MoRD Specifications and Manual - Rural Road Construction PDF

D.V .Bhavanna Rao M.Tech., F.I.E., Retired R&B Chief Engineer E-mail: [email protected] Phone: +919494440202

for all my presentations, please visit http://aproadbuildqa.blogspot.com

Important Publications for Rural Roads 1.Specifications for Rural Roads, MORD (2004). 2.Rural Roads Manual IRC:SP:20-2002. 3. MORD Quality Assurance Handbook for Rural Roads Volume I and II :2007 4.Hill Road Manual: IRC:SP:48-1998. 5.IRC:SP: 72-2007: Guidelines for design of flexible pavements for low volume Rural Roads 6. IRC:SP: 62-2004 Guidelines for Design of Rigid Pavements for Rural Roads

300 Earth works 301 Embankment construction 302 Earth work in cutting 303 Subgrade construction 304 Rock cutting 305 Excavation for structures 306 Flyash Embankment construction 307 Surface drains 308 Soil erosion and sedimentation control 309 Turfing with sods 310 Seeding and mulching

400 Granular Sub-bases, Bases & surfacings 401 Granular Sub - Base 402 Gravel/Soil – Aggregates base and surface course 403 Lime treated soil for improved Sub – Grade / sub base 404 Cement treated Soil sub-base/ base 405 Water Bound macadam sub-base/ bases/surfacing 406 Wet Mix Macadam base 407 Shoulder construction 408 Local materials for road construction 409 Lime – Flyash stabilised soil sub-base 410 Industrial wastes for road construction 411 Crusher – Run macadam base 412 Brick soling 413 Stone set pavement

500 Bituminous costruction 501 Preparation of surface. 502 Prime coat over Granular Base 503 Tack coat 504 Bituminous Macadam 505 Built-up spray grout 506 Modified penetration macadam 507 Surface dressing 508 20mm Thick premix carpet 509 Mix seal surfacing 510 Seal coat 511 Supply of stone aggregates for pavement courses 512 Modified bitumen

Other Important Sections in MORD Specifications 200 Site Clearance 600 Brickwork for Structures 700 Stone masonry for Structures 800 Concrete for Structures 900 Formwork and surface finish for structures 1000 Steel reinforcement 1100 Pipe culverts 1200 RCC slab culverts and minor bridges 1400 Cement Concrete Causeways 1500 Cement Concrete Pavement 1600 Hill Road Construction 1800 Quality Control 1900 Maintenance

Important Sections in IRC:SP:20-2002 Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter Chapter

1: Planning and Alignment 2: Geometric Design Standards 3: Climate and Environment 4: Road Materials 5: Pavement design 6: Road Drainage 7: Culverts and Small Bridges 8: Construction and Specifications 9: Use of Waste materials 10: Quality Control in Construction 11: Maintenance 12: Souces of Finance

Typical cross section in plain and rolling terrain

shoulder

Base Sub base eeeeEeeee Sub-Grade (300mm)

shoulder

Embankment

Typical Pavement Cross Section

Pavement thickness chart as per IRC: SP 20 2002

Pavement thickness as per IRC: SP 20 2002 CBR

2%

3%

4%

5%

6%

Crust

0 to 15 CVPD

15 to 45 CVPD

45 to 150 CVPD

150 to 450 CVPD

Base

150

150

225

225

Sub base

275

365

370

455

Base

150

150

150

225

Sub base

200

265

330

320

Base

150

150

150

150

Sub base

125

200

260

315

Base

150

150

150

150

Sub base

100

165

210

260

Base

150

150

150

150

Sub base

60

115

150

175

Pavement thickness as per IRC: SP 20 2002 CBR

7

10%

15%

20%

Crust

0 to 15 CVPD

15 to 45 CVPD

45 to 150 CVPD

150 to 450 CVPD

Base

150

150

150

150

Sub base

60

115

150

175

Base

150

150

150

150

Sub base

30

70

85

125

Base

150

150

150

150

Sub base

nil

30

50

75

Base

150

150

150

150

Sub base

nil

nil

30

50

IRC: SP 72 – 2007, Pavement Design Catalogue. CBR = 2% Cumulative ESAL applications

