TCVN 8867: 2011 is converted from 22 TCN 251 98 as regulated in Section 1, Article 69, Law on Technical Standards and Regulations and point a, clause 1, Article 7, Decree No. 1272007NĐCP dated 182008 by the Government detailing implementation of some articles under Law on Technical Standards and Regulations. TCVN 8867: 2011 is composed by Institute of Transport Science and Technology, proposed by Ministry of Transport, verified by Directorate for Standards, Metrology and Quality, and announced by Ministry of Science and Technology.
VIETNAM STANDARDS TCVN 8867 : 2011 First Edition FLEXIBLE PAVEMENT – STANDARD TEST METHOD FOR DETERMINATION OF ELASTIC MODULUS OF PAVEMENT STRUCTURE USING BENKELMAN BEAM HANOI - 2011 Table of Contents Scope of application References .4 Terminology and Definition 4 Equipment and Tools .4 Conduction .5 Processing deflection measurement results Appendix A .9 Appendix B .11 Appendix C .13 Appendix D .14 Appendix E .18 Appendix F .22 Foreword TCVN 8867: 2011 is converted from 22 TCN 251 - 98 as regulated in Section 1, Article 69, Law on Technical Standards and Regulations and point a, clause 1, Article 7, Decree No 127/2007/NĐ-CP dated 1/8/2008 by the Government detailing implementation of some articles under Law on Technical Standards and Regulations TCVN 8867: 2011 is composed by Institute of Transport Science and Technology, proposed by Ministry of Transport, verified by Directorate for Standards, Metrology and Quality, and announced by Ministry of Science and Technology FLEXIBLE PAVEMENT - STANDARD TEST METHOD FOR DETERMINATION OF ELASTIC MODULUS OF PAVEMENT STRUCTURE USING BENKELMAN BEAM Scope of application This standard provides regulations on test method for determining elastic modulus of flexible pavement structure for highway, using Benkelman beam, for the purpose of evaluating load bearing capacity of the new pavement or quality of the pavement in service References The following references are necessary for applying these standards For those with year of issuance, apply the versions stated expressly For references without year of issuance, apply the latest version including amendment thereof (if any) TCVN 4054:2005, Highway – Design Requirements; TCVN 5729:1997, Expressway – Design Requirements; TCXDVN 104:2007*), Urban Road - Design Requirements; 22 TCN 211-06*), Flexible Pavement – Design Requirements and Guidelines Terminology and Definition For the purpose of this standard, the following terms are used: 3.1 Elastic modulus of pavement structure Elastic modulus of pavement structure refers to a property of resistance to deformation of the embankment - pavement structure including the pavement and the working area of the embankment under the effect of standard wheel load 3.2 Rebound deflection Rebound deflection pertains to recoverable deflection after the load is removed (when the standard wheel displaces from the measurement location) Equipment and Tools 4.1 Benkelman beam must have length from the front support beam to the beam tip of at least 2.0m and ratio of the beam lever shall not be less than 2:1 (Refer to Appendix B) 4.2 Prior to each working shift, it is necessary to verify the beam accuracy by comparing results of vertical displacement measurement at the beam tip with the counterpart at the end of the end of the lever, at the rear of the beam, taking into account the ratio of levers of the beam If deviation is over 5%, check linking at joints, hinges, pivots and the smoothness and sensitivity of the beam (Refer to Appendix B) 4.3 A test truck/trailer is a vehicle of which the rear axle is single one, dual (tyred) wheels and the gap between two dual wheels is at least 5cm, the test tyre of the rear axle must be new Parameters of the truck’s rear axle are only in tolerances of 5% as compared to Table Table – Parameters of the standard truck’s rear axle Name of parameters Required Rear axle load, Q, kN 100 Wheel pressure on the pavement, p, MPa 0,6 Equivalent diameter of the dual wheel track, D, cm 33 *) Standards TCN and TCXDVN will be converted into TCVN 4.4 The load on vehicles must be symmetric, balanced, with no change of position and rear axle load shall not alter during the pavement deflection measurement In the course of measurement, the truck must be shielded to prevent rain penetration and material drops 4.5 To determine the axle load, we must conduct weighing