5: PROOF ROLLING TEST

5.1 GENERAL ......................................................................................................................................... 1

5.2 MACHINERY AND EQUIPMENT ................................................................................................ 1
5.3 TESTING PROCEDURE ................................................................................................................. 1
5.4 EVALUATION OF TESTING ......................................................................................................... 2
5.5 REMEDIAL WORKS FOR SOFT SUBGRADE ........................................................................... 3
5.6 APPENDIX 20A : EXAMPLES TO MEASURE PROOF ROLLING TEST .............................. 4
5.7 APPENDIX 20B: SAMPLE OF PROOF ROLLING FORM ........................................................ 6
5.8 APPENDIX 20C: SAMPLE OF FILLED PROOF ROLLING FORM ........................................ 7

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 5: PROOF ROLLING TEST

5.1 General

The proof rolling test shall be done to test the uniformity and stability of the subgrade compaction
in compliance with the specification requirements in Section 2: Earthworks.

The test was carried out at the top 300 mm of the subgrade layer (i.e. at formation levels in areas
which are to receive pavement structures) in locations as shown on the Drawings or as directed by
the S.O. after the layer was compacted up to 95% of the maximum dry density and trimming of
capping as per specification tolerance.

5.2 Machinery and Equipment

5.2.1 To carry out proof rolling test, the proof roller and equipment that shall be provided by the
Contractor to the approval of the S.O. are as follows:

(a) Tandem axle, dual wheel truck with

(i) Suitable loading platform
(ii) Max. gross weight with load/ballast : 50 000 kg (50 tonnes)

(b) Heavy pneumatic tyres with

(i) Number of tyre : 2 nos. per axle
(ii) Tyre size : 508 mm
(iii) Tyre pressure : 1030 kPa (150 psi)

(c) Straight edge

(d) Hand penetrometer
(e) Tyre pressure gauge

5.2.2 The proof roller shall have a platform that is suitable for loading and supported on at least two axes
with not more than two pneumatic tyres wheel per axle. The Contractor shall ensure that all the
wheels and the load shall be properly regulated to ensure that the load carried are balanced and
stable when operating on uneven surfaces.

5.2.3 In working condition, the proof roller also shall have a minimum contact width of 2.3m between
the two tyres per axle and it shall be well designed because gross weight of loaded truck may be
various uniformity from 25 000 kg (25 tonnes) to 50 000 kg (50 tonnes) of loading.

5.2.4 Before the proof rolling test started, the actual weight of the roller and the tyre pressure to be used
in each test area shall be determined. The actual weight of the proof roller shall refer to the largest
weight of the proof roller, while the tyre pressure shall be the lowest tyre pressure that can be
considered practicable; all subject to the approval of the S.O.

5.3 Testing Procedure

5.3.1 Before commencing the proof rolling test, the Contractor shall ensure that all the requirements
specified under the Clause 17.2 has been prepared and complied to the approval of the S.O.

5.3.2 Tyre pressure of proof roller shall be ensured not less than 90% of 1030 kPa (150 psi) during
weight of loads increased to 50 000 kg (50 tonnes).

5.3.3 The proof rolling test machine shall be operated within the speed 4.0km/h to 8.0km/h or a

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 comfortable walking pace. The speed proof roller shall be adjusted to allow measurement of
settlement, cracking, elastic movement or plastic movement from the effects of tyre rut at its path.

5.3.4 Proof rolling test shall be carried out systematically in longitudinal lanes. It shall be commenced
outside one edge of the area to be proof rolled and consecutive lanes shall overlap each other to
ensure that every part of the surface to be proof rolled receives at least 5 coverage of two tyre of
the roller. Only one trip of the proof roller shall be made on any area.

5.3.5 The proof rolling test shall not be performed during conditions of the subgrade layer is too dry or
too wet and the testing also shall not be done at a distance of less than 4.6 m from the bridge
abutment and/or retaining wall.

5.4 Evaluation of Testing

5.4.1 The vertical deformation limits is termed as Failure Deformation Limit (FDL) and it shall be
measured as per figure below:

Figure 17.1: Failure Deformation Limit (FDL)

5.4.2 The subgrade layer shall be checked to ensure it has complied with the test requirements. The
results of the test shall be evaluated as follows:-

(a) The tyre ruts settlement or deflection less than 25 mm shall be acceptable.

(b) In general, if the tyre ruts settlement or deflection exceeding 25 mm but not more than 150
mm shall be considered a failure and the Contractor shall be reworked and compacted to the
required density.

(c) But if the results show the tyre ruts settlement or deflection exceeding 25 mm but not more
than 50 mm, it can still be accepted if there is not substantial cracking or lateral movement
of the soil.

(d) If the tyre ruts settlement or deflection exceeding 50 mm but not more than 150 mm, it shall
be considered a failure. The Contractor shall be reworked and compacted to the required
density.