Bituminous Surface treated WBM/CRMB

Base of gravel, WBM, CRMB of CBR not less than 100%

10,000 to 30,000

Nil

nil

200

nil

100

30,000 to 60,000

75

nil

150

nil

100

60,000 to 1,00,000

75

100

nil

100

100

1,00,000 to 2,00,000

75

100

nil

100

150

2,00,000 to 3,00,000

75

100

nil

150

150

3,00,000 to 6,00,000

75

100

nil

225

150

6,00,000 to10,00,000

75

150

nil

200

225

Gravel Base of CBR not less than 80%

Granular Sub Base of CBR not less than 20%

Modified soil or sub grade of CBR not less than 10%

T04%IRC: SP 72 – 2007, Pavement Design Catalogue. CBR = 3 to 4%

Cumulative ESAL applications



10,000 to 30,000

Nil

nil

200

nil

nil

30,000 to 60,000

nil

nil

275

nil

nil

60,000 to 1,00,000

75

100

nil

150

nil

1,00,000 to 2,00,000

75

100

nil

100

100

2,00,000 to 3,00,000

75

100

nil

100

150

3,00,000 to 6,00,000

75

150

nil

100

150

6,00,000 to10,00,000

75

150

nil

150

150








10,000 to 30,000

Nil

nil

175

nil

nil

30,000 to 60,000

nil

nil

250

nil

nil

60,000 to 1,00,000

nil

nil

275

nil

nil

1,00,000 to 2,00,000

75

100

nil

125

nil

2,00,000 to 3,00,000

75

100

nil

150

nil

3,00,000 to 6,00,000

75

100

nil

100

100

6,00,000 to10,00,000

75

150

nil

100

100








10,000 to 30,000

Nil

nil

150

nil

nil

30,000 to 60,000

nil

nil

175

nil

nil

60,000 to 1,00,000

nil

nil

225

nil

nil

1,00,000 to 2,00,000

75

100

nil

100

nil

2,00,000 to 3,00,000

75

100

nil

125

nil

3,00,000 to 6,00,000

75

100

nil

150

nil

6,00,000 to10,00,000

75

150

nil

150

nil








10,000 to 30,000

Nil

nil

125

nil

nil

30,000 to 60,000

nil

nil

150

nil

nil

60,000 to 1,00,000

nil

nil

175

nil

nil

1,00,000 to 2,00,000

75

150

nil

nil

nil

2,00,000 to 3,00,000

75

100

nil

100

nil

3,00,000 to 6,00,000

75

100

nil

125

nil

6,00,000 to10,00,000

75

150

nil

125

nil




Embankment Construction 1.Embankment with natural earth

2. Embankment with Coal Ash a. Fly Ash b. Pond Ash c. Bottom Ash

Sub Grade Construction 1.Sub Grade with natural earth 2. Sub Grade with stabilised earth a. Stabilisation with sand and lime b. Stabilisation with coal ash c. Stabilisation with soft aggregates d. Stabilisation with gravel / moorum e. Stabilisation with cement

The following types of material shall be considered unsuitable for embankment, sub grade and shoulders: (i) Material from swamps, marshes and bogs (ii) Peat, log, stump and perishable material; soil classified as OL, OI, OH or Pt as per IS:1498. (iii) Materials susceptible to spontaneous combustion. (iv) Clay having liquid limit exceeding 70 and plasticity index exceeding 45. (v) Material with salts resulting in leaching action e.g. Soils of pH > 8.5). (vi) Expansive clay with free swelling index exceeding 50 per cent (vii) Materials in a frozen condition. (viii) Fill materials with a soluble sulphate content exceeding 1.9 gm of sulphate, (expressed as SO3) per litre, if deposited within 500 mm or other distance described in the Contract, of concrete, cement bound materials or other cementitious materials forming part of permanent works. (ix) Material with a total sulphate content (expressed as SO3) exceeding 0.5 per cent by mass, if deposited within 500 mm or other distance described in the Contract, of metallic items forming part of permanent works

MORD 301 Embankment Requirements  Liquid limit < 70%, Plasticity Index< 45%,FSI < 50%  MDD(min):1.44 g/cc up to 3m height and 1.52vg/cc for

embankment > 3m height.  In case of fly Ash minimum MDD is reduced to 0.9 g/cc as per IRC Special Publication No.58  Breaking clods: 75mm maximum  Moisture content: +1% or -2% of OMC for sandy / silty soils

and OMC to OMC + 2% for clayey / BC soils  Maximum layer thickness: 200mm (vibratory roller) or 150mm in case of smooth wheeled roller  Trimming: additional width of 0.6m on either side  Relative compaction: 97%

MORD 303 Sub Grade Requirements Existing sub grade: If sub grade CBR is less than 2%, a capping layer of 100mm thick with 10% CBR soil is to be provided and a CBR of 2% is to be taken for crust design 

New sub grade and Shoulders: MDD (min) is 1.65 g/cc Moisture content: +1% or -2% of OMC Relative Compaction: 100%

DO’s

Don’ts

1. Discourage borrow pits along the road; where permitted, ridges of minimum 8 m width should be left at intervals not exceeding 300 m. Small drains should be cut through the ridges to facilitate drainage. 2. The depth of borrow pits should be so regulated that their bottom does not cut an imaginary line having a slope of 1 vertical to 4 horizontal projected from the edge of the final section of the bank, the maximum depth in any case being limited to 1.0 m. 3. Do maintain a camber/ cross fall of 4 percent during construction for effective drainage and prevention of Ponding of water. 4. The area of the embankment foundation should be kept dry. Test the material (soil) for its suitability for use in the embankment at least seven days before commencement of earthwork. Tests should include soil. classification test data and data regarding maximum dry density, OMC, and CBR (soaked and un soaked). 5. For widening of existing embankment start earth work from toe line.

1. Do not allow borrow pits within a distance equal to the height of the embankment subject to a minimum of 1.5 m from the toe of the road embankment. 2. Do not allow borrow pits within 800 m of towns or villages. 3. Do not use unsuitable material for embankment construction. 4. Do not allow construction or other vehicular traffic over the prepared surface of embankment/ sub-grade. 5. Do not place successive layers of embankment until the previous layer has been thoroughly compacted and duly approved by Engineer. 6. Do not allow any damage to works, crops or other property while discharging stagnant water found in embankment foundation. 7. Do not allow dumping of earth from top to widen an existing embankment.

Appropriate Technology and machinary For Earthwork and Subgrade Construction 1. For clearing, grubbing and excavation : Rippers towed by agricultural tractor 2. For hauling of earth : Agricultural tractor-trailer 3. For spreading of soil in layers : Spreading blades attached to agricultural tractor 4. For adding water : Water Bowser towed by agricultural tractor 5. For mixing of soil with water : Agricultural tractortowed disc harrows 6. For compaction in earthwork and : 80-100 kN static smoothsubgrade construction wheeled road roller for compacted thickness of 100 mm.

