Structural Evaluation of Flexible Pavement

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Structural Evaluation of Flexible Pavement

Abhishek R, Asst. Professor,

Shivani Nagaraj*, Sushmitha S, Narendra Kumar, Chendan T.M., Students, Department of Civil Engineering, JSSATE Bangalore-560060, India.

Abstract:- Pavement maintenance is one of the most important aspect of highway engineering specially in a country like India because many of the pavements are reaching their end of service life. India witnesses mixed vehicular traffic thereby worsening the condition of the pavement. Rapid industrialization and urban growth in India has led to increased traffic and excessive usage of the roads which further adds as a catalyst to the same. Hence, pavement maintenance is a necessary measure for safety and cost efficiency as rehabilitation of pavement is very expensive. Pavement acts as a parameter for the progress of a nation, hence maintenance plays an important part for the growth of economy, commute and also increases the standard of living. The intention of this project is to study the structural stability of pavement using Benkelman Beam Deflection method and to decide the overlay to compensate for the structural instability if persists. Correction factors namely seasonal correction and temperature correction were also carried out. The results of these tests have been discussed in detail in this paper.

Key Words: Benkelman Beam Deflection Method, Pavement maintenance, Structural Evaluation, Overlay

  1. INTRODUCTION

    Highway engineering is an important discipline which comes under civil engineering it mainly deals with construction, maintenance and rehabilitation of roads, bridges and tunnels. India is approximately 3,060,500 square km in area and has a road network of over 3,315,231 kmThe road system carries 87% and 65% of passengers and freight respectively [2]. After India attained independence there was a spur growth in transportation sector due to industrialization, automation and urbanization. Because of which maintenance has to be given utmost importance in Highway maintenance.

    All structures are designed for a span of time which is called as service life over which it witnesses failure[8]. Survive life can be increased by maintenance of the structure. The effective maintenance of the pavement is done through pavement evaluation process. In this paper structural evaluation of flexible pavement is discussed.

    Structural evaluation of pavement could be defined as the measure of structural adequacy of the pavement. Pavement performance depends on the number of standard axle, drainage condition of pavement, temperature, soil present in subgrade, rainfall etc.

    Non-destructive method is widely used because of its advantage of leaving the pavement un effected after the test as compared to destructive tests. The popular methods used under non- destructive pavement analysis are Falling Weight Deflection method and Benkelman Beam Deflection method

    (BBD). Benkelman Beam Deflection method is discussed in detail in this paper.

  2. OBJECTIVES The main objectives of this paper are:

    • Asses the structural stability of pavement.

    • Estimate the overlay thickness.

  3. METHODOLOGY

    III.I: TRAFFIC DATA COLLECTION:

    Traffic data is collected by manual count method. Talley marks were used to represent the number of vehicles. For design purpose heavy commercial vehicles are to be considered. Initial traffic count is found out by this method which is then used for finding number of standard axels.

    III.II. DEFLECTION DATA COLLECTION

    To measure the rebound deflection using Benkelman Beam method we place the probe between the dual wheel arrangement of the trucks wheel. The standard load of the truck is to be of 8170 kg and a tyre pressure of 5.6 kg/cm2 is to be used. The probe is placed over the point where the deflection has to be measured. Before trials are taken it is properly calibrated on a hard levelled ground. A set of 3 points are to be taken namely initial, intermediate and final dial gauge reading (Do, Di and Df) at a distance of 2.7 m and 9m from the measuring points. 140 readings were taken at an interval of 50m in our case. Along with deflection, temperature was also noted down simultaneously.

      1. CORRECTIONS TO BE APPLIED:

        The various corrections to be applied include variation of temperature and variation of seasonal changes. Which is explained below

        1. CORRECTION FOR TEMPERATURE VARIATION:

          A pavements deflection depends on the temperature and it has been seen that the pavement layers vary according to variation in the temperature. Hence, we record the temperature along with the deflection measurement. Measurement was made by using short stem mercury thermometer. A hole of 45 millimeters deep and 10 mm in diameter was made. Glycerol was poured into this hole and the measurement were taken after an interval of 5 mins.

