Method Statement For Surface Friction Treatment Selection Trial (Base Case)

CONTENTS

1. Purpose

• Scope of Work

• Definitions

• References

• Materials

• Tools, Plant  & Equipment

• Safety

• Prior Activities

• Procedure

1. Responsibilities

1. Attachments

1. Purpose

1.1       To ensure that the Surface Friction Treatment (SFT) Selection Trial (Base Case) is executed safely and in accordance with the contract requirements and that all quality assurance/ control activities are conducted in a systematic manner, works are inspected and conformance is verified and documented.

• Scope of Work

• This procedure is applicable to the following works associated with the Project titled, “New 2K Runway – Main Runway Works” – Contract Number NRTW-1008-CN.

• This method statement outlines the procedures to be followed in the conduction of the Surface Friction Treatment Selection Trial (Base Case).

• The selection trial shall be carried out on the airport service road MCLP.  The location and extent of the trial area are shown in the attached Drawing Nos. 1 thru 4.

• Definitions

• CM                  Construction Manager
  • SE                   Site Engineer
  • ME                   Material Engineer
  • ITP                  Inspection and Testing Plan
  • AHA                 Activity Hazard Analysis
  • JHA                 Job Hazard Analysis
  • SFT                 Surface Friction Treatment
  • PPE                 Personal Protective Equipment
  • PMB                Polymer Modified Bitumen
  • ICAO               International Civil Aviation Organization

• References

• Specifications: Volume 3 – Section 9 – Part A – General, Civil and Mechanical Infrastructure

• Drawings:        Volume 2 – Section 8 – Part B – Civil, Mechanical and Navaids.

• BOQ:   Bill No. 3
• Materials       

• Water
  • Bituminous Base Course Material (complying to Clause 331 of contract specifications)
  • PMB Wearing Course (complying to Clause 331 of contract specifications)
  • Tack Coat of Grade MC-30 Cut-Back Bitumen or SS1H Emulsion
  • Sand Patch Test Kits
  • Warning Tapes
  • Temporary Signs
  • Safety Barrier
  • Traffic Cones
  • Traffic Lights

• Tools, Plant & Equipments:

• Mixing Plant for Bituminous Base Course
  • Mixing Plant for PMB Wearing Course
  • Tipper Trucks
  • Pavers
  • Steel Roller
  • Pneumatic Tire Roller
  • Bitumen Sprayer Tanker
  • Air Compressor
  • Findlay Irvine MK2 Grip Tester
  • Personal Protective Equipment

• Safety

• Prior to the commencement of any activities, the workforce will receive an induction talk on the project site safety requirements. This induction talk will include both activity safety issues, as well as general safety requirements.

• Front line supervisor will ensure that Personal Protective Equipment is worn by site personnel at all times during construction activities.

• Heat Stress Training will be provided.

• Adequate cool drinking water, shade, and salt water tablets will be in place.

• Plant and Equipment will be provided with back-up alarms, lights, and all other applicable safety devices.
• Prior Activities

• Surface Preparation

• The existing road surface will be cleaned with an air compressor, ensuring that the surface is dry, clean, and free of dirt and/or loose material.

• An approved tack coat of grade MC 30 cut-back bitumen or SS1H emulsion shall be applied to the existing cleaned road surface at the rate of 0.25 to 0.35 litres per m², in accordance with Clause 331.33 of the contract specifications, before placing the regulatory base course material.

• Application of the tack coat will be done by a tanker fitted with nozzles at the back of the tank to allow even spreading of bitumen.

• Sufficient time will be allowed for the curing of the tack coat before laying the regulatory layer of bituminous base course.

• Placing of Regulatory Bituminous Base Course Material

• A layer of regulatory bituminous base course material, of varying thickness, will need to be placed to achieve the necessary longitudinal and transverse slopes of the testing surface.  The thickness of this regulatory bituminous base course material will vary from a minimum of 0mm to a maximum of 60mm.

• Placing of the regulatory base course will be carried out in accordance with the approved method statement 1008-OAJ-MS-1024, Revision 0 Method Statement for Placing of Bituminous Pavement.  Testing of the regulatory bituminous base course layer will not be required.

• Placing of 50 mm PMB Wearing Course

• Placing and compaction of the 50 mm PMB wearing course, to the limits and extents shown in the attached Drawing Nos. 2 thru 4, will be carried out in accordance with the approved method statement 1008-OAJ-MS-1024, Revision 0 Method Statement for Placing of Bituminous Pavement.

• Testing of the PMB wearing course layer shall be in accordance with Items 6.2 and 6.3 of the approved ITP No. 1008-OAJ-ITP-1024, Rev. 0 Inspection and Test Plan for Supply and Placing of Bituminous Paving Materials.
  • It shall be ensured that the smoothness of the finished surface of the PMB wearing course shall be in compliance with both Clause 331.37 of the contract specifications and Section 5.1, Attachment A, Annex 14 of ICAO,  which require that finished surface of the wearing course is to be of such regularity that, when tested with a 3 metre straightedge placed anywhere in any direction on the surface, there is no deviation greater than 3 mm between the bottom of straightedge and the surface of the pavement  anywhere along the straight edge.

• It shall be ensured that the transverse slope of the pavement surface is 1.5%, in compliance with the requirement of Section 3.1.18, Annex 14 of ICAO for Code Letter F airports, and to match the transverse slope of the New 2k Runway pavement.

• Measurement of Surface Texture Depth – Sand Patch Test

• Measurements of surface texture depth shall be undertaken using the sand patch test, in accordance with Clause 331.38 of the contract specifications and Section 2.3, Airport Services Manual, Part 2 – Pavement Surface Conditions.