the rear axle with vehicle weighing system or using hydraulic jack with pressure gauge which is calibrated and the pressure scale not more than 0.02MPa 4.6 To measure for examining pneumatic pressure inside the wheels to keep it unchanged during pavement deflection measurement (See Appendix B) Conduction 5.1 Preparation 5.1.1 Prior to measurement, check the dual wheels track area S b by jacking the rear axle up, cleaning and applying grease on the tyres, turning the greased tyres downward, then lowering the jack to trace the wheels track on the cross-section papers The dual wheels track area S b is defined as the area of grease trace on the cross-section papers Equivalent diameter of the truck’s dual wheels track is D b and the wheels pressure on the pavement, pb are calculated with the following formula: Of which: Db refers to equivalent diameter of the truck’s dual wheels track, in cm; Sb is the dual wheels track area of the test truck, in cm2; pb means the wheels pressure on the pavement of the truck, in MPa; Qb is the load of truck’s rear axle, in kN 5.1.2 Based on preliminary survey, management documents of the road and field visit, we may divide the road into homogeneous sections and choose representative sub-sections from each homogeneous section following such principles as: 5.1.2.1 Sections are deemed as being homogeneous when holding identical factors like: Type of embankment and pavement on moisturizing conditions, state of drainage, status of pavement surface, structure of pavement, type of the top soil, traffic volume and so on These figures will be obtained in reference to the road documents at road management agencies and data collected by site investigation carried out by experienced expert teams (refer to Appendix A); 5.1.2.2 To choose representative sub-sections on each homogeneous section: The representative sub-section shall range from 500m to 1000m length On each representative sub-section, select 20 test spots/lane For homogeneous sections which are particularly short but quite different from the surrounding sections (those with complicated geological and hydrological conditions or soft ground), even less than 100m, still we have to measure for at least 20 test spots/lane 5.1.3 If the road to be evaluated fail to have basic data to apply the division of road into homogeneous sections as described in section 5.1.2, we measure as below: 5.1.3.1 For the stage of Detailed Design or Shop Drawings, conduct measurement on the whole alignment with density at least 20 test spots/1 lane/1km; 5.1.3.2 For the stage of investment project preparation, management of highway operation or other works comply with the Client’s requirements, conduct measurement with intensity of at least to 10 points/lane/1km 5.1.4 Choosing location of test spots (measurement points/test location) 5.1.4.1 Test spots of deflection measurement are preferably arranged in the outer wheel track (to be 0.6m ÷ 1.2m from the road edges), which commonly has higher deflection than the inner one In case it is visually observed pavement status in the inner wheel track and the outer one are damaged uniformly, it is advisable to utilize two beams at the same time on both wheel tracks to take the larger value as typical deflection value for the cross section of the measured lane 5.1.4.2 For multi-lane driveway, checking visually shows that pavement status varies for lanes, measure the deflection for the weakest lane Measurement value at each position of lane will be typical for deflection at the road cross section (Refer to Appendix C) 5.1.4.3 To mark paint on test spots The first test spot and the 20 th test spot should be coincide with the cross section at station of Kilometer posts or piles with one hundred meters unit (H pile) 5.2 Deflection measurement along the pavement 5.2.1 Procedure of pavement (surface) deflection measurement 5.2.1.1 To get the truck advanced to the deflection measurement location, then to place the measurement probe of Benkelman beam resting on the pavement in the middle of the gap of dual wheels couple after the truck To have the beam plunger vibrated slightly, then monitoring the pointer of a dial indicator until the deflection is found stable (in 10s, pointer does not shift over 0.01mm), record the starting reading on the dial indicator (as I 0) 5.2.1.2 The truck shall be moved forward with creep speed of about 