(e) Otherwise if the tyre ruts settlement or deflection exceeding 150 mm, the Contractor shall
be done the remedial works as directed by the S.O. and in accordance with the Clause 17.5
of this Specification.

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5.4.3 Additional proof rolling test shall be carried out as specified follows:-

(a) When remedial work is performed under Item 17.4.1 (e), a final proof rolling test shall be
performed upon completion of the work.

(b) Otherwise if remedial work is performed as directed under Item 17.4.1 (b) or Item 17.4.1
(d), a second proof rolling test roll may be required if directed by the S.O.

5.5 Remedial Works for Soft Subgrade

5.5.1 Where proof rolling test indicates areas of soft subgrade or areas of non-uniform subgrade stability
(i.e. the areas results in deflection exceeding 150 mm), the S.O. shall investigate for the source of
the problem by directing the Contractor to carry out the test pit.

5.5.2 The test pit depth of 0.6m to 1.5m shall be excavated at the failure location by using the excavator
or backhoe or as directed by the S.O. Test pit shall be excavated across the width of the subgrade at
locations that have failed.

5.5.3 Further investigation of the soft subgrade shall be done in terms of the subgrade materials, moisture
content test and density.

5.5.4 The subgrade shall be corrected to a uniform and satisfactory stability as directed by the S.O. If
satisfactory subgrade stability cannot be obtained by moisture control and compaction, the
Contractor shall be removed the top 300 mm (or as directed by the S.O.) of the soft materials and
replaced with suitable materials up to the formation level as shown on the Drawings.

5.5.5 Then the replacement materials shall be compacted to the required density as per Specification.

5.5.6 The test pits shall be filled out correctly and backfill with suitable material. The backfill materials
shall be compacted layer by layer to the required density as per Specifications.

5.5.7 A final proof rolling test shall be performed upon completion of the work to check the uniformity
and stability of the subgrade compaction in compliance with the Specification requirements.

5.5.8 No payment shall be made for excavation, re-compaction or compaction of other suitable material
required as a result of this Clause if it is shown that the Contractor if it is shown that the Contractor
fails to comply with the requirements of the Specifications of Clause 2.2.3 and 2.2.4 in Section 2:
Earthworks.

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5.6 APPENDIX 20A : EXAMPLES TO MEASURE PROOF ROLLING TEST

Figure 20.2: The proof rolling test shall be carried out at 5 paths per lane

Figure 20.3: The proof rolling test measurement

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Rut Tyre Depth, R (in mm):

CASE 1: R1 = 160mm – 150mm

= 10mm …………………..Acceptable 1
1
- The proof rolling test was accepted because the deflection less than 25 mm.

CASE 2: R3 = 190mm – 150mm

= 40mm ………………….. Failed 2 / Acceptable 3
2
- The proof rolling test was failed because the deflection exceeding 25 mm but not more than 150mm. The
subgrade formation shall be reworked and compacted to the required density.
3
- The proof rolling was accepted if there is not substantial cracking or lateral movement of the soil.

CASE 3: R2 = 210mm – 150mm

= 60mm ………………….. Failed 4
4
- The proof rolling test was failed because the deflection exceeding 50 mm but not more than 150mm. The
subgrade formation shall be reworked and compacted to the required density.

CASE 4: R4 = 320mm – 150mm

= 170mm ………………….. Failed 5
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- The proof rolling test was failed because the deflection exceeding 150 mm. The subgrade formation shall
be shall be done the remedial works as directed by the S.O.

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5.7 APPENDIX 20B: SAMPLE OF PROOF ROLLING FORM
PASUKAN PROJEK ECER, CAWANGAN JALAN
PROJEK CENTRAL SPINE ROAD (CSR)
PAKEJ
SEKSYEN

CHAINAGE : DATE : MAX. GROSS WEIGHT OF PROOF ROLLER : kg ( tonnes)

REF. NO. TIME START: AM / PM* TYRE PRESSURE : kPa
WEATHER : Sunny / Cloudy / Rainy * TIME FINISH: AM / PM* HEIGHT OF STRAIGHT EDGE : mm

LANE OR LOCATION
RHS LHS Remarks
SHOULDER SLOW LANE FAST LANE FAST LANE SLOW LANE SHOULDER

Elastic or Plastic
Depth (mm) (R = Rut Tyre) Deflection (mm) (R = Rut Tyre) Cracking
LOCATION Movement Remarks
R1 R2 R3 R4 R5 R6 R1 R2 R3 R4 R5 R6 (Yes/No) (Yes/No)

* Delete

Tested By: Checked By: Witnessed By:

Name: Name: Name:

Date: Date: Date:

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5.8 APPENDIX 20C: SAMPLE OF FILLED PROOF ROLLING FORM