        2. CORRECTION FOR SEASONAL VARIATION

    Consideration of subgrade soil moisture content, average annual rainfall data and type of soil in the subgrade. Average rainfall data could be divided into heavy rainfall (annual

    rainfall >1300 mm) or less rainfall(annual rainfall

    <=1300mm). Subgrade soil can be classified into sandy soil, clayey soil with high plasticity (PI>15) and clayey soil with low plasticity (PI<=15) based on its plasticity index. The soil sample was scooped 15 cm below the subgrade for moisture content and plasticity index test. For this purpose a test pit was made in the shoulder.

  4. DATA COLLECTION AND OVERLAY DESIGN TRAFFIC DATA

    The traffic volume for the selected stretch was carried out

    on each stretches for each direction of traffic from starting

    point towards the ending point and vice versa. The traffic volume count is represented as vehicles per day. Traffic composition of the roads undertaken for surveys considers all types of traffic vehicles including motorized and non- motorized traffic. Motorized traffic consists of two wheelers, four wheelers, Buses, Two-axle and multi-axle trucks while a non-motorized vehicle consist of Bicycles and three wheelers. Survey was carried out from 6:00 AM to 6:00 PM. The volume was noted by counting the number of vehicles passing through the road section at every 1 hour intervals by manual counting

    TABLE 1: TRAFFIC DETAILS OF THE STUDY AREA

    Traffic studies

    Name of the work

    Overlay to Mayaganahalli Road to Sugganahalli Road from 0.55 km to 7.55 km (in Selected reaches) in Ramanagara taluk of Ramanagara District Via Dharapura

    Location

    Mayaganahalli

    Enumerator

    Narendra Kumar M, Chendan T M, Shivani Nagaraj, Sushmitha S

    Direction

    Up and down

    Date

    28/02/2019 TO 06/03/2019

    Sl.

    No.

    Vehicle type

    Day 1

    Day 2

    Day 3

    Day 4

    Day 5

    Day 6

    Day 7

    Total number of vehicles

    Daily average number of vehicles/ ADT

    Commercial Traffic

    1

    Car, Jeep, Van

    180

    192

    297

    206

    213

    197

    232

    1517

    217

    130

    2

    Auto Rickshaw

    203

    174

    283

    192

    200

    196

    236

    1484

    212

    3

    Scooters/Motorbikes

    1091

    811

    976

    869

    902

    912

    976

    6537

    934

    4

    Bus / Minibus

    24

    25

    30

    26

    27

    27

    29

    188

    27

    5

    trucks

    16

    28

    22

    29

    31

    33

    25

    184

    26

    6

    Tractors with trailer

    61

    38

    35

    42

    47

    38

    35

    296

    42

    7

    Tractors without trailer

    25

    42

    16

    45

    49

    49

    18

    244

    35

    8

    Cycles

    0

    0

    0

    0

    0

    0

    0

    0

    0

    9

    Cycle Rickshaw / Hand Cart

    0

    0

    0

    0

    0

    0

    0

    0

    0

    10

    Horse cart / Bullock Cart

    0

    0

    0

    0

    0

    0

    0

    0

    0

    Total non-motorised vehicle

    per day

    0

    IV.II. DEFLECTION DATA

    Deflection value Do (initial dial gauge reading), Di (intermediate dial gauge reading) and Df (final dial gauge reading) are collected in divisions for every 50 meter interval all through the stretch, simultaneously the temperature is recorded along with the collection of soil samples and rainfall data. The moisture content and plasticity index are determined later. All the readings are tabulated as shown in

    Table 1. Later all the necessary correction in each section are applied. Thus the Corrected Characteristic deflection is calculated in millimeters

    The correction for temperature is applied with the help of moisture content obtained. The moisture content obtained is 7.4% and the seasonal correction factor obtained was 1.037 by referring to fig 1.

    Fig 1: moisture content factor for sandy soil with annual rainfall <1300

    TABLE 2: PAVEMENT DEFLECTION DATA ALONG WITH THE SUITABLE CORRECTION APPLIED

    Name of Road :

    Overlay to Mayaganahalli Road to Sugganahalli Road from 0.55 km to 7.55 km in Ramanagara taluk of Ramanagara District Via Dharapura

    No. of Traffic Lane :

    2

    Whether temperature correction is to be applied:

    Yes

    Date of Observation :

    03-02-2019

    Annual Rainfall, mm:

    <1300

    CHAINAGE : FROM 0+550 TO 7+550

    Station

    Dial Gauge Reading

    Rebound Deflection D

    Pavement Temp.