Loading of embankment material at borrow source

Dumping of embankment material

Preparation of embankment

Rapid Determination of Moisture Content from Gas Pressure developed by the Reaction of Calcium Carbide with the Free Water of the Soil

Loose earth shall not be allowed to soak.

watering of embankment material

Field density test for embankment layers

Dumping of sub grade material

Moisture content versus Dry density relationship for a soil of poorly graded sands with little or no fines SP 1.86 1.84 1.82

Moisture Content %

Dry Density g/cc

3.12

1.74

4.3

1.77

5.41

1.79

7.3

1.85

1.74

12.85

1.757

1.72

15.71

1.69

1.7

1.8 1.78

Se…

1.76

1.68

0

OMC = 7.3 % MDD = 1.85 g/cc

5

10

15

20

grading of sub grade material

Rolling of sub grade material

Field density testing of sub grade material

Fly ash for road embankment  Ideally suited as backfill material for urban/ industrial areas and areas with weak sub soils  Higher shear strength leads to greater stability  Design is similar to earth embankments  Intermediate soil layers for ease of construction and to provide confinement  Side slope erosion needs to be controlled by providing soil cover  Can be compacted under inclement weather conditions  15 to 20 per cent savings in construction cost depending on lead distance

Fly ash for road embankment Earth Cover

Earth Cover Bottom ash or Pond ash

Typical cross section of fly ash road embankment

Approach embankment for second Nizamuddin bridge at Delhi     

Length of embankment - 1.8 km Height varies from 6 to 9 m Ash utilised - 1,50,000 cubic metre Embankment opened to traffic in 1998 Instrumentation installed in the embankment showed very good performance  Approximate savings due to usage of fly ash is about Rs.1.00 Crore

Approach embankment for second Nizamuddin bridge at Delhi

MORD Specification 401 Granular Sub Base Minimum CBR = 20% (on economical basis,15% may be permitted by competent authority) Material in mix passing 425 micron sieve shall have Liquid limit less than 25% Plasticity index less than 6% Material passing 75 micron sieve shall be less than 10%. (less than 5% on clayey sub grades) Material in the mix shall satisfy specified grading Wet Aggregate Impact value shall be less than 50% Layer thickness: 100 mm compacted with smooth wheeled roller 225 mm compacted with vibratory roller Moisture content: + 2% to – 2% of OMC Relative compaction: 100% ( Standard Procter’s test)

Table 400-1, MORD Specifications for Rural Roads Grading for Granular Sub-Base materials Percent by weight passing through the IS sieve IS Sieve Designation Grading I Grading II Grading III

75.0 mm

100

53.0 mm

--

--

100

26.5 mm

55-75

50-80

100

4.75 mm

10-30

15-35

25-45

0.075 mm

< 10

< 10

< 10

1) Liquid limitt < 25% and plasticity index < 6% 2) On clayey sub grade % passing on 75 micron sieve shall not exceed 5% 3) Wet Aggregate Impact Value shall not exceed 50%

Methodology 1. Obtain materials from approved sources. The material should be natural sand, moorum, gravel,crushed stone, crushed slag, brick metal, kankar or a combination thereof and it shall conform to grading and physical requirements indicated in Table 401.1 2. The sub-base material should be spread in layers not exceeding 100 mm compacted thickness. If suitable vibratory rollers are available, the compacted thickness of layer can be upto a maximum of 225 mm. 3.When the sub-base material consists of a combination of materials, mixing shall be done mechanically by the mix-in-place method, except for small sized jobs. 4. Each layer shall be uniformly spread and thoroughly compacted. Spreading and compaction shall be carried out as per Clause 401.4.2 of the MORD Specifications. 5. Approval of the Engineer should be obtained for each layer. Such an approval would require surface level and compaction control tests. 6. The earthen shoulders should be constructed simultaneously with the sub-base construction.

DO’s

1. Ensure uniform mixing of GSB material and water by mechanical means like tractor towed implements. 2. Ensure that on clayey sub grades, the percent fines passing 75 micron in the GSB material do not exceed 5 percent. 3. Do provide aggregate plugs at the exposed edges of GSB where extended over the full formation width. 4. Look for soft patches, if any, and rectify them by removing or adding fresh material and compacting the same thoroughly.

Don’ts

1. Do not permit organic or other deleterious materials. 2. Do not use materials, which do not conform to the specified requirements, shall not be used. 3. Do not allow rejected material to remain at site to prevent its reuse. The rejected material shall be marked with lime.

Preparation of Granular Sub base mix using 45% gravelly soil, 35% sand and 20% grade III metal

Construction of Granular Sub base mix using 45% gravelly soil, 35% sand and 20% grade III metal

Gravel associated GSB (mixture of gravelly soil (45%), metal (20%) and sand (35%) is creating lot of problems in execution during rains. It is preferable to opt for GSB without any gravelly soil

Mud

pumping

Definition of sand and gravel as per Code IS: 1490 – 1987 Sand and gravel are defined as Cohesion less aggregates of angular, sub-angular, subrounded, rounded, flaky or flat fragments of more or less unaltered rocks or minerals. According to the system, gravel is the fraction of the material between 80mm IS sieve size and 4.75mm IS sieve size. Sand is a fraction of the material between 4.75mm IS sieve size and 75 micron IS sieve size.

River gravel along Wankidi vaagu across which is being constructed in km 17/10 of Wankidi Kagaznagar in Adilabad District. This type of material satisfies gravel requirements as per IS code or MORT&H specifications. AIV = 14%. It satisfies grading III of table 400 – 2 for Granular Sub Base

Layer of adsorbed water surrounding a clay particle. Sliding of such particles over one another results in plasticity

Position after 24 hours of adding water

Natural gravelly soil LL = 38%, PI = 18%

Total Absorption of particles indicate the presence of negative charged particles in the gravelly soil. It indicates high PI and LL values. It proves that the above sample is earthen material only but not gravel or moorum. Use of such soil presuming it as gravel is causing damage and poor condition of Village Roads, Major District Roads, State Highways and National Highways. Highway Engineers must be able to differentiate between earth and gravel

GSB using crushed quarry spoils and granite for Pushkaram work in Narsapur in WG Dt. Similar mix is being used as GSB in NHAI works. This type of mix eliminates all problems associated with gravel combinations

Another view of GSB without gravel in Narsapur Drainage: Excellent, CBR: more than 60%

