. This average shall be referred to as D{H,V}trimavgj for time j.
B3.2.10.3 Method 3: Individual Analysis
For each trim data set, remove any deformations and average the remaining deformations. This average shall be referred to as D{H,V}trimavgj for time j.
B3.2.11 Calculate the Poisson's Ratio at time = 50.
Eq. B25
Where: ν = the Poisson's Ratio
DHtrimavg50 = the average horizontal trimmed deformation at time = 50, in.
DVtrimavg50 = the average vertical trimmed deformation at time = 50, in.
tavg = the average specimen thickness, in.
davg = the average specimen diameter, in.
B3.2.12 Calculate the creep compliance correction factor (Ccmply) for each time j.
Eq. B26
Where: Ccmplj = the creep compliance correction factor at time j.
DHtrimavgj = the average horizontal trimmed deformation at time j, in.
DVtrimavgj = the average vertical trimmed deformation at time j, in.
B3.2.13 Calculate the creep compliance for each time j.
Eq. B27
Where: Dj = the creep compliance at time j, 1/psi
DHtrimavgj = the average horizontal trimmed deformation at time j, in.
davg = the average specimen diameter, in.
tavg = the average specimen thickness, in.
Ccmplj = the creep compliance correction factor at time j.
Pavg = the average axial load, lbs.
GL = the extensometer gauge length (1 inch [25 mm] for a nominal 4-inch [102-mm] specimen diameter, 1.5 inches [38 mm] for a nominal 6-inch [152-mm] specimen diameter).
B3.3 Creep Compliance Data Analysis Flow Charts
B3.3.1 Main Procedure
B3.3.2 Subroutine 1
B3.3.3 Subroutine 2
An outline of the indirect tensile strength algorithm that is used in the "ITLTFHWA" software, and described in the report by Roque et al. is presented in section B4.2. The algorithm is described graphically in section B4.3.
B4.1 Subscript Convention
For the purpose of clarity, a subscript convention has been developed. The subscript 'i' represents the specimen number (i = 1, 2 or 3), the subscript 'j' represents the specimen face (j =1 or 2) and the subscript 't' represents the time at which a value was measured. Thus a variable may have up to three subscripts of the following form: Xi,j,t.
B4.2 Analysis
B.4.2.1 Invert Load Values
For each of the three specimens, multiply all load values by -1, so that compression values are positive.
B.4.2.2 Determine Cycle Start Time (tsi):
For specimen i, determine the time at which the load cycle starts. The load cycle start time is defined as the first time t that satisfies the following two requirements:
1) The load must continuously increase over the three data points subsequent to tsi, as shown below:
Eq. B28
2) The load must increase by at least 40 lbs (18 kg) over the three data points subsequent to tsi, as shown below:
Eq. B29
B4.2.3 Zero the Time Values
For each specimen i, subtract tsi from each time value, so that the load cycle starts at t = 0.
B4.2.4 Zero the Load Values
For each specimen i, subtract the initial load value, Pi,0 from each load value, so that the load at the time the cycle starts is 0.
B4.2.5 Calculate the Deformation Zero Value ({H,V}si,j)
For each specimen i, face j, and orientation {H,V}, the deformation zero value is equal to the average of the 10 deformation values prior to the load cycle start, as shown below:
Eq. B30
B4.2.6 Zero the Deformation Values
For each specimen i, face j, and orientation {H,V}, subtract {H,V}si,j from the respective deformation value.
B4.2.7 Determine the Failure Load (Pi,tfi)
B4.2.7.1 Determine tfi,j
For each specimen i, and face j, determine the time where Vi,j,t - Hi,j,t is at a maximum (tfi,j).
B4.2.7.2 Determine Time of Specimen Failure (tfi)
For each specimen i, the time of specimen failure (tfi) is the minimum of tfi,1 and tfi,2.
B4.2.7.3 Determine the Failure Load (Pi,tfi)
For each specimen i, the failure load is the load P corresponding to time tfi.