    Temperature Corrected Deflection Dt

    Field Moisture

    Seasonal Correction Factor

    Moisture Corrected Deflection Dm

    Mean Deflection

    /km

    Standard Deviation

    Corrected Characteristic Deflection

    Do

    Di

    Df

    Mean

    S.D

    (Km)

    (Div)

    (Div)

    (Div)

    (mm)

    (OC)

    0.55

    100

    67

    65

    1.40

    32

    1.43

    7.30%

    1.037

    1.48

    1.67

    0.04

    1.70

    0.6

    100

    66

    64

    1.44

    33

    1.46

    7.30%

    1.037

    1.51

    0.03

    0.65

    100

    62

    60

    1.60

    32

    1.63

    7.30%

    1.037

    1.69

    0.00

    0.7

    100

    65

    63

    1.48

    34

    1.49

    7.30%

    1.037

    1.55

    0.01

    0.75

    100

    63

    61

    1.56

    32

    1.59

    7.30%

    1.037

    1.65

    0.00

    0.8

    100

    65

    63

    1.48

    33

    1.50

    7.30%

    1.037

    1.56

    0.01

    0.85

    100

    68

    66

    1.36

    32

    1.39

    7.30%

    1.037

    1.44

    0.05

    0.9

    100

    61

    59

    1.64

    35

    1.64

    7.30%

    1.037

    1.70

    0.00

    0.95

    100

    66

    64

    1.44

    31

    1.48

    7.30%

    1.037

    1.53

    0.02

    1

    100

    68

    66

    1.36

    32

    1.39

    7.30%

    1.037

    1.44

    0.05

    1.05

    100

    66

    64

    1.44

    32

    1.47

    7.30%

    1.037

    1.52

    0.02

    1.1

    100

    68

    66

    1.36

    33

    1.38

    7.30%

    1.037

    1.43

    0.06

    1.15

    100

    57

    55

    1.80

    32

    1.83

    7.30%

    1.037

    1.90

    0.05

    1.2

    100

    59

    57

    1.72

    32

    1.75

    7.30%

    1.037

    1.81

    0.02

    1.25

    100

    57

    55

    1.80

    33

    1.82

    7.30%

    1.037

    1.89

    0.05

    1.3

    100

    63

    61

    1.56

    32

    1.59

    7.30%

    1.037

    1.65

    0.00

    1.35

    100

    60

    58

    1.68

    34

    1.69

    7.30%

    1.037

    1.75

    0.01

    1.4

    100

    58

    56

    1.76

    32

    1.79

    7.30%

    1.037

    1.86

    0.04

    1.45

    100

    62

    60

    1.60

    34

    1.61

    7.30%

    1.037

    1.67

    0.00

    1.5

    100

    55

    53

    1.88

    32

    1.91

    7.30%

    1.037

    1.98

    0.10

    1.55

    100

    60

    58

    1.68

    32

    1.71

    7.30%

    1.037

    1.77

    0.01

    1.6

    100

    67

    65

    1.40

    33

    1.42

    7.30%

    1.037

    1.47

    0.04

    1.65

    100

    63

    61

    1.56

    32

    1.59

    7.30%

    1.037

    1.65

    0.00

    1.7

    100

    61

    59

    1.64

    32

    1.67

    7.30%

    1.037

    1.73

    0.26

    1.75

    100

    74

    72

    1.12

    35

    1.12

    7.30%

    1.037

    1.16

    0.01

    1.8

    100

    65

    63

    1.48

    32

    1.51

    7.30%

    1.037

    1.57

    0.37

    1.85

    100

    77

    75

    1.00

    33

    1.02

    7.30%

    1.037

    1.06

    0.46

    1.9

    100

    79

    77

    0.92

    32

    0.95

    7.30%

    1.037

    0.99

    0.35

    1.95

    100

    77

    75

    1.00

    31

    1.04

    7.30%

    1.037

    1.08

    0.36

    2

    100

    77

    75

    1.00

    32

    1.03

    7.30%

    1.037

    1.07

    0.37

    2.05

    100

    77

    75

    1.00

    33

    1.02

    7.30%

    1.037

    1.06

    0.05

    2.1

    100

    68

    66

    1.36

    32

    1.39

    7.30%