GSB with gravelly soil (45%), stone dust (35%) and metal (20%) also caused problems when executed during rainy season

GSB using gravel with some stone content being done in 4-laning of NH5 in Srikakulam District. Here, it contains lot of fines with high Plasticity Index value. It may give the required CBR but fails in plasticity

GSB with HBG materials as per Grading III of MORD table 400-1. Stone dust and 6mm to 10mm chips are mixed to satisfy the grading. It is producing CBR of more than 30%

Moisture content versus Dry density relationship for GSB with HBG crushed aggregates confirming to Grading III of table 400-2 2.28

Moisture Content %

Dry Density g/cc

2.87

2.14

3.73

2.17

2.26

2.24

2.22

2.2

5.4

2.22

7.69

2.26

9.07

2.165

2.16

10.39

2.11

2.14

Series1

2.18

2.12

OMC = 7.69 % MDD = 2.26 g/cc

2.1 0

2

4

6

8

10

12

GSB using HBG materials as per grading III of MORD table 400-1. Stone dust, 6mm chips and 10 mm chips are used. It is good for drainage and produce CBR above 30%

GSB using HBG materials as per MORD grading III of table 400-1. Stone dust, 6mm chips and 10 mm chips are used. It is good for drainage and produce CBR above 30%. NABARD work: Narakoduru Anantavarappadu road, Guntur District

GSB using HBG materials as per grading III of MORD table 400-1. Stone dust, 6mm chips and 10 mm chips are used. It is good for drainage and produce CBR above 30% Machavaram village limits in Guntur district

GSB with alternate materials WBM with grade I HOG metal without blindage. This is an excellent GSB option. It gives very high CBR values(>50%) and also serves as a good drainage layer

MORD Specifications 402: Gravel/ Soil-Aggregate 403: Lime treated soil for improved sub grade/ sub-base 404: Cement treated soil sub-base/ base 408: Local materials for road construction

409: Lime-Fly ash stabilised soil sub-base 410: Industrial Wastes for Road Construction

MORD 408 Local materials for Road Construction Table 400–13: Manner of using local aggregates in rural road works State of occurrence of material

Manner of using in pavement crust

Test/ quality requirements

In block or large discrete particles such as kankar, laterite, dhandla etc.

As WBM without screenings/ binder after breaking into sizes

Wet AIV ≤ 50%, 40% and 30% for sub-base, base and surfacing

as granular layer for sub-base or base or surfacing

PI: 4 to 10 for surfacing, PI< 6 for lower courses. Soaked CBR for strength

As discrete particles mixed with appreciable Directly as soil-gravel amount of soil such as soil mix for sub-base or gravel mixtures, quarry base or surfacing wastes etc

Material well graded. Other requirements as above

Graded form without appreciable amount of soil, such as naturally occurring soils

Base Requirements as per IRC: SP 20 - 2002 Minimum thickness of base: 150mm Requirements of Base Courses: Densely Compacted layers with hard, durable, angular and non-plastic materials capable of resisting heavy loads, resistance to lateral movement and transmission of reduced uniform load distribution to sub base layers

Base Courses: Wet Mix Macadam Crusher Run Macadam Water Bound Macadam Dry Lean Concrete Requirements of Base Courses: Densely Compacted layers with hard, durable, angular and non-plastic materials capable of resisting heavy loads, resistance to lateral movement and transmission of reduced uniform load distribution to sub base layers

WMM

WBM with gravelly soil blindage

WBM with screenings and binder

CRM

Sizes Of Coarse Aggregates As Per Apss Table 1501-A Normal Size

Wholly passing through sieve of square mesh of size

Wholly retained an a sieve of square mesh of size

80 mm

100 mm

63 mm

63 mm

80 mm

50 mm

50 mm

63 mm

40 mm

40 mm

50 mm

25 mm

25 mm

40 mm

20 mm

20 mm

25 mm

12.5 mm

12.5 mm

20 mm

10 mm

10 mm

12.5 mm

6.3 mm

6.3 mm

10 mm

2.36 mm

Table 500-17, MORD size requirements for coarse stone aggregates Nominal size of aggregate

Sieve size through which Sieve size on which aggregates wholly pass aggregates wholly retained

75mm

106mm

63mm

63mm

90mm

53mm

45mm

53mm

26.5mm

26.5mm

45mm

22.4mm

22.4mm

26.5mm

13.2mm

13.2mm

22.4mm

11.2mm

11.2mm

13.2mm

6.7mm

6.7mm

11.2mm

5.6mm

MORD Table 400-7, Physical Requirements of Coarse Aggregates for WBM Test Sub-base Base Surfacing AIV < 50% < 40% < 30% FIV < 30% < 25% < 20% Soundness Test when water absrption > 2% Loss with sodium sulphate < 12% Loss with magnesium < 18% sulphate For Screenings: LL < 20%, PI < 6% and % passing 75 micron sieve < 10% (405.2.8) For binder: PI < 6% for sub base and base. PI shall be from 4 to 10% for binder for srfacing (405.2.9)

Coarse Aggregates: Gr-I to Gr-III, Screenings: Type-A: 6mm and 10mm, Type-B: Stone Dust Binder: Stone Dust. Gravel for WBM as wearing course  Process of WBM

Spreading Metal > Sectioning and Dry Rolling > Light Sprinkling of Water > rolling > Application of Screenings > Brooming > Rolling > Watering & Sweeping > Rolling > Application of Binder > Sprinkling of Water & Sweeping > Rolling > Setting and Drying

DO’s

Don’ts

1. Check aggregates for Soundness test when water absorption is more than 2% 2. Soft aggregate should be tested for wet aggregate impact value. 3. Construct shoulders simultaneously along with WBM layers. 4. Use inverted choke over fine grained soil sub-grade. 5. Remove BT surface before WBM is laid on an existing black top road. 6. Remove defective macadam to full depth and replace by fresh material and re-compact.