B4.2.9 Determine the Deformations at Half the Failure Load (Δ{H,V}i,j)
B4.2.9.1 Determine the Time of Half Failure Load (thi)
For each specimen i, thi is the time that satisfies the following equation:
Eq. B31
B4.2.9.2 Determine Deformations at Time thi
For each specimen i, face j and orientation {H,V}, select the deformations at time thi. This value shall be referred to as Δ{H,V}i,j.
B4.2.10 Calculate the Average Specimen Thickness and Diameter
Calculate the average specimen thickness (Tavg) and diameter (Davg) as shown below:
Eq. B32
Eq. B33
B4.2.11 Calculate the Deformation Normalization Factors (Cnormi)
For each specimen i, calculate the deformation normalization factors as shown below:
Eq. B34
B4.2.12 Calculate the Normalized Deformations (Δ{H,V}normi,j)
Eq. B35
B4.2.13 Average deformation data sets
There are 2 "trim" data sets. A deformation data set consists of all the normalized deformations calculated for a given orientation {H,V}. Average the deformation data sets by one of the following methods:
B4.2.13.1 Method 1: Normal Analysis
For each trim data set, remove the highest and lowest deformation and average the remaining four. This average shall be referred to as D{H,V}trimavg.
B4.2.13.2 Method 2: Variation of Normal Analysis
For each trim data set, remove the two highest and the two lowest deformations and average the remaining two. This average shall be referred to as D{H,V}trimavg.
B4.2.13.3 Method 3: Individual Analysis
For each trim data set, remove any deformations and average the remaining deformations. This average shall be referred to as D{H,V}trimavg.
B4.2.14 Calculate Poisson's Ratio (ν)
Eq. B36
B4.2.15 Calculate "Used" Poisson's Ratio (νused)
B4.2.15.1 Case 1: ν > 0.5
If the ν calculated in step B4.2.14 is greater than 0.5, then ν used = 0.5.
B4.2.15.2 Case 2: ν < 0.05
If the ν calculated in step B4.2.14 is less than 0.05, then ν used = 0.05.
B4.2.15.3 Case 3: 0.05 < ν < 0.5
If the ν calculated in step B4.2.14 is between 0.05 and 0.5, then ν used = ν.
B4.2.16 Calculate the Stress Correction Factors
For each specimen i, calculate the stress correction factors as follows:
Eq. B37
B4.2.17 Calculate the Indirect Tensile Strength
For each specimen i, calculate the indirect tensile strength as follows:
Eq. B38
B4.2.18 Calculate the Average Indirect Tensile Strength
Eq. B39
B4.3 Indirect Tensile Strength Analysis Flowcharts
B4.3.1 Main Procedure
B.4.3.2 Subroutine 1
LTPP LABORATORY MATERIAL HANDLING AND TESTING
LABORATORY MATERIAL TEST DATA
CREEP COMPLIANCE, RESILIENT MODULUS AND INDIRECT TENSILE STRENGTH
LAB DATA SHEET T07 - SAMPLE SUMMARY INFORMATION
ASPHALT CONCRETE LAYER (ASPHALTIC CONCRETE PROPERTIES)
LTPP TEST DESIGNATION AC07/LTPP PROTOCOL P07
LABORATORY PERFORMING TEST:___________________________________________________________
LABORATORY IDENTIFICATION CODE: ___ ___ ___ ___