    1.037

    1.44

    0.03

    2.15

    100

    66

    64

    1.44

    34

    1.45

    7.30%

    1.037

    1.50

    0.31

    2.2

    100

    76

    74

    1.04

    32

    1.07

    7.30%

    1.037

    1.11

    0.52

    2.25

    100

    80

    78

    0.88

    31

    0.92

    7.30%

    1.037

    0.95

    0.04

    2.3

    100

    67

    65

    1.40

    32

    1.43

    7.30%

    1.037

    1.48

    0.05

    2.35

    100

    57

    55

    1.80

    33

    1.82

    7.30%

    1.037

    1.89

    0.00

    2.4

    100

    61

    59

    1.64

    32

    1.67

    7.30%

    1.037

    1.73

    0.14

    2.45

    100

    72

    70

    1.20

    31

    1.24

    7.30%

    1.037

    1.29

    0.31

    2.5

    100

    76

    74

    1.04

    32

    1.07

    7.30%

    1.037

    1.11

    0.05

    2.55

    100

    57

    55

    1.80

    33

    1.82

    7.30%

    1.037

    1.89

    0.36

    2.6

    100

    77

    75

    1.00

    32

    1.03

    7.30%

    1.037

    1.07

    0.03

    2.65

    100

    66

    64

    1.44

    34

    1.45

    7.30%

    1.037

    1.50

    0.27

    2.7

    100

    75

    73

    1.08

    32

    1.11

    7.30%

    1.037

    1.15

    0.45

    2.75

    100

    79

    77

    0.92

    31

    0.96

    7.30%

    1.037

    1.00

    0.12

    2.8

    100

    71

    69

    1.24

    32

    1.27

    7.30%

    1.037

    1.32

    0.28

    2.85

    100

    75

    73

    1.08

    33

    1.10

    7.30%

    1.037

    1.14

    0.19

    2.9

    100

    73

    71

    1.16

    32

    1.19

    7.30%

    1.037

    1.23

    0.06

    2.95

    100

    68

    66

    1.36

    33

    1.38

    7.30%

    1.037

    1.43

    0.02

    3

    100

    66

    64

    1.44

    31

    1.48

    7.30%

    1.037

    1.53

    0.27

    3.05

    100

    75

    73

    1.08

    32

    1.11

    7.30%

    1.037

    1.15

    0.01

    3.1

    100

    65

    63

    1.48

    32

    1.51

    7.30%

    1.037

    1.57

    0.21

    3.15

    100

    75

    73

    1.08

    32

    1.11

    7.30%

    1.037

    1.15

    0.04

    3.2

    100

    65

    63

    1.48

    33

    1.50

    7.30%

    1.037

    1.56

    0.00

    3.25

    100

    73

    71

    1.16

    34

    1.17

    7.30%

    1.037

    1.21

    0.02

    3.3

    100

    58

    56

    1.76

    32

    1.79

    7.30%

    1.037

    1.86

    0.02

    3.35

    100

    61

    59

    1.64

    34

    1.65

    7.30%

    1.037

    1.71

    0.01

    3.4

    100

    66

    64

    1.44

    32

    1.47

    7.30%

    1.037

    1.52

    0.00

    3.45

    100

    59

    57

    1.72

    32

    1.75

    7.30%

    1.037

    1.81

    0.00

    3.5

    100

    65

    63

    1.48

    31

    1.52

    7.30%

    1.037

    1.58

    0.10

    3.55

    100

    61

    59

    1.64

    34

    1.65

    7.30%

    1.037

    1.71

    0.05

    3.6

    100

    62

    60

    1.60

    31

    1.64

    7.30%

    1.037

    1.70

    0.22

    3.65

    100

    55

    53

    1.88

    32

    1.91

    7.30%

    1.037

    1.98

    0.07

    3.7

    100

    57

    55

    1.80

    32

    1.83

    7.30%

    1.037

    1.90

    0.04

    3.75

    100

    51

    49

    2.04

    33

    2.06

    7.30%

    1.037

    2.14

    0.05

    3.8

    100

    56

    54

    1.84

    32

    1.87

    7.30%

    1.037

    1.94

    0.07

    3.85

    100

    58

    56

    1.76

    31

    1.80

    7.30%