1. Do not use any material derived from rocks e.g. phyllites, shales or slates. 2. Do not use local soil and clayey material as screenings or binding material unless it meats the requirements of PI mentioned 3. Do not use binding material if screenings are of crushable type. 4. Do not spread coarse aggregate more than 3 days in advance of any subsequent operations. 5. Do not roll if sub-grade is soft or yielding or causes a wave like motion while rolling. 6. Do not lay WBM layer on lime treated sub-base until it has attained its strength. 7. Do not use screenings to make up depressions. 8. Do not allow traffic till WBM is fully set.

Grade I HBG metal as per table 400 - 8

Cumulativ % IS Sieve passing

specified

125mm

100

100

90mm

92

90 - 100

63mm

45

25 - 60

45mm

8

0 - 15

22.4mm

3

0-5

Grade II HBG metal as per table 400 - 8


specified

90mm

100

100

63mm

94

90 - 100

53mm

50

25 - 75

45mm

7

0 - 15

22.4mm

3

0-5

Grade III HBG metal as per table 400 - 8


specified

63mm

100

100

53mm

97

95 - 100

45mm

80

65 - 90

22.4mm

8

0 - 10

11.2mm

2

0-5

MORD Table 400 - 9

Type of screenings Type A 13.2mm (6mm & 10mm chips) Type B 11.2mm (stone dust)

Type A screenings

IS Sieve 13.2mm 11.2mm 5.6mm 180 micron 11.2mm 5.6mm 180 micron

% passing 100 95-100 15-35 0-5 100 90-100 15-35

Type B screenings or binder

Sieve Analysis of stone dust with type B screenings sieve set Percent passing Sample 1

Sample 2

Sample 3

Specified passing for Type B Screenings

11.2m m

100

100

100

100

5.6mm

96.12

98.62

99.54

90 - 100

180 micron

24.52

17.83

20.82

15 - 35

IS Sieve

Stone screenings type

quantity/10Sqm

Binder per 10SqM

Gr I - 133/100mm

type A

0.27 to 0.3 cum

0.08 to 0.10 cum

Gr II – 100/75mm

type A

0.12 to 0.15 cum

-do-

type B

0.20 to 0.22 cum

Gr III 100/75mm

type B

0.18 to 0.21 cum

WBM

0.06 to 0.09 cum

Item

Coarse Aggregates

Type A screenings (6mm)

Type B screenings (dust)

Binder (dust)

Grad I WBM

1.21 cum

0.27 cum

nil

0.08 cum

Grade II WBM with type A screenings

0.91 cum

0.12 cum

nil

0.06 cum

Grade II WBM with type B screenings

0.91 cum

nil

0.20 cum

0.06 cum

Grade III WBM

0.91 cum

nil

0.18 cum

0.06 cum

Incorrect practice of WBM with gravelly soil blindage adopted over the years.

Spreading of metal using templates placed across the road about 6m apart.

Dry rolled surface

Making up of the surface irregularities of the metal surface

After dry rolling, spreading of screenings is in progress to fill voids in the coarse aggregates.

Brooming with hand brooms, to fill voids in the coarse aggregates

Sprinkling of water is in progress

Rolling after sprinkling of water

Application of binding material successively in two or more thin layers. Due to application of stone dust as screenings and binder internal friction between coarse aggregates is not getting reduced.

GR III WBM with stone screenings as per clause 405 of MORD

WBM using grade III HBG metal and crusher dust as type B screenings and binder

Surface of WBM with grade II HBG metal. Type A screenings used are 6mm and 10mm and binder is stone dust. Grade III collections in progres. Narakoduru Anantavarappadu road in Guntur District.

Surface of WBM with grade III HBG metal. Type B screenings and binder used is stone dust. Narakoduru Anantavarappadu road in Guntur District.

Table 400-11. Grading Requirements of Aggregates for the Wet Mix Macadam IS Sieve Designation

Per cent by weight passing the IS Sieve

53.00 mm

100

45.00 mm

95-100

22.4 mm

60-80

11.20 mm

40-60

4.75 mm

25-40

2.36 mm

15-30

600.00 micron

8-22

75.00 micron

0-8

WET MIX MACADAM

Materials : 40mm, 20mm , 12mm, 6mm &Stone Dust Mixing at Pug Mill with Water, Conveyed to Site, Spreading by Paver and Rolling. Relative Compaction = 98 %

DO’s 1. Ensure compliance of all material and plant requirements. 2. Check aggregate for soundness test when water absorption is more than 2 %. 3. Build shoulders simultaneously along with WMM layers. 4. Remove BT surface before WMM is laid on an existing road.

Don’ts 1. Do not use material other than crushed stone.

2. Do not allow segregation or pockets of coarse/fine material on the layer. 3. Do not allow any traffic on the WMM surface without covering it with a wearing course.

Pug mill for Wet Mix Macadam

Loading WMM into tipper at Pug mill

Laying of Wet Mix Macadam with paver

Moisture content versus Dry density relationship for Wet Mix Macadam 2.35

Moisture Content %

Dry Density g/cc

4.76

2.11

5.63

2.14

6.08

2.19

6.82

2.32

10.25

2.159

11.86

2.10

2.3

2.25

2.2

Series1

2.15

2.1

2.05

OMC = 6.82% MDD = 2.32 g/cc

0

5

10

15

Wet Mix Macadam on Mangalagiri Rayapudi road

BLACK TOPPED SURFACINGS Strengthening layers Bituminous Macadam Modified Penetration Macadam Wearing Courses Surface Dressing Open Graded Premix Carpet with seal coat Closely graded premix carpet or Mix Seal surfacing (hot mix process)

Requirements of BT Surfacing IRC:37, MORD Section 500 o High stability – resisting permanent deformation o Good durability and long life-resisting traffic abrasion o Good elastic properties o Good resistance to fatigue o Low permeability to water and air o Good workability when hot o Good skid resistance o Good riding quality o Acceptable level of noise under traffic o Economical in initial cost and maintenance

