Material Testing and Field Material Testing and Field Compliance TestCompliance Test

Universal Rural Roads Access ProgramTraining of Trainers for Contractors

02 – 07 August 2013, Chancho

Ethiopian Roads Ethiopian Roads AuthorityAuthority

Presentation OutlinePresentation Outline

Background

Need for Testing and Specification

Material Laboratory Testing

Field Compliance Test

Test data management & QC

BackgroundBackground

Road formation

◦Site clearance◦Earth work/ embankment

construction◦Subgrade construction◦Subbase and ◦Surfacing

Engineered natural surfaces

Typical gravel road cross section

Embankment/SubgradeEmbankment/SubgradeMaterial quality Requirements for

borrow material, Earth work for embankment and subgrade construction

The material used in embankment, sub-grade, shoulders, etc. shall be soil, gravel, a mixture of these or other material approved by an Engineer. It shall be free from logs, stumps, roots, rubbish, etc.

Cut and Fill (Embankment) Cut and Fill (Embankment) SectionsSections

Granular SubbaseGranular SubbaseGravel material to be used for sub-

base shall be obtained from approved sources in borrow areas, cuts or existing pavement layers.

The complete sub-base shall contain no material having a maximum dimension exceeding two-thirds of the completed layer thickness.

Gravel Sub-base material shall, unless otherwise stated, conform to specification requirements in terms of:

Need for Testing and SpecificationNeed for Testing and Specification

Material testing is essential to verify material characteristics for application trials, detect defects, analyze failures, improve new materials or conduct basic research.

The materials used in construction projects must meet

strict quality regulations, standards, and service life requirements.

The materials will affect the quality, costs, sustainability and environmental impact of the construction project. 

……. cont. cont• The technical staff involved in testing areas

should have educational certificate and work experience.

• The Engineer shall verify that the laboratory has the appropriate equipment, calibration and verification records, test procedures, and trained personnel to perform every procedure in the proposed scope.

• Test procedures shall be performed with applicable materials

Contractor’s Responsibilities from Contractor’s Responsibilities from the view of the provision of the the view of the provision of the ContractContractGeneral ResponsibilitiesThe Contractor has obligation with respect to

the supply of materials and workmanship.

Do the work with care and skill in a proper and workmanlike manner;

Use materials of good and viable quality;

Ensure that both the work and the materials should reasonably fit for the purpose they are wished-for.

……contcontClause 8.1

The Contractor shall, with due care and diligence, execute and maintain the works and provide all labour, including the supervision thereof, materials. Construction plant and all other things, whether of a temporary or permanent nature, required.

Clause 36.1 All materials and workmanship shall be of the respective

kinds described in the Contract and in accordance with the Engineer’s instructions, and shall be subjected from time to time to such tests as the Engineer may direct at the place of manufacture of fabrication, or on the site or at such other places as may be specified in the contract.

……contcontClause 36.2.

All samples shall be supplied by the Contractor at his own cost if the supply thereof is clearly intended by or provided for in the contract.

Clause 36.3.

The Cost of making any test shall be borne by the Contractor if such test is clearly intended by or provided for in the contract.

Material Standards to be Met on Completion of Construction

The Specification sets out materials standards to be met by each major construction material tested in the Site laboratory.

1209 Specifications American, British and Ethiopian standards are

used in this Technical Specification. In the absence of any definite provisions in the Specification on any particular issue, reference may be made to the latest codes of AASHTO, ASTM, BS or Ethiopian standards in this order of precedence.

……contcont3202 MATERIALS FOR EMBANKMENTSa) Fill The following soils are unsuitable for construction of

embankments: • Materials with more than 5% by weight of organic

materials • Materials with a swell of more than 3% • Clays with plasticity index over 45 or a liquid limit over

90.

b) Improved Subgrade The following are minimum requirements for fill materials

to be used in area of weak sub-grade: • Minimum 25% passing 2.36 mm sieve. • Ip less than 30. • Reject index less than 10% • Soils shall be non-expansive, non-dispersive and free

from any deleterious matter.

……contcontSERIES 4000: CULVERT AND DRAINAGE WORKS Concrete cube strength aggregate water

5102 Gravel Wearing Course The minimum requirements for gravel wearing

course material Maximum size (mm) Oversize Index (Io) Shrinkage product (Sp) Grading coefficient (Gc) Soaked CBR (at 95% Mod AASHTO) Treton Impact Value (%)

Laboratory TestingLaboratory Testing

Basic testing requirements – Soils

◦Atterberg limits (LL, PL)◦Linear shrinkage◦Particle size distribution – grading ◦Moisture content and compaction◦California Bearing Ratio (CBR)

UnsuitableUnsuitable soil materials for soil materials for subgradesubgrade

Clay soil which contains the value of Liquid Limit more than 80% and/or Plasticity Index more than 55%,

It is flammable materials (oily), and organically clay soil,

Contain lots of rotten roots, grass and other vegetation,

Soil which is soft and unstable because it is too wet or dry which makes it difficult to compact properly.

Desirable Properties of Soil as Desirable Properties of Soil as Subgrade MaterialSubgrade Material

Stability.Incompressibility. Minimum changes in volume and

stability under adverse condition of weather and ground water.

Permanency of strength.Good drainage.Ease of compaction.