    1.037

    1.87

    0.04

    3.9

    100

    68

    66

    1.36

    32

    1.39

    7.30%

    1.037

    1.44

    0.05

    3.95

    100

    69

    67

    1.32

    32

    1.35

    7.30%

    1.037

    1.40

    0.07

    4

    100

    54

    52

    1.92

    32

    1.95

    7.30%

    1.037

    2.02

    0.12

    4.05

    100

    57

    55

    1.80

    34

    1.81

    7.30%

    1.037

    1.88

    0.04

    4.1

    100

    53

    51

    1.96

    32

    1.99

    7.30%

    1.037

    2.06

    0.15

    4.15

    100

    57

    55

    1.80

    31

    1.84

    7.30%

    1.037

    1.91

    0.06

    4.2

    100

    59

    57

    1.72

    32

    1.75

    7.30%

    1.037

    1.81

    0.02

    4.25

    100

    52

    50

    2.00

    32

    2.03

    7.30%

    1.037

    2.11

    0.19

    4.3

    100

    54

    52

    1.92

    33

    1.94

    7.30%

    1.037

    2.01

    0.12

    4.35

    100

    56

    54

    1.84

    31

    1.88

    7.30%

    1.037

    1.95

    0.08

    4.4

    100

    62

    60

    1.60

    32

    1.63

    7.30%

    1.037

    1.69

    0.00

    4.45

    100

    65

    63

    1.48

    31

    1.52

    7.30%

    1.037

    1.58

    0.01

    4.5

    100

    67

    65

    1.40

    32

    1.43

    7.30%

    1.037

    1.48

    0.04

    4.55

    100

    59

    57

    1.72

    32

    1.75

    7.30%

    1.037

    1.81

    0.02

    4.6

    100

    60

    58

    1.68

    33

    1.70

    7.30%

    1.037

    1.76

    0.01

    4.65

    100

    61

    59

    1.64

    34

    1.65

    7.30%

    1.037

    1.71

    0.00

    4.7

    100

    63

    61

    1.56

    32

    1.59

    7.30%

    1.037

    1.65

    0.00

    4.75

    100

    55

    53

    1.88

    31

    1.92

    7.30%

    1.037

    1.99

    0.10

    4.8

    100

    57

    55

    1.80

    32

    1.83

    7.30%

    1.037

    1.90

    0.05

    4.85

    100

    58

    56

    1.76

    32

    1.79

    7.30%

    1.037

    1.86

    0.04

    4.9

    100

    59

    57

    1.72

    33

    1.74

    7.30%

    1.037

    1.80

    0.02

    4.95

    100

    63

    61

    1.56

    34

    1.57

    7.30%

    1.037

    1.63

    0.00

    5

    100

    64

    62

    1.52

    32

    1.55

    7.30%

    1.037

    1.61

    0.00

    5.05

    100

    66

    64

    1.44

    31

    1.48

    7.30%

    1.037

    1.53

    0.02

    5.1

    100

    70

    68

    1.28

    32

    1.31

    7.30%

    1.037

    1.36

    0.10

    5.15

    100

    71

    69

    1.24

    31

    1.28

    7.30%

    1.037

    1.33

    0.12

    5.2

    100

    72

    70

    1.20

    33

    1.22

    7.30%

    1.037

    1.27

    0.16

    5.25

    100

    52

    50

    2.00

    34

    2.01

    7.30%

    1.037

    2.08

    0.17

    5.3

    100

    53

    51

    1.96

    32

    1.99

    7.30%

    1.037

    2.06

    0.15

    5.35

    100

    55

    53

    1.88

    31

    1.92

    7.30%

    1.037

    1.99

    0.10

    5.4

    100

    56

    54

    1.84

    33

    1.86

    7.30%

    1.037

    1.93

    0.07

    5.45

    100

    57

    55

    1.80

    32

    1.83

    7.30%

    1.037

    1.90

    0.05

    5.5

    100

    58

    56

    1.76

    34

    1.77

    7.30%

    1.037

    1.84

    0.03

    5.55

    100

    53

    51

    1.96

    32

    1.99

    7.30%

    1.037

    2.06

    0.15

    5.6

    100

    54

    52

    1.92

    33

    1.94

    7.30%