5km/h until the rear axle of the wheels to be at least 5m far from the test spot, then knocking gently on the plunger to check the sensitivity of dial indicator To oversee the dial indicator until deflection becomes stable, then recording the final reading (referred to as I 5) The difference of two readings on the dial indicator multiplied by the beam’s lever ratio is the value of the pavement rebound deflection on the test spot (symbolized as Ii) 5.2.1.3 In the course of pavement deflection measurement, clarify station of the test spot, weather and moisturizing conditions and comments on the pavement status at the test spot on the test form (refer to Appendix C) NOTE 1: When measuring the pavement deflection, not measure at positions where the pavement are considerably damaged such as: elasticity phenomena, crack, etc These are not typical for the area of deflection measurement It is however necessary to record, describe such positions to apply treatment solutions afterwards 5.2.2 Measurement of pavement temperature: So as to adjust results of deflection measurement for calculated temperatures later, it is a must to measure the ambient air temperature and pavement temperature for once in hour during deflection measurement along the pavement Measurement of the pavement temperature is only required for pavement structure with the asphalt top layer thickness is 5cm or more This is how to measure the pavement temperature: –A hole should be made with hammer and mandrel to a depth of 45mm on the pavement near the deflection test point; –Then the hole should be filled with water or glycerol to the half depth thereof, waiting for a few minutes; –Then insert a thermometer to measure temperature of the fluid in the hole until the temperature is unchanged, record measured temperature values (T 0C) NOTE 2: - To prevent against solar radiation to Benkelman beam and the measurement probe and the plunger from settling down to the asphalt pavement in high temperature, with prejudice to the accuracy of the measurement results, not measure defection when the pavement temperature is over 40 oC - To prevent the measurement results being affected by the truck shadow or any object 5.2.3 To organize traffic safety during measurement process All members working for measurements including drivers must be trained in measurement profession NOTE 3: Traffic safety organization may be arranged by using barrier, traffic signs in combination with person holding traffic control flag Processing deflection measurement results 6.1 Processing deflection measurement results 6.1.1 Rebound deflection calculated at the test spot (i) representing the pavement cross section (L itt) is determined by formulae: Including: Li refers to the pavement deflection measured at the (i) test spot regardless of other effects by the truck loading, unfavorable season and the pavement temperature, unit in mm; Kq means the coefficient of measurement results adjustment by parameters of the rear axle of the test truck to the results of standard truck rear axle Kq is calculated by formulae: Of which: pb, Db , p and D are determined as in section 5.1.1 and 4.3 Km is the deflection adjustment factor to the most unfavorable season in a year; Kt is the deflection adjustment factor at the measured temperature to that of the calculated temperature (TttoC) 6.1.2 When it becomes impracticable to monitor rules of deflection changes by season and by temperature, it is allowed to use K m and Kt from observation performed in the locality for routes with similar conditions (See Appendix D) 6.1.3 After having determined calculated deflection of measurement location (L itt), it is necessary to eliminate crude errors from the set of collected values on each section by standards for elimination of extreme observations in the theory of statistics and probability (Refer to Appendix E) 6.2 To determine typical deflection and typical modulus of elasticity for each test section 6.2.1 Value of typical rebound deflection on homogeneous section is calculated as average deflection of the representative sub-section on such homogenous section 6.2.2 Depending on requirement and scope of the project, typical rebound deflection for each test section is calculated for both directions for each direction or each lane of the test road section 6.2.3 Unless basic data is available for dividing the road into