MORD 502.Prime Coat over granular base Application of single coat of low viscosity liquid bituminous material to an absorbent granular surface to any superimposed bituminous treatment MORD Table 500-1, Primer requirements Porosity Low

Surface WBM/WMM

Quantity kg/10sqm 7 - 10

Medium

Stabilised base

9 - 12

High

Gravel base

12 - 15

1) It coats and bonds loose mineral particles of granular surface 2) It water proofs the surface of the base by plugging capillary or un connected voids 3) It provides adhesion or bond between the granular base and bituminous layers

Methodology for Prime Coat 1. Bituminous primer should be slow setting bitumen emulsion, use of cutback being restricted to areas having sub zero temperature or for emergency operations. 2. The prime coat should be applied only on the top most granular base layer, over which bituminous treatment is to be applied. The granular base surface should be swept clean of dust and loose particles and where required, lightly and uniformly sprinkled with water to moist the surface. 3. The primer should be sprayed uniformly over the dry surface of absorbent granular base, using suitable bitumen pressure distributor or sprayer capable of spraying primer at specified rates and temperature so as to provide a uniformly unbroken spread of primer. Normal temperature range of spraying emulsion should be 20°C to 60°C. The rate of application depends upon the porosity characteristics of the surface to be primed and is given in above table.

DO’s 1. Use slow setting emulsion and restrict the use of cutback to subzero temperature conditions or emergency operations. 2. Use only pressure sprayers. 3. Preferably lay a trial section. 4. The Contractor to demonstrate at a spraying trial to ensure that the equipment is capable of producing a uniform spray.

Don’ts 1. Do not apply primer when the atmospheric temperature in shade is less than 10°C or when the weather is foggy, rainy or windy. 2. Do not allow pouring of primer using perforated cans. 3. Do not allow traffic on primed surface. 4. Do not apply bituminous material to a wet surface.

Check for rate of spread 20cm × 20cm × 3cm trays for binder collection

Prime coat over WMM

On WMM/WBM surface, prime coat followed by sand flushing is a better option to allow traffic for short duration

MORD 503.Tack Coat MORD Table 500-2, Rate of application of tack coat Type of surface

Bitumen emulsion Kg/sqm

Nominal bituminous surfaces

0.20 to 0.25

Dry and hungry bituminous surfaces

0.25 to 0.30

Granular surfaces treated with primer

0.25 to 0.30

Cement concrete pavement

0.30 to 0.35

Methodology for Tack Coat 1. Use a rapid setting bitumen emulsion for applying a tack coat, the use of cutback being restricted to areas having sub-zero temperature or for emergency applications. 2. The surface on which tack coat is to be applied should be clean, free from dust, dirt and any extraneous materials and dry. 3. The surface should be prepared as per sub-section 501. 4. The binder should be sprayed uniformly over the surface using suitable bitumen pressure sprayer capable of spraying bitumen and emulsion at specified rates and temperature so as to provide a uniformly unbroken spread of bitumen emulsion. For smaller jobs, a pressure hand sprayer may be used. Normal range of spraying temperature should be 20°C-60°C in case of emulsion and 50°C-80°C in case of cutback. The rate of application depends upon the type of surface and is given in above Table . 5. The surface should be allowed to cure until all the volatiles have evaporated.

DO’s 1. Plan the work so that no more than the necessary tack coat for the day’s operation is placed on surface.

Don’ts 1. Do not apply tack coat when atmospheric temperature is less than 10°C or when weather is foggy, rainy or windy.

2. Handle bituminous 2. Do not apply tack coat cutback carefully to avoid fire on a wet surface. mishap. 3. Do not allow any equipment or vehicles on Tack Coat.

MORD table 500-5,Manufacturing and Rolling Temperatures Minimum Rolling temp. ºC

Laying-ºC

Bitumen Penetration

Bitumen Mixing -ºC

Aggregate Mixing-ºC

Mixed Material ºC

35 (30-40)

160 to 170

160-175

170 Max

110 Min

140 Min

65 (60-70)

150 to 165

150-170

165 Max

100 Min

130 Min

90 (80-100)

140 to 160

140-165

155 Max

100 Min

130 Min

MORD 506 Modified Penetration Macadam (MPM) Rate of application for 10sqm area 75mm Description

Bituminous surface, cum

40mm size hand broken metal 12mm size chips

50mm

On WBM surface, cum

Bituminous surface, cum

On WBM surface, cum

0.9

0.6

0.18

0.18

AIV < 40% and FIV < 25% for coarse aggregates. Bitumen rate of application for 10sqm area (kg)

75mm

Description

Bitumen for grouting

50mm

Bituminous surface

On WBM surface

Bituminous surface

On WBM surface

20

20

17.5

17.5

Tack coat shall be as per clause 503 (table 500 -2)

1. Spread coarse aggregate of 40 mm size metal uniformly at the rate of 0.9 cum for 75 mm thickness (0.6 cum for 50 mm thickness) per 10 sqm area to proper camber/ super-elevation. Remedy all high spots and depressions by removing or adding aggregates. 2. Commence rolling with 80-100 kN rollers (three-wheel or tandem type), beginning from the edge and progressing towards the centre longitudinally. On super elevated portions, rolling should progress from lower to upper edge parallel to centre line of pavement. 3. Correct any irregularities noticed after the roller has passed over the whole area once by loosening the surface and removing or adding the coarse aggregates followed by rolling. Continue rolling till the entire surface has been rolled to desired compaction such that there is no crushing of aggregates and all roller marks have been eliminated. Each pass of roller should overlap not less than one-third of the track made in the preceding pass. 4. Heat bitumen (paving grade S-35 to S-90) to a temperature of 160°C to 180°C and spray uniformly on aggregate layer at the rate of 20 kg per 10 m2 for 75 mm thick layer and 17.5 kg per 10 m2 for 50 mm thick layer. 5. Immediately after application of bitumen, spread 12 mm size key aggregates at a uniform rate of 0.18 cum for 75 mm thickness (0.12 cum for 50 mm thickness) per 10 m2 so as to cover the surface completely and roll. Rolling should continue until the key aggregates are firmly embedded in position and stop moving under roller

DO’s 1. Ensure that aggregates conform to grading specified and are dry and clean at the time of laying. 2. Maintain the temperature of bitumen appropriate to the grade of bitumen. 3. Remove excessive deposits of binder during spray operation.

