What is Concreting ?
Concrete is a heterogeneous mixture of cement, coarse aggregate, fine aggregate(sand) and water. In addition to the above, concrete needs the use of special materials, which is admixture to reduce the water-cement ratio of the mix. Mineral or chemical admixtures are generally used for construction as per requirement. Nowadays, concrete is the most used construction material throughout the world. Before the start of concreting in construction projects, there must be proper planning and a checklist which have to follow.
Also, Read: Concrete Ingredients – Important Properties and Tests
Also, Read: Factors Affecting Strength of Concrete – Construction Civil
Pre-Construction Activities Before Concreting:
- Obtain contract documents, including drawings and work programme.
- Visit the site to ascertain the availability of access, services and space for working areas.
- Summarize all the principal quantities for concreting in Construction Project.
- Assess sources of materials
- Assess the availability of the construction plant and output.
Required Technical information before construction:
- For each mix, obtain information regarding the following:
- Type and grade of concrete
- Type of cement to be used for concreting in construction
- Standard and maximum size of aggregateย
- Minimum and maximum cement content
- Admixtures, if anyย
- Workabilityย
- Water cement ratio
- Obtain the following information regarding concreting:ย
- ย Surface finish and formworkย
- Temporary works design to be submittedย
- ย Reinforcement
- ย Testing requirements
- ย Ancillary itemsย
- Any particular restrictions/information to be provided
Also, Read: Properties of Concrete – Introduction to Good Concrete Practice
Also, Read: Design Mix of Concrete – Detailed Procedure With Calculation
Planning Before Start of Concreting in Construction Project:
- Prepare a site management plan for Concreting in Construction Project
- Design temporary works
- Design formwork reuse system
- Prepare test programme for approval of materials
- Calculate labour requirements and output targets
- Sketch provisional site layout
- Assess daily concrete demand
- Assess the rate of pour for individual components
Project Decisions:
- Output and type of batching/mixing plant for concreting in Construction Project
- Location of plant and materials
- Method and capacity for transporting concrete
- Decide upon equipment for compaction, finishing and curing
- Location of bar bending yard/fabrication yard
- Selecting materials control system
Also, Read: Causes, Prevention and Repair of Concrete Surface Defects
Action Before Concreting in Construction Activity:
- Obtain technical approval for the following:ย
- Materials including mix design and sample panel
- Temporary works design
- Tolerances
- Method and sequence of working
- Before Concrete Production:
- Calculate batch weights for concretingย
- Arrange materials for concreting in construction
- Arrange connection of services
- Arrange to provide a construction plant
- Obtain testing equipment
Initial Construction Setup After Site Occupation:
- Establish a communication system
- Erect. calibrate and commission concrete production plant
- Connect water and power supply
- Construct workshop and storage facilities
- Organize receipt and issue arrangements for materials
- Provide trial mixes for onsite work
- Calibrate construction equipment
- Organize spares and standby equipment
- Prepare maintenance schedule for equipment
- Establish testing facilities
- Confirm testing arrangements and compliance procedures with the clients
- Preparation of a detailed work plan for each pour, including plant, labour, materials and built-in items and testing
Also, Read: Blowholes/Surface voids/Bugholes in Concrete Surface
Pre Concreting Checks in Construction:
General Inspection Before Concreting:
- Confirm setting out has been checked
- Confirm earlier permanent work inspected
- Obtain weather forecast
- Check the adequacy of access to points of discharge and access platforms
- Confirm readiness of batching plant
- Check communications system
- Confirm compliance with safety regulations
- Confirm arrangements for transporting, placing, compacting, finishing, Curing and testing
Surfaces Check Before Concreting in Construction:
- Falsework for:
- Conformity with design
- Stability
- Rigidity
- Pre-camber
- Formwork for:
- Conformity of dimensions to within allowable tolerancesย
- Strength and rigidityย
- Correct use and number of ties
- Provision of the surface to comply with the specification
- Tightness and sealing of joints
- Final clean-up before concreting
- Arrangement for removal
Also, Read: Defects in Concrete Structure – Types – Causes and Condition Survey
Joints, Inserts and Openings Check Before Concreting in Construction:
- Construction of joints, dowels, water bars and sliding layers
- Inserts and box-outs for accuracy and security
- Fixing of stop-ends
- Arrangements for forming kickers
- Preparation of hardened surfaces
Reinforcement check before Concreting:
- Correct diameter, shape, type, location and cover
- Rigidly secured
- Surface condition
- Use of spacers, including type and size
Site Batching and Mixing of Concrete:
- Weigh scale calibration record
- Material storage facilities and availability of supplies
- Arrangement for workability control
- Batch record cards and procedure
Check During Transportation of Concrete:
- For the transportation system, check routes free from obstruction.
Also, Read: What is Pavement Quality Concrete? – PQC Construction Method
Inspection during Concreting:
During the placing of concrete:
- Adequacy of workability
- No segregation
- No movement of reinforcement or formwork
- No contamination
During compaction of concrete:
- Adequate availability of compaction equipment
- Equipment used correctly
- Adequate labour available
- Grout tightness of formwork
During finishing of concrete:
- Availability of sufficient tools
- Adequate skilled personnel available
- Access platforms in position
- Protected against physical damage
Post Concreting Checks