    1.037

    2.01

    0.12

    5.65

    100

    61

    59

    1.64

    32

    1.67

    7.30%

    1.037

    1.73

    0.00

    5.7

    100

    63

    61

    1.56

    31

    1.60

    7.30%

    1.037

    1.66

    0.00

    5.75

    100

    64

    62

    1.52

    32

    1.55

    7.30%

    1.037

    1.61

    0.00

    5.8

    100

    66

    64

    1.44

    33

    1.46

    7.30%

    1.037

    1.51

    0.03

    5.85

    100

    67

    65

    1.40

    32

    1.43

    7.30%

    1.037

    1.48

    0.04

    5.9

    100

    68

    66

    1.36

    33

    1.38

    7.30%

    1.037

    1.43

    0.06

    5.95

    100

    70

    68

    1.28

    32

    1.31

    7.30%

    1.037

    1.36

    0.10

    6

    100

    71

    69

    1.24

    34

    1.25

    7.30%

    1.037

    1.30

    0.14

    6.05

    100

    52

    50

    2.00

    32

    2.03

    7.30%

    1.037

    2.11

    0.19

    6.1

    100

    53

    51

    1.96

    31

    2.00

    7.30%

    1.037

    2.07

    0.16

    6.15

    100

    54

    52

    1.92

    32

    1.95

    7.30%

    1.037

    2.02

    0.12

    6.2

    100

    55

    53

    1.88

    33

    1.90

    7.30%

    1.037

    1.97

    0.09

    6.25

    100

    57

    55

    1.80

    32

    1.83

    7.30%

    1.037

    1.90

    0.05

    6.3

    100

    58

    56

    1.76

    34

    1.77

    7.30%

    1.037

    1.84

    0.03

    6.35

    100

    59

    57

    1.72

    32

    1.75

    7.30%

    1.037

    1.81

    0.02

    6.4

    100

    61

    59

    1.64

    31

    1.68

    7.30%

    1.037

    1.74

    0.00

    6.45

    100

    63

    61

    1.56

    32

    1.59

    7.30%

    1.037

    1.65

    0.00

    6.5

    100

    64

    62

    1.52

    33

    1.54

    7.30%

    1.037

    1.60

    0.00

    6.55

    100

    66

    64

    1.44

    32

    1.47

    7.30%

    1.037

    1.52

    0.02

    6.6

    100

    55

    53

    1.88

    31

    1.92

    7.30%

    1.037

    1.99

    0.10

    6.65

    100

    57

    55

    1.80

    32

    1.83

    7.30%

    1.037

    1.90

    0.05

    6.7

    100

    59

    57

    1.72

    32

    1.75

    7.30%

    1.037

    1.81

    0.02

    6.75

    100

    60

    58

    1.68

    33

    1.70

    7.30%

    1.037

    1.76

    0.01

    6.8

    100

    61

    59

    1.64

    32

    1.67

    7.30%

    1.037

    1.73

    0.00

    6.85

    100

    62

    60

    1.60

    31

    1.64

    7.30%

    1.037

    1.70

    0.00

    6.9

    100

    63

    61

    1.56

    32

    1.59

    7.30%

    1.037

    1.65

    0.00

    6.95

    100

    52

    50

    2.00

    33

    2.02

    7.30%

    1.037

    2.09

    0.18

    7

    100

    53

    51

    1.96

    32

    1.99

    7.30%

    1.037

    2.06

    0.15

    7.05

    100

    54

    52

    1.92

    34

    1.93

    7.30%

    1.037

    2.00

    0.11

    7.1

    100

    55

    53

    1.88

    32

    1.91

    7.30%

    1.037

    1.98

    0.10

    7.15

    100

    58

    56

    1.76

    32

    1.79

    7.30%

    1.037

    1.86

    0.04

    7.2

    100

    59

    57

    1.72

    31

    1.76

    7.30%

    1.037

    1.83

    0.03

    7.25

    100

    60

    58

    1.68

    32

    1.71

    7.30%

    1.037

    1.77

    0.01

    7.3

    100

    52

    50

    2.00

    33

    2.02

    7.30%

    1.037

    2.09

    0.18

    7.35

    100

    54

    52

    1.92

    32

    1.95

    7.30%