homogeneous sections as stated in section 5.1.2, value of typical rebound deflection for each test section is calculated by the following formulae: In which: Ldt is typical rebound deflection for each test section; Ltb pertains to average deflection of the test section, in mm Value Ltb is calculated by below formulae: n is number of measurement; δ is the mean square deviation of the test section, in mm Value δ is calculated by below formulae: K is the probability factor taken upon grade and class of road, to be determined as below: – Expressway and road grade l (classified by TCVN 5729:2007 TCVN 4054:2005), urban expressway (classified by TCXDVN 104:2007), K = 2.0; – Road grade ll (classified by TCVN 4054:2005), urban major roads (classified by TCXDVN 104:2007), K = 1.64; – Road grade lll (classified by TCVN 4054:2005), K = 1.3; – Road grade lV to VI (classified by TCVN 4054:2005), frontage roads, inner city roads (classified by TCVN 4054:2005), K = 1.04 6.2.4 Value of typical modulus of elasticity for each test section (E dh) is determined with formulae: Including: 0.71 is a constant of deflection measurement; p indicates standard wheel pressure on the pavement, p = 0.6 MPa; D refers to equivalent diameter of the standard wheel tracks area, D = 33 cm; µ is Poisson’s ratio, µ= 0,3; Ldt is typical rebound deflection determined in section 6.2.1 Appendix A (For reference) NAME OF LAB - SOCIALIST REPUBLIC OF VIETNAM Independence - Freedom - Happiness ………, day … month … year …… SECTION DIVISION FOR EVALUATION OF FLEXIBLE PAVEMENT STRUCTURE STRENGTH Project: Section: From: Km To: Km Testing date: Name and address of the Laboratory: Kilometer 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 Cross section - Left side 1.5 m 1.5 m 0.5 m - Surface 10.5 m 7.0 m 7.0 m - Right side 1.5 m 1.5 m 0.7 m Drainage - Left ditch - Right ditch Good drainage Poor drainage Poor drainage Mortared riprap - - - Pond - - - Type of embankment – pavement by moisturizing condition I II III III Pavement status - Good - Crack - Rutting - - _ - Local settlement - Spalling - Horizontal sliding - Broken, pot hole (repaired/unrepai red) ++ ++ ++ New Pavement structure Top soil layer Reinforced Old cm fine AC year1997 cm medium AC year 1990 cm fine AC year 1979 cm medium AC cm P.Macad’ year 1985 cm P.Macad’ ,, 15 cm Macadam cm P.Macad’ year 1976 22 cm riprap 22 cm rubble stone 22 cm riprap ,, ,, Heavy sandy clay Clayed sand Sandy clay 1000 500 200 Calculated traffic volume (PMU/day night) Test spot at observation station Final sub-section Tested by Chief of Lab LAS-XD (VILAS) Lab Line Agency (Signed and sealed) (Signed and sealed) The Engineer Appendix C (For reference) NAME OF LAB - SOCIALIST REPUBLIC OF VIETNAM Independence - Freedom - Happiness ………, day … month … year …… DATA SHEET OF REBOUND DEFLECTION MEASUREMENT USING BENKELMAN Project: .Sheet No : Number of sheets : Region (Province): Implementing agency: Measured by: .Time of measurement : Measure with station direction increasing/decreasing: Load conversion factor of truck axle Kq = Ratio of beam lever 1, left wheel K1C = Ratio of beam lever 2, right wheel K2C = Km + Distance from truck center to Measurement pavement center: hour : Pavement temperature: Weather : State of pavement: Km Km Water level of both sides high/low/average: + + Conclude: Type of embankment – pavement by moisturizing condition l / ll / lll Chainage Factor Km: Factor Kt : Left wheel io i5 Right wheel littt i0 i5 Lmax littp NOTE C.1: io, i5 are readings on the dial indicator when the truck displaces from the test spot of 0m and more than 5m; Km is the deflection adjustment factor to the most unfavorable season; Kt is the deflection adjustment factor at the measured temperature to that of the calculated temperature; littt or littp refers to the rebound deflection at the left wheel or right wheel calculated by formulae: littt or littp = KC x Kq x Km x Kt x (io- i5 ) lmax is the maximum value of littt and littp Tested by Chief of Lab LAS-XD (VILAS) Lab Line Agency (Signed and sealed) (Signed and sealed) The Engineer Appendix D (Regulations) Determination of the most unfavorable season, conversion factor of season and pavement temperature D.1 When it is possible to set up fixed observation positions in the locality – Selecting measurement location: To perform deflection measurement in sections representing type of pavement