Granular SubbaseGranular SubbaseGrading limits

Grading Modulus

Plastic Index, PI

Compaction requirements

CBR

Gravel wearing surfaceGravel wearing surfaceBased on

◦Shrinkage product (linear shrinkage)◦Grading Coefficient

Atterberg LimitAtterberg Limit

Casagrande LL Device PL Device

Plastic index

PI = LL - PL

Phase Solid Solid statestate

Semi-Semi-solid solid statestate

Plastic Plastic statestate

Liquid Liquid statestate

SuspensioSuspensionn

Water

Limits

Shrinkage

Constant volume

Condition

Hard to soft

Workable Sticky

Slurry Water-held

suspension

Shear strength [kN/m2]

Negligible to Nil

Moisture content

Soil phases and Soil phases and Atterberg limitsAtterberg limits

Dry soil

Shrinkage limit

Plastic limit

Liquid limit

0 SL PL LL

Sticky limit

Plastic indexPlastic index

Water content increasing

Volume increasing

Shear strength decreasing

(~1.7)(~170)

PI

Particle Size DistributionParticle Size Distribution

Particle Size DistributionParticle Size DistributionGradation

◦Poor/ Uniform◦Well/ continuous◦Gap graded

If there are a lot of different fractions between the largest and the smallest, the sample is well graded. If only a few sizes can be seen, the sample is single sized or poorly graded. Single-sized materials do not compact well, because there are no suitably small-sized particles to fill the empty voids between the bigger particles a good mechanical interlock

States of soil aggregate States of soil aggregate mixturesmixtures

Alemgena Alene, PhD CENG6305 – Ch2

High stability when confined

High stability when confined

High stability when confined AND dry

No cohesion High cohesion when dry

High cohesion when dry, low when wet

High angle of internal friction

High angle of internal friction

No angle of internal friction when wet

Not affected by moisture conditions

Moderately affected by moisture conditions

Greatly affected by moisture conditions

Very difficult to compact

Moderately dificult to compact

Not difficult to compact at right moisture level

a) no fines b) enough fines c) excess fines

Purpose of soil Purpose of soil classificationclassification

Development of soil Development of soil classificationclassification

Basis of soil classification Basis of soil classification systemssystems

Key soil components in soil Key soil components in soil classification systemsclassification systems

Extension of USCS for LVRExtension of USCS for LVR

Comparison AASHTO and USCS (Lia Comparison AASHTO and USCS (Lia 1970)1970)

Comparison of soil classification Comparison of soil classification systemssystems

Material Classes for Pavement Material Classes for Pavement formationformation

ERA Testing StandardsERA Testing Standards

Differences in Test Differences in Test MethodsMethods

Differences in Test Differences in Test MethodsMethods

Differences in Test Procedure - Differences in Test Procedure - CBRCBR

Rationale for SpecificationRationale for Specification

Specs and Use of Local Specs and Use of Local MaterialsMaterials

Appropriateness of current Appropriateness of current specsspecs

Use of local materialsUse of local materials

ERA Low Volume RoadsERA Low Volume RoadsMaterial requirements for

roadbase◦A wide range of materials including

lateritic, calcareous and quartzitic gravels, river gravels and other transported and

residual gravels, or granular materials resulting from

weathering of rocks can be used successfully as road base materials

Particle size distribution for natural gravel base

Concrete TestConcrete TestConcrete grade shall be

confirmed at least through strength test

Field Compliance TestsField Compliance Tests

Field density – Sand cone replacement

Strength – Dynamic cone penetrometer

Dynamic Cone Penetrometer (DCP)Dynamic Cone Penetrometer (DCP)

• How to do test

• How to analyse data

• How to calculate Structural Number

· 60° INC

Ø 20mm

Key:-1 Handle2 Hammer (8kg)3 Hammer shaft4 Coupling5 Handguard6 Clamp ring7 Standard shaft8 1 metre rule9 60° cone

7

8

9

5

4

9

1

2

3

6

Dynamic Cone Penetrometer

100

10

50

5

15 50 100101

1. Kleyn and Van Heerden, 1983 (60° cone)2. Smith and Pratt, 1983 (30° cone)3. Van Vuuren, 1969 (30° cone)4. TRRL, 1990 (60° cone)

DCP (mm/blow)

CB

R (

per

cent

)

4

2

1

3

1. Log10 (CBR) = 2.632 - 1.28 Log10 (mm/blow)

2. Log10 (CBR) = 2.555 - 1.145 Log10 (mm/blow)

3. Log10 (CBR) = 2.503 - 1.15 Log10 (mm/blow)

4. Log10 (CBR) = 2.48 - 1.057 Log10 (mm/blow)

DCP - CBR RELATIONSHIP

DCP TEST

Site/road:Test No:Section No/Chainage:Direction:Wheel path:

Zero reading of DCP:Started test at:

Date:

No.Blows Blows mm No.

Blows Blows mm No.Blows Blows mm

DCP TestDate:_______________________

Site/Road Addis Ababa - GohatsionTest No._______________________Section No.Chainage 115+000 RHS

Zero reading of DCP: 100

Direction:________________________

Started test at: Subgrade

Wheel Path: ______________________

No.Blows

∑Blows

mmNo.

Blows∑

Blowsmm

No. Blows

∑Blows

mm

1   150            

1   180            

1   210            

1   230            

1   250            

1   265            1   280            1   295            1   315            1   330            1   340            3   345            5   350            5   355            

10   360            10   362            10   362                                                             

Alemgena Alene, PhD CENG6302 - Ch6

100

0

200

300

400

500

600

700

800

900

1000

1100

1200

40 80 120 1600D

epth

(m

m)

Number of blows

RoadbaseThickness 266 mm

CBR 41 per cent

Sub-baseThickness 380 mm

CBR 20 per cent

Gravel surfacingThickness 220 mmCBR >100 per cent

SubgradeCBR 13 per cent

Typical DCP result