    1.037

    2.02

    0.12

    7.4

    100

    55

    53

    1.88

    31

    1.92

    7.30%

    1.037

    1.99

    0.10

    7.45

    100

    59

    57

    1.72

    32

    1.75

    7.30%

    1.037

    1.81

    0.02

    7.5

    100

    58

    56

    1.76

    32

    1.79

    7.30%

    1.037

    1.86

    0.04

    7.55

    100

    54

    52

    1.92

    32

    1.95

    7.30%

    1.037

    2.02

    0.12

    COMPUTATION OF DESIGN TRAFFIC

    The design traffic is considered in terms of the cumulative number of standard axles to be carried during the design life of the overlay. It is given by the formula mentioned below

    Ns = 365*A*[(1 + r)X 1] * F

    r

    where,

    Ns = The cumulative number of standard axles to be catered for in the design

    A = Initial traffic, in the year of completion of construction, in terms of the number of commercial vehicles per day duly modified to account for lane distribution = 130 cv/day

    r = Annual growth rate of commercial vehicles = 7.5% X = Design life in years = 10 years

    F = Vehicle damage factor (number of standard axles per commercial vehicle) = 1.5

    Thus cumulative axle load, Ns = 1.0069 million standard axle

    DESIGN OF OVERLAY

    As per Fig. 2; for the selected stretch of 7.00 km, the characteristic deflection of 1.70 mm and the design traffic of 1.0069 million standard axle (msa), an overlay of 25 mm is to be provided. But as per the guidelines of IRC, an overlay of 50 mm BM and 40 mm BC is recommended.

    Fig 2: Overlay Thickness Design Curves

  5. CONCLUSION

    Structural evaluation of pavement is carried out to determine the capacity of the pavement to withstand future traffic load. The experimental results of the project will help in studying the existing condition of the pavement in terms of structural adequacy.

    Thus from clause 7.5 of IRC 81, to serve the structural inadequacy it is recommended to provide 50 mm BM and a surface course of 40 mm BC.

  6. REFERNCES

  1. IRC: 81-1997 Guidelines for Strengthening of Flexible pavement using Benkelman Beam Deflection Technique. (1st Revision), Indian Roads Congress, New Delhi.

  2. Dr. Umesh Sharma, Non-Destructive Evaluation of an Internal Road of Chandigarh – A Critical Study International Conference on Biological, Civil and Environmental Engineering (BCEE- 2014) March 17-18, 2014 Dubai (UAE).

  3. Rokade S, Agarwal P. K, Srivastava R.,Study On Performance Of Flexible Highway pavements, Ijaet/ Vol.01/ Issue-03/ Oct- Dec-2010, PP 312-338.

  4. Mr. Jay J. Parekh, Dr. Yogesh U. Shah, Functional and Structural Evaluation of Urban Road Sections in Rajkot City", International Journal of Scientific Development and Research, Volume 1, Issue 5, (May, 2016).

  5. Bhatt Mayank G, Amit Vankar, Zala L.B. On Structural Evaluation using Benkelman Beam Deflection Technique and Rehabilitation of flexible pavement for State Highway 188, Journal of International Academic Research for Multidisciplinary, 11(4)2013, 452 462.

  6. S.K. Khanna, C.E.G Justo, A. Veeraragavan, Highway Engineering, Nem Chand and Brothers, Roorkee, Tenth Edition, 2015.

  7. B. Subramanyam, Aravind S, Prasanna Kumar R, functional and Structural evaluation of a Road Pavement. International Journal of Civil Engineering and technology, 8(8), 2017, pp 1299-1305.

  8. A case study on south arterial road, Yogyakarta by Untung Rusmanto, Syafii, and Dewi Handayani Citation: AIP Conference Proceedings 1977, 040014 (2018); doi: 10.1063/1.5042984.

  9. IRC 37 2018- Guidelines for the design of flexible pavements.

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