structure and kind of dryness/moisture of the embankment It is advisable to choose representing sections very near to fixed reference objects for eye-catching, such as Kilometer posts or guide signs Then choose about 20 measurements points (or the so-called test point/spots) Then mark these measurement points in circle of 10cm diameter with anti-abrasion, waterproof and light colored paint; coordinates of the measurement point (in relation to reference object) must be clarified in the summarized statistical sheet, under the form of fraction, of which the numerator is the station of the measurement point and the denominator is the distance from the measurement point to the road edge to the right (R) or to the left (F) of the road – – Time of measurement: This work is implemented in several years Every one, to measure in the same day, in the morning and when the pavement have highest temperature (about 1-2pm) – How to measure: Measurement of deflection in fixed observatory points is similar to that for test spots along the pavement including measuring pavement temperature in testing During test in measurement points, special attention should be paid to placement of test vehicle wheels within the circle marked on the pavement surface – Processing of results after measurement: Using statistical analysis method of deflection measurement data to determine the most unfavorable season in a year, deflection adjustment factor to the most unfavorable season in year (Km) and deflection adjustment factor at measured temperature to calculated temperature (Kt) D.2 When it is impossible to set up fixed observatory positions in the locality: D.2.1 Choosing the most unfavorable season: We may take the most unfavorable season in year of the road passing by localities as in Table D.1 The most unfavorable month is taken from middle of the most unfavorable time Table D.1 – The most unfavorable time of localities nationwide No Name of locality Most unfavorable time No in year (month) Name of locality Cao Bằng June to September Lạng Sơn June to September 10 Phú Thọ June to September Hà Giang June to September 11 Bắc Giang June to September Lào Cai May to October 12 Hà Nội June to September Lai Châu June to September 13 Quảng Ninh June to September Điện Biên June to September 14 Thanh Hóa June to October Sơn La June to September 15 Nghệ An Thái Nguyên June to September 16 Quảng Bình 17 Hoàng Sa July to November Vĩnh Phúc Most unfavorable time in year (month) 27 Sóc Trăng May to October June to November September to December June to October 18 Thừa Thiên Huế September to January 28 Cần Thơ June to November 19 Đà Nẵng October to December 29 Phú Quốc June to November 20 Quảng Ngãi 21 Quy Nhơn October to January 30 Cà Mau October to December 31 Kiên Giang June to November June to November 22 Phú Yên October to December 32 Bình Dương 23 Khánh Hòa October to December 33 Lâm Đồng June to November June to October 24 Bình Thuận June to October 34 Đắc Lắk June to October 25 Bà Rịa Vũng Tàu June to October 35 Gia Lai June to October 26 TP Hồ Chí Minh June to October D.2.2 Deflection adjustment factor to the most unfavorable season in year (Km): To determine (Km) as below: + With type of embankment-pavement structure limiting effect of moisturizing sources – Type I (constant dryness, refer to Appendix B of 22TCN 211-06): Embankment is not frequently submerged, underground water level is 1.5m lower than pavement bottom when the embankment is of clay and sandy clay or 0.8m when the embankment is filled by clayed sand with good drainage of surface water In case of submerge in no longer than months, the shoulder must be filled with sandy clay or clay soil with density K ≥ 0.95 and the shoulder is 1.5 to 2.0m wider Pavement structure should have the surface layer of waterproofing and base courses of tightness material, the embankment is soil compacted to density K ≥ 0.95 or consolidated soil, sand with binder materials Furthermore, type I may be the embankment-pavement under effect of moisturizing sources but of no change seasonally, deflection of the pavement structure is independent on the moisture (Km=1.0) while depending on the temperatures + With embankment-pavement structure type with effect of seasonally interchangeable moisturizing sources – type of embankment – pavement structure by moisturizing condition II (moderate moisture, refer to Appendix B of 