Don’ts 1. Do not undertake the work in foggy. rainy or windy weather or when the atmospheric temperature in the shade is less than l0°C. 2. Do not allow any traffic over Built up spray grout without laying wearing course or seal coat.

Modified Penetration Macadam (MPM). 40mm HBG metal at 0.6cum/10 sqm is spread, sectioned and rolled

Modified Penetration Macadam (MPM). 17.5 kg bitumen grouted and 0.18 cum/10sqm of 12mm key chips applied. Brooming is in progress.

Finished Modified Penetration Macadam (MPM) 50mm thick compacted layer.

504 BITUMINOUS MACADAM MORD Table 500-4, COMPOSITION IS Sieve (mm)

Cumulative % by weight ol aggregate passing

26.5

100

19

90 – 100

13.2

56 – 88

4.75

16 – 36

2.36

4 – 19

0.30

2 -10

0.075

0 -8

Bitumen content, % by weight of mixture

3.30 – 3.50

Bitumen Grade

35 to 90

AIV < 30%, FIV < 25% and WA < 2 %

Methodology for Bituminous Macadam 1. Prepare the base on which bituminous macadam course is to be laid and shape to the specified lines, grade and cross-section. 2. Apply tack coat over the base preparatory to laying of the bituminous macadam. 3. Bituminous Macadam should be prepared in a Hot Mix Plant of adequate capacity. Ensure manufacturing and rolling temperatures for Bituminous Macadam as specified. 4. Transfer the mixed material quickly to site of work and lay by means of an approved self-propelled mechanical paver. 5. Commence initial rolling with 80-100 kN rollers (three-wheel or tandem type), beginning from the edge and progressing towards the centre longitudinally. On super elevated portions, rolling should progress from lower to upper edge parallel to centre line of pavement. Thereafter, do intermediate rolling with vibratory or pneumatic tyred road rollers. This should be followed by final rolling while the material is still workable.

Methodology for Bituminous Macadam continued 6. Any high spots or depressions noticed after the roller has passed over the whole area once should be corrected by removing or adding premixed material. Rolling should recommence thereafter. Each pass should have an overlap of at least one-third of the track made in the preceding pass. Rolling should be continued till all rolIer marks have been eliminated. 7. For single lane roads no longitudinal joint is required, while for double-lane roads longitudinal joints may be required depending on the paver width. 8. For making longitudinal or transverse joint, cut the edges of the bituminous layer laid earlier to their full depth so as to expose fresh surface and apply a thin coat of binder. Lay adjacent new layer and compact flush with the existing layer. 9. Cover the bituminous macadam with the wearing course within a period of 48 hours. If there is any delay in providing wearing course the bituminous macadam surface should be covered with a seal coat before opening to traffic.

DO’s 1. Ensure that stone aggregate

Don’ts

1. Do not undertake the work in foggy, rainy or windy weather or conforms to the physical when the atmospheric temperature requirements and grading in the shade is less than 10°C. requirements and are dry and 2. Do not allow the difference in clean. temperature of binder and 2. In case the aggregate has poor aggregate to increase beyond 14OC affinity to bitumen use anti stripping at any time. agent with the approval of Engineer. 3. Do not allow the premix material 3. While transporting the mixture it to adhere to the roller wheels. (Do should be suitably covered by not use excess water for the purpose. Light sprinkling should do.) tarpaulin. 4. Do not use lubricating oil on the 4. Rolling operations should be wheels of the roller to prevent mix completed before the mix becomes from adhering. unworkable 5. Do not allow traffic until the mix 5. Maintain strict control on has been covered with a wearing temperature while mixing and rolling. course. 6. Regulate the rate of delivery of 6. Do not move roller at a speed material to paver to enable it to more than 5 km/h. operate continuously.

MORD 507 Surface Dressing Table 500 – 10: Size requirements of stone chips for surface dressing Type of construction

Size of chips

specification

Single coat surface dressing or first coat

13.2mm

100% passing 22.4mm sieve and retained on 11.2mm sieve

Second coat of 2 coat

9.5mm

100% passing 11.2mm sieve and retained on 5.6mm sieve

Table 500 – 10, Binder rates and chipping quantities Chipping size

Bitumen kg/m2

Emulsion kg/m2 Chips cum/m2

13.2

1.0

1.5

0.010

9.5

0.9

1.4

0.008

6.3

0.75

1.1

0.004

Appropriate technology and machinery for Surface Dressing 1. Applying Prime Coat : Hand-held lance with sprayer operated by Compressor 2.Heating Bitumen : Bitumen Boiler of small capacity

3.Applying Binder : Hand-held lance with sprayer, operated by Compressor 4. Spreading stone chips : Agricultural tractor-towed Spreader Box 5. Rolling : 80-100 kN smooth-wheeled roller

Surface dressing using 0.04 cum of 6.3 mm chips over a coat of 7.5 Kgs of bituminous material on a WBM surface laid without any gravelly soil. It not only prevents the WBM surface from raveling for a few days but also facilitate efficient laying of BT surfacing at the appropriate time

MORD 508 Open Graded Pre Mix Carpet (OGPC) 20 mm thick pre mix carpet Aggregate 13.2mmchips = 0.18cum 11.2mm chips = 0.09cum (13.2mm = passing 22.4 & retained on 11.2mm sieves 11.2mm chips passing 13.2mm retained on 5.6mm sieves) Binder Bitumen @ 14.6 kg/ 10sqm Emulsion @ 21.5 kg/ 10sqm AIV < 40%, FIV < 25% and WA < 1% for coarse aggregates.

