METHOD STATEMENT FOR CONCRETE BLINDING AT SUB-STRUCTURES

1.0 SCOPE

This method statement describes the work procedures, quality assurance, and quality control for the concrete blinding at sub-structures.

2.0 RESPONSIBILITY

The Project Manager is overall responsible for all aspects of the works/project.

The Project Site Engineers are responsible for the proper execution, arrangement, coordination, and supervision of the quality, safety, and delivery of work.

The QA/QC Manager/Engineer shall ensure that the execution team follows this method statement and implements the site inspection procedures.

The MEP Coordinator/Engineers are responsible for coordinating the Mechanical and Electrical works related to underground works.

The Safety Engineer will ensure the implementation of safety on the worksite.

The Approved Ready Mix Concrete Supplier is responsible for the continuous delivery of concrete as per the approved design mix and project specifications, from batching and transporting to controlling the temperature and slump tests, as well as taking the required concrete test cube samples upon arrival on-site.

3.0 MATERIALS & EQUIPMENT

Blinding Concrete: Ready-Mixed, as per the approved design mix by Engineers/Consultants.

Mobile Concrete Pump

Mobile Tower Crane (If required)

Bonding Agent (if required)

Approved Gauge Polyethylene Sheets

Clean/ Potable Water

Power-Driven Floats

Wooden/ Aluminum Screeder Bar

Dumpy Level with Stadia Rod

Air Compressor

4.0 WORK PROCEDURES

Preparation Works

Excavation works up to the formation level of the sub-structures should be completed and checked for required elevations by Engineers and the approved Independent Testing Agency to ensure bearing stability.

For normal excavation of undisturbed earth, the cut earth surface at the formation level should follow the standard method statement for soil backfilling.

Establish the reference 1.0m elevation from SSL and the high-level elevation of the concrete surface for blinding, with a minimum requirement of 75mm. Shuttering should be provided around the perimeter ends of the proposed casting area.

Approved soil treatment/anti-termite must be applied prior to laying polyethylene sheets on the soil surface.

Install the approved polyethylene sheet on top of the soil surface, as per the installation procedure by the manufacturer or supplier.

Concreting Works

Blinding concrete shall be poured on the prepared area using a concrete pump for large volumes, or direct pouring with a chute, following the basic method statement for placing concrete using a mobile pump or direct pouring.

In case of delays in the concrete, the incomplete poured strip should be treated with bonding agent and/or cement slurry before placing fresh concrete.

When the ready-mix concrete is placed or poured on the area, level the concrete according to the approved blinding level.

The surface finish of the blinding shall be smooth, using power-driven floats to achieve the required surface finish for receiving waterproofing membranes.

Curing & Protection

During concreting and throughout the initial hardening, the blinding shall be immediately cured with an approved curing compound or water curing.

The work area shall be closed off from traffic during preparation, concreting, and curing.

Slump Test & Temperature Control

Slump tests and temperature checks of the concrete will be carried out for every truck mixer that arrives on-site. Results will be recorded in the delivery ticket and the concrete monitoring log prior to placement at the site. The slump test and temperature will follow the approved design by Engineers.

Concrete Test Cubes Sampling

The frequency of sampling concrete cubes shall be as per the instructions of the Engineers/Consultants or according to standard specifications. Concrete sampling shall be carried out in accordance with Clause of BS 1881 Part 102.

5.0 FIELD QUALITY CONTROL & INSPECTIONS

The necessary site inspections, as stated in the work procedures, shall be carried out in accordance with the site inspection procedures.

Site Engineers and Project Engineers will monitor the execution of work to ensure compliance with this method statement.

Upon completion, a joint quality inspection between the Contractor, QC Engineer/Project Engineer, and the Consultant’s Engineer shall be carried out to verify the quality of the finished surface of the blinding. Any unsatisfactory workmanship or defects found shall be rectified, and preventive actions shall be taken to avoid recurrence in subsequent works.

6.0 SAFETY PRECAUTIONS

Prime importance shall be given to the safety of personnel and protection of utility services. Ensure that personnel involved are thoroughly aware of the company’s safety regulations.

Any machinery and equipment must only be operated by well-trained and experienced personnel.

Protective clothing and equipment will be necessary. Ensure that any special clothing or equipment required (including signs relating to the wearing of rubber boots, helmets, eye protection, ear defenders, visibility vests, etc.) is ordered and available for use on-site. Ensure that subcontractors are made aware of any site requirements, especially regarding the wearing of safety helmets. Instruct staff in the correct handling and lifting of materials, especially those that could cause injury to the hands.

A risk assessment letter should be issued by the Safety In-charge before the start of the activity, and it should be posted immediately at the working area during the activity.

7.0 REFERENCE DOCUMENTS

Project contract specifications

Project contract and Approved Shop Drawings