22TCN 211-06) or III (over-moisture, refer to Appendix B of 22TCN 211-06): Low embankment, narrow shoulder filled with clayed sand soil to be poorly compacted, with regular underground water, poor surface water drainage and under effect of underground water Pavement structure has water-permeable surface layer, base is non-watertight Seasonal conversion factor K m may be taken from Table D.2 herein under: Table D.2 – Deflection adjustment factor to the most unfavorable season in year to the K m) State of road surface Season Month Factor Km Spring 2-4 1.06 Summer - Fall 5-9 1.00 Winter 10 - 1.14 Spring 2-4 1.18 Summer - Fall 5-9 1.00 Winter 10 - 1.47 Spring 2-4 1.07 Summer - Fall 5-9 1.14 Winter 10 - 1.00 Spring 2-4 1.24 Summer - Fall 5-9 1.47 Winter 10 - 1.00 Spring 2-4 1.14 Northern provinces Water tightness and no crack Surface with crack and water penetration Central Region provinces Water tightness and no crack Surface with crack and water penetration Southern and the Central Highlands provinces Water tightness and no crack Surface with crack and water penetration Summer - Fall 5-9 1.00 Winter 10 - 1.07 Spring 2-4 1.47 Summer - Fall 5-9 1.00 Winter 10 - 1.24 NOTE D.1: - Northern provinces includes all northern mountainous provinces, the Northern Delta, and Thanh Hóa, Nghệ An, Hà Tĩnh, Quảng Bình Province - Central Region provinces are those from Quảng Trị to Ninh Thuận; - Southern and the Central Highlands provinces including the Southeastern provinces, Southwestern provinces and Lâm Đồng Đắc Lắk, Đắc Nông, Gia Lai, Kon Tum D.2.3 Deflection adjustment factor at measured temperature to calculated temperature (K t): + Pavement structure has the top layer coated with asphalt of 5cm to 10cm thickness: Deflection adjustment factor at measured temperature (ToC ) to calculated temperature at 300C by this formulae: of which: A is a constant depending on heat stability of the asphalt coating course thickness With dense-graded asphalt concrete with stone powder, we assume A = 0.35, for asphalt concrete without stone powder or penetration macadam, take A = 0.30 + Pavement structure with top layer material using asphalt of over 10cm thickness: Determine deflection adjustment factor at measured temperature (T oC) by the following formulae: Of which: Kt(10) is deflection adjustment factor at measured temperature ToC to 10oC ; K30(10) refers to deflection adjustment factor at 30oC to 10oC Kt(10) and K30(10) is determined by monograph in Figure D.1 NOTE D.1: 1) Digits on broken line curves indicate the gross thickness of the asphaltic top layer when being tested with Benkelman beam; 2) Digits on solid line curvatures purports gross thickness of the asphaltic top layer of when testing with jacking of pressure board Figure D.1 – Monograph for determination of deflection conversion factor of the asphaltic at temperature top layer T0C and 30 0C to 100C Appendix E Standards for elimination of extreme observations (Regulations) Giving a sequence of n observations to be hypothesized to distribute following standard rules: x 1, x2, x3, xn Considering elimination of k extreme observation from the statistical sequence, we conduct with rule as below: – Step 1: + Re-arrange the observations sequence of xi into sequence x1 ≤ x2 ≤ xn + Calculate average value of the sequence by formulae: – Step 2: Calculate comparative value by this manner: + When it is skeptical of k1 maximum observation value, calculate this value by the following formulae: of which: Is arithmetic mean of (n-k1) remaining observations, after isolating k maximum observations from the sequence + When it is skeptical of k2 minimum observation value, calculate this value by the following formulae: of which: Is arithmetic mean of (n-k2) remaining observations, after isolating k2 minimum observations + When it is skeptical of k1 maximum value and k2 minimum value, calculate the value: of which: Is arithmetic mean of [n-(k1+k2)] remaining observations, after separating (k 1+k2) extreme observations from the sequence – Step 3: Compare calculated values L kmax, Lkmin or Lk with standard value Cα which are set in available calculations and compare as below: + If less than Cα then such extreme observations may be eliminated from the set of statistics + If more than sequence Cα then there is no basis to eliminate such extreme observations from the statistical EXAMPLE : Results of