Appropriate technology and machinery for Premix Carpet 1.Applying Prime Coat : Hand-held lance provided with sprayer, operated by compressor 2.Applying Tack Coat : Hand-held lance provided with sprayer, operated by compressor 3.Mixing of aggregates and bitumen in : Mini Hot Mix Plant, capacity of with specified quantities around 6 tonnes/hour 4.Transporting from the mixer to site : Tarpaulincovered tractor-trailer or hand barrows

Methodology for OGPC

1. Mixing should be thorough to ensure that a homogenous mixture is obtained. The temperature of bitumen at the time of mixing should be in the range of 150° C to 163° C and that of aggregates 155°C to 163°C, provided that the difference between the temperature of aggregate and the binder should not exceed 14°C. If modified bitumen is used, temperature should be as recommended in Subsection 512. The temperature at the time of discharge of the mixture should be between l30°C and 160°C. 2. The premixed material shall be spread on the road surface with rakes. 3. Commence rolling with 80-100 kN rollers (three-wheel or tandem type), beginning from the edge and progressing towards the centre longitudinally. (On super elevated portions, rolling should progress from lower to upper edge parallel to centre line of pavement). Continue rolling operations till a smooth uniform surface is achieved and all roller marks are eliminated. Each pass should have an overlap of at least one-third of the track made in the preceding pass. 4. Correct any high spots or depressions noticed after the roller has passed over the whole area once by removing or adding premixed material and recompacting. 5. Provide a seal coat to the surface immediately after laying the carpet as per details in Sub-section

DO’s 1. Ensure that the aggregates and binder satisfy the specified requirements.

Don’ts 1. Do not allow manual mixing.

2. Do not undertake work in 2. Before opening the bitumen foggy, rainy or windy emulsion drum, roll the drum weather or when the at slow speed, to and fro at minimum air temperature is least five times for a distance less than 10°C. of about 10 m to ensure proper distribution of storage 3. Do not allow any traffic sedimentation. unless the emulsion is properly set and the surface 3. As far as possible use has acquired adequate suitable cold mixing plant stability

MORD 510 Seal Coat Table 500-16, Requirement of materials fo seal coat Type of seal coat Type A Liquid seal coat

Per 10sqm Bitumen kg Emulsion kg 9.8 12 to 14

Type B Pre mix seal coat

6.8

10 to 12

Type C Pre mix seal coat using 6.7mm chips

4.5% by weight of total mixture

9 to 11

Quantity of chips per 10sqm 6.7mm chips (passing 100% on 11.2mm sieve and fully retained on2.36mm sieve) for type A Sand or grit (for type B) passing 2.36mm sieve and retained on 180 micron sieve 6.7mm (passing 100% on 9.5mm sieve and fully retained on2.36mm sieve) for type C

0.09cum 0.06cum 0.09cum

MORD 509 Mix Seal Surfacing Table 500-15, Aggregate Gradation IS Sieve designation mm

13.2 11.2 5.6 2.8 0.09

Cumulative % by weight of total aggregate passing Type A Type B

100 52 – 88 14 – 38 0-5

100 88 – 100 31 – 52 5 – 25 0-5

Chips @ 0.27cum per 10sqm Binder @ 22kg for type A and 19kg for type B

Mix Seal Surfacing 20mm thick over WMM treated with single coat surface dressing with 0.04 cum of 6.3mm chips over 7.5kg/10sq.m bituminous coat (SSD).

Mix Seal Surfacing 20mm thick over WMM treated with SSD. SSD is preferred to prime coat as we have to allow traffic.

Revendrapadu Sitanagaram runs along Buckingham canal for 4km and it was in a very bad shape with lot of pot holes and sunken portions. Number of renewals were done but the road condition remained the same.

There is lot of WBM crust with gravel blindage. The road was fully picked up, gravel and BT pieces removed to possible extent, sectioned, rolled, stone dust blindage done and rolled.

Condition of Nidubrolu Chandolu road. Soaked and softened gravel in gravel base and blindage in WBM is the cause for this condition.

Condition of Nidubrolu Chandolu road after full picking, removing gravel to possible extent, sectioning metal, rolling and dust blindage.

Condition of Nidubrolu Chandolu road after doing single coat surface dressing

Chandolu bridge to Nijampatnam road runs on high bank of irrigation canal. Doing BT patch work for BT renewal is very difficult. It is proposed to recycle the WBM crust.

Condition of Chandolu bridge to Nijampatnam road after full picking, removing gravel to possible extent, sectioning metal, rolling and dust blindage.

Chandolu bridge to Nijampatnam road after single coat surfacing over recycled surface.

Chandolu bridge to Nijampatnam road after doing BM + SDBC. Shoulder work to be done.

Repalle Tummala Gangadapalem road after picking, sectioning, stone dust blindage, rolling and single coat surface dressing

Repalle Tummala Gangadapalem road after completion BM and SDBC

Gravel collected for berms sticking to the BT wearing coat and part of the fines of gravel permeate into it. While cleaning the gravel BT layer is getting peeled off.

Berms done with selected earth on Rajupalem Bodhanam road

WBM over gravel base

Widening the formation to the required width

Both sides shouders are cut to a depth to get the required formation width at top. Selected earth with a minimum density of 1.75g/cc in layers and compacted at OMC.

Formation of top is completed and repairs to carriageway will be taken up.

After the resurfacing is completed.

MoRD Specifications and Manual - Rural Road Construction PDF

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