• A normal Sand Patch Test apparatus consists of the following:

1. A metal cylinder of 86 mm internal depth and 19mm internal diameter.
2. A flat wooden disc, 64 mm in diameter, with a hard rubber disc, 1.5 mm thick, stuck to one face, the reverse face being provided with a handle.
3. Dry natural sand, with a round particle shape, which will pass through a 300-micron sieve and be retained on a 150-micron sieve.

• Test Procedure:

1. Dry the surface to be measured and sweep clean with a soft brush.  Fill the cylinder with sand, tapping the base three times on the surface to ensure compaction, and strike off the sand level with the top of the cylinder.

• Pour the sand into a heap on the surface to be tested.  Spread the sand over the surface, working the disc with its face kept flat, in a circular motion so that the sand is spread into a circular patch with the surface depressions filled with sand to the level of the peaks.

• Measure the diameter of the patch to the nearest 5 mm.
• The texture depth is 31,000/D², where D is the diameter of the patch in mm.

• The frequency of the testing shall be one surface texture test per 100 m².

• Per Sections 1.2, and 2.3.2 of the Airport Services Manual, Part 2, and Section 3.1.24 of Annex 14, ICAO it is recommended that the average surface texture depth of a new surface not be less than 1.0 mm.  However, Section 3.23 of FAA Advisory Circular 150/5320-12C recommends that the average surface texture depth of a new surface not be less than 1.14 mm.

• Preparation for Surface Friction Test

• The test pavement shall be inspected prior to conducting the surface friction tests to ensure that the surface is dry, clean and free of dirt and/or loose material.

• The Grip Tester test hardware, tire(s), and data acquisition system shall be checked for proper configuration and working condition.

• The Grip Tester instrument calibration shall be performed to manufacturer’s specifications and store (record) values.

• A suitable check of the water distribution system shall be performed so that the desired and consistent water quantity is provided in front of the test tire(s) at each planned test speed.  It shall be ensured that a water flow rate that will achieve average water depth on the surface of 1 mm is achieved.

• Test runs shall be performed on a given test surface to stabilize the wet friction measurements and to achieve an acceptable repeatability of +0.03 during subsequent runs.  If this level of consistency is not achieved in two series of test runs at similar speed, the measuring and data acquisition systems will be inspected for any irregularities, corrected as necessary, and recalibrated before continuing the certification tests.

• It shall be ensured that the personnel operating the equipment are fully trained and current in all procedures.

• The Grip Tester towing vehicle shall be checked for adequate braking capability.

• Procedure

• Surface Friction Tests

• Surface friction tests for the base case (non-grooved PMB bituminous surfacing), using Findlay Irvine MK2 Grip Tester, shall be conducted in accordance with FAA AC 150/5320-12C, and Annex 14, Volume 1, Attachment A, ICAO and Airport Services Manual, Part 2.

• The surface friction tests of the trial area shall be conducted by personnel from the Department of Civil Aviation (DCA), Government of Dubai.  DCA’s Findlay Irvine GT178 Type MK2 Grip Tester, hereinafter referred to as the Grip Tester, shall be employed to conduct the friction test.

• Details of Findlay Irvine MK2 Grip Tester:

1. The Findlay Irvine MK2 Grip Tester is a Continuous Friction Measuring Equipment (CFME) capable of using self-wetting features to enable measurements of the friction characteristics of the surface to be made at a water depth of at least 1 mm.

• The Grip Tester is a lightweight, three-wheel trailer which measures friction using the braked wheel, fixed slip principle.

• It has a single measuring wheel fitted with a smooth tread tire made to ASTM E1844 specification.  The Grip Tester tire uses 140 kPa inflation pressure.  The wheel is mounted on an instrumented axle which measures both drag force and vertical load.  From these measurements, the dynamic friction reading is calculated and transmitted to a data collection computer normally carried in the cab of the towing vehicle.

• The computer calculates and stores the test speed for each 10 metres of friction reading.  The Grip Tester uses a friction scale, which ranges from 0.00 to 1.00, and provide friction averages for each 150 metre of the pavement length tested. When the test is completed, average friction reading for each of the test run is displayed on the computer.  The results may be printed or stored in a database.

• Details of the Findlay Irvine MK2 Grip Tester are attached.

• The surface friction tests shall be conducted at two speeds: 65 kmph and 95 kmph.  The lower speed determines the overall macrotexture / contaminant /drainage condition of the pavement surface.  The higher speed provides an indication of the condition of the surface’s microtexture.

• A maximum of four test surveys and a minimum of two test surveys, each of 200 metres length, can be conducted on the 400 m x 5.00 m test area being provided.  Surface friction tests will be conducted in one direction only (east to west).

• An acceleration length in excess of 400m is provided to enable the towing vehicle to attain the required speeds.  An deceleration length of 180m, beyond the test area, is provided to allow the vehicle to come to a complete stop.

1. Responsibilities

1. The CM will coordinate with SE and ensure that all necessary resources to implement the approved method statement, JHA, and AHA have been allocated to the task.

1. The SE will ensure that the site preparation activities are conducted according to the approved method statement, JHA and AHA.  The SE will also ensure that all in-situ tests, as required by the ITP, are implemented.

1. The ME will ensure that the materials being used are in accordance with the project specifications and the approved material submittals.

1. It is the site supervisor’s responsibility to organize the work in a safe manner to ensure that safety and protective equipment are being properly utilized.  He must also ensure that the AHA and JHA are implemented and the approved method statement procedure is followed and the ITP is applied.  Please note that the AHA and JHA have been previously submitted and approved along with the relevant method statement for laying of bituminous pavement.