deflection measurement for one section obtain the sequence of data (1/100 mm): 0.79, 0.73 , 0.65 , 0.28 , 0.80 , 0.38 , 0.58 , 0.94 , 1.05 , 0.95 , 1.15 , 1.29 , 1.28 , 1.23 , 1.52 , 1.57 , 2.31 , 1.59 , 1.63 Eliminate crude errors if any Solution: – Re-arrange the sequence of numbers: 0.28, 0.38, 0.58, 0.65, 0.73, 0.79, 0.80, 0.94, 0.95, 1.05, 1.15, 1.23, 1.28, 1.29, 1.52, 1.57, 1.59, 1.63, 2.31, 2.63 – Calculate: x = 1.17 + We have doubts of maximum results 2.31 and 2.63 Consider whether it is possible to eliminate these two results or not? Perform as below: Apply standards for elimination of extreme observations for the case k = (for two numbers 2.31 and 2.63 ) Consulting the table: C0.05 = 0.484; C0.10 = 0.530 Compare Lk max < C0.05 < C0.10, we have basis to eliminate both extreme observations 2.31 and 2.63 from above sequence of deflection measurement data + If we suspect all maximum values 2.31, 2.63 and minimum values 0.28, 0.38 of above sequence, whether we have basis to eliminate them? Carry as below: Apply standard for elimination of extreme observations for the case k = (for two numbers 2.31, 2.63); k2 = (for two numbers 0.28, 0.38) Referring to the table n = 20, k = we have C0.05 = 0.299 C0.10 = 0.339 As such Lk < C0.05 < C0.10 Conclusion: We may eliminate all of observations 0.28, 0.38, 2.31 and 2.63 from above sequence of deflection measurement data Table E.1 – Standard value Standard value k Cα Cα with value α = 0,10 10 n 0.011 0.098 0.003 0.200 0.038 0.280 0.091 0.020 0.348 0.148 0.056 0.404 0.200 0.095 0.038 0.448 0.248 0.134 0.068 10 0.490 0.287 0.170 0.098 0.051 11 0.526 0.326 0.208 0.128 0.074 12 0.555 0.361 0.240 0.159 0.103 0.062 13 0.578 0.388 0.270 0.186 0.126 0.082 14 0.600 0.416 0.298 0.212 0.150 0.104 0.068 15 0.611 0.436 0.322 0.236 0.172 0.124 0.086 16 0.631 0.458 0.342 0.260 0.194 0.144 0.104 0.073 17 0.648 0.478 0.364 0.282 0.216 0.165 0.125 0.092 18 0.661 0.496 0.384 0.302 0.236 0.184 0.142 0.108 0.080 19 0.676 0.510 0.398 0.316 0.251 0.199 0.158 0.124 0.094 20 0.688 0.530 0.420 0.339 0.273 0.220 0.176 0.140 0.110 0.085 25 0.732 0.588 0.489 0.412 0.350 0.296 0.251 0.213 0.180 0.152 30 0.766 0.637 0.523 0.472 0.411 0.359 0.316 0.276 0.240 0.210 35 0.792 0.673 0.586 0.516 0.458 0.410 0.365 0.328 0.294 0.262 40 0.812 0.702 0.622 0.554 0.499 0.451 0.408 0.372 0.338 0.307 45 0.826 0.724 0.648 0.586 0.533 0.488 0.447 0.410 0.378 0.384 50 0.840 0.744 0.673 0.614 0.562 0.518 0.477 0.442 0.410 0.380 Standard value Cα with value α = 0,05 0.003 0.051 0.001 0.125 0.018 0.203 0.055 0.010 0.273 0.106 0.032 0.326 0.146 0.064 0.022 0.372 0.194 0.099 0.045 10 0.418 0.233 0.129 0.070 0.034 11 0.454 0.270 0.162 0.098 0.054 12 0.489 0.305 0.196 0.125 0.076 0.042 13 0.517 0.337 0.224 0.150 0.098 0.060 14 0.540 0.363 0.250 0.174 0.122 0.079 0.050 15 0.556 0.387 0.276 0.197 0.140 0.097 0.066 16 0.575 0.410 0.300 0.219 0.159 0.115 0.082 0.055 17 0.594 0.427 0.322 0.240 0.181 0.136 0.100 0.072 18 0.608 0.447 0.337 0.259 0.200 0.154 0.116 0.086 0.062 19 0.624 0.462 0.354 0.277 0.209 0.168 0.130 0.099 0.074 20 0.639 0.484 0.377 0.299 0.238 0.188 0.150 0.115 0.088 0.066 25 0.696 0.550 0.450 0.374 0.312 0.262 0.222 0.184 0.154 0.126 30 0.730 0.599 0.506 0.434 0.376 0.327 0.283 0.245 0.212 0.183 35 0.762 0.642 0.554 0.482 0.424 0.376 0.334 0.297 0.264 0.235 40 0.784 0.672 0.588 0.523 0.468 0.421 0.378 0.342 0.310 0.280 45 0.802 0.696 0.618 0.556 0.502 0.456 0.417 0.382 0.350 0.320 50 0.820 0.722 0.646 0.588 0.535 0.490 0.450 0.414 0.383 0.356 NOTE E.1: Meanings of standard value level α= 0.10 or α= 0.05 , etc that is probability of hypothesis elimination is 0.10 or 0.05 , etc if the hypothesis is correct Appendix F (Regulations) Accumulated deviation method for delimiting sections of deflection measurement results F.1 Foreword Rebound deflection of the pavement surface is a function of various dependent variables: type of pavement, pavement structure, type and status of the embankment ground, traffic volume, time of pavement use, temperature of the pavement and so forth Because there are too many dependent variables, as a matter of fact, there is always discrepancy between values of measured deflection no matter how we shorten distance of measurement points As a result, aiming at evaluating bearing capacity of the road, it is needful to delimit the road into typical sections, processing statistically deflection