1. STATE CODE: ___ ___ | 2. SHRP ID: ___ ___ ___ ___ |
3. LAYER NO: ___ | 4. FIELD SET: ___ |
DATA ITEM | SPECIMEN 1 | SPECIMEN 2 | SPECIMEN 3 |
5. TEST NO | ___ | ___ | ___ |
6. SAMPLE AREA (SA-) | ___ ___ | ___ ___ | ___ ___ |
7. LOCATION NO | __ __ __ __ __ __ | __ __ __ __ __ __ | __ __ __ __ __ __ |
8. LTPP SAMPLE NO | __ __ __ __ __ __ __ | __ __ __ __ __ __ __ | __ __ __ __ __ __ __ |
9. AVG. THICKNESS (mm) | ___ ___ . ___ | ___ ___ . ___ | ___ ___ . ___ |
10. AVG. DIAMETER (mm) | ___ ___ ___ . ___ | ___ ___ ___ . ___ | ___ ___ ___ . ___ |
11. BULK SPECIFIC GRAVITY | ___ . ___ ___ ___ | ___ . ___ ___ ___ | ___ . ___ ___ ___ |
12. COMMENT 1 | ___ ___ | ___ ___ | ___ ___ |
13. COMMENT 2 | ___ ___ | ___ ___ | ___ ___ |
14. COMMENT 3 | ___ ___ | ___ ___ | ___ ___ |
15. Other Comments |
1. STATE CODE: ___ ___ | 2. SHRP ID: ___ ___ ___ ___ |
3. LAYER NO: ___ | 4. FIELD SET: ___ |
DATA ITEM | SPECIMEN 1 | SPECIMEN 2 | SPECIMEN 3 |
RESILIENT MODULUS TEST | |||
16. DATA FILENAME, TEST 1 | _ _ _ _ _ _ _ _ . DAT | _ _ _ _ _ _ _ _ . DAT | _ _ _ _ _ _ _ _ . DAT |
17. TEST 1 TEMP. (°C) | ___ ___ . ___ | ___ ___ . ___ | ___ ___ . ___ |
18. DATA FILENAME, TEST 2 | _ _ _ _ _ _ _ _ . DAT | _ _ _ _ _ _ _ _ . DAT | _ _ _ _ _ _ _ _ . DAT |
19. TEST 2 TEMP. (°C) | ___ ___ . ___ | ___ ___ . ___ | ___ ___ . ___ |
20. DATA FILENAME, TEST 3 | _ _ _ _ _ _ _ _ . DAT | _ _ _ _ _ _ _ _ . DAT | _ _ _ _ _ _ _ _ . DAT |
21. TEST 3 TEMP. (°C) | ___ ___ . ___ | ___ ___ . ___ | ___ ___ . ___ |
22. ANALYSIS FILENAME | _ _ _ _ _ _ _ _ . MRO | ||
CREEP COMPLIANCE TEST | |||
23. DATA FILENAME, TEST 1 | _ _ _ _ _ _ _ _ . DAT | _ _ _ _ _ _ _ _ . DAT | _ _ _ _ _ _ _ _ . DAT |
24. TEST 1 TEMP. (°C) | ___ ___ . ___ | ___ ___ . ___ | ___ ___ . ___ |
25. DATA FILENAME, TEST 2 | _ _ _ _ _ _ _ _ . DAT | _ _ _ _ _ _ _ _ . DAT | _ _ _ _ _ _ _ _ . DAT |
26. TEST 2 TEMP. (°C) | ___ ___ . ___ | ___ ___ . ___ | ___ ___ . ___ |
27. DATA FILENAME, TEST 3 | _ _ _ _ _ _ _ _ . DAT | _ _ _ _ _ _ _ _ . DAT | _ _ _ _ _ _ _ _ . DAT |
28. TEST 3 TEMP. (°C) | ___ ___ . ___ | ___ ___ . ___ | ___ ___ . ___ |
29. ANALYSIS FILENAME | _ _ _ _ _ _ _ _ . OUT | ||
INDIRECT TENSILE STRENGTH TEST | |||
30. DATA FILENAME | _ _ _ _ _ _ _ _ . DAT | _ _ _ _ _ _ _ _ . DAT | _ _ _ _ _ _ _ _ . DAT |
31. TEST TEMP. (°C) | ___ ___ . ___ | ___ ___ . ___ | ___ ___ . ___ |
32. ".OUT" FILENAME | _ _ _ _ _ _ _ _ . OUT | ||
33. ".STR" FILENAME | _ _ _ _ _ _ _ _ . STR | ||
34. ".FAM" FILENAME | _ _ _ _ _ _ _ _ . FAM |
GENERAL REMARKS:___________________________________________________________________________ | |
SUBMITTED BY, DATE | CHECKED AND APPROVED, DATE |
______________________________ | ______________________________ |
LABORATORY CHIEF Affiliation______________________ | Affiliation______________________ |
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