measurement results for evaluation The ground for sectionalizing is the difference along the pavement of aforesaid dependent variables obtained from existing documents from road managerial agencies and data collected by field investigation For particular reasons, if this is impossible, we have no way but basing on alignment chart of deflection measurement to fix sections by some approaches Most simply, we sectionalize subjectively by visual check at which location similar sub-sections are grouped Moreover, we may employ the analytical method of “accumulated difference” applied in discontinuous variables called “Accumulated Deviation” method for section division F.2 “Accumulated Deviation” Method A mathematical based method is that a variable Z x (which is determined as the difference between the area of curvature of alignment deflection measurement at any distance and total area calculated from the median of deflection for the whole route measured at the same distance) is charted following the function of alignment distances Margins of sections will occur in positions where the gradient of chart Zx – x alternates (See Figure F.1, F.2 and Table F.1) Of which: Si refers to actual area of the distance i Value Si = Ltb x Δxi; Δxi is the length of the distance i; Ltb pertains to average deflection of the distance i; Ln is the total length of the route to be measured for deflection From this preliminary sectionalizing results we determine typical rebound deflection (L dt) for each section, consider and decide whether two or more sections can be merged, for the purpose of actual construction and economic factors? With the high-ranking top layer (dense-grade asphalt concrete) on road grade I, II, expressway, arterial urban road, roads inside large factories, two adjacent sections may be merged into one if the difference of typical rebound deflection (L dt) is not more than 10% With the lower ranking top course of road grade III, IV with the surface layer coated with cold-mixed and moisture asphalt concrete, and pavements of: penetration macadam, water bound macadam, inorganic binder consolidated stone (the upper has bituminous layer), two adjacent sections can be merged if the typical rebound deflection (Ldt) discrepancy does not exceed 15% Sections less than 500m unless otherwise being two weak sections (elasticity, collapse, settlement) should be merged into sections next to them to lessen unnecessary complication (Refer to Figure F.4) Accumulated area Ai = ri dx Figure F.1 –Accumulated deviation method for delimiting sections of continuous variables Figure F.2 – Example of delimitation of section by accumulated deviation method Figure F.3 – Example of rebound deflection chart by order of measurement points on National Highway 1A, section Ho Chi Minh City – Can Tho Table F.1 – Accumulated Deviation Method of Section Delimitation for Deflection Measurement Results Order Station Length of Pavement Accumulated of distances Δxi deflection length of meas (100m) at the distances ΣΔxi urem measurem (100m) ent ent points location Li n (1/100 mm) Average deflection of distances Itbi (1/100mm) Actual area of distance Si Accumulate d area of distances ΣSi Accumulated deviation zx Statistical value of Designed divided distances deflection Itk Itbki , αk 0 Km +000 Δx1 l1 Δx1 l1 Δx1 l1 S1 S1 - Φ.Δx1 100 Δx2 I2 Δx1+Δx2 (l1+ l2)/2 Δx2 (l1+l2)/2 S1 +S2 S1+S2Φ(Δx1+Δx2) 400 Δx3 l3 Δx1+ Δx2+ Δx3 (l2+ l3)/2 Δx3 (l2+l3)/2 S1+ S2 +S3 S1+S2+S3 Φ(Δx1+Δx2+Δx3) ltbk=average(:) ………………… 700 Km +000 200 300 400 ………… n ………… Δxi ………… ………………… li Δx1+ + Δxi …………… …………………… ………… ………… (Ii-1+ li)/2 Δxi (li-1+li)/2 S1 + + Si ΣSi - Φ ΣΔxi Φ =ΣSi;/ΣΔxi ltbk+ Kδk δk= stdev(:) ………… Figure F.4 – Example of rebound deflection chart by stations of measurement points on National Highway 1A, section Ho Chi Minh City – Can Tho ... apply the versions stated expressly For references without year of issuance, apply the latest version including amendment thereof (if any) TCVN 4054:2005, Highway – Design Requirements; TCVN 5729:1997,... detailing implementation of some articles under Law on Technical Standards and Regulations TCVN 8867: 2011 is composed by Institute of Transport Science and Technology, proposed by Ministry of... D .14 Appendix E .18 Appendix F .22 Foreword TCVN 8867: 2011 is converted from 22 TCN 251 - 98 as regulated in Section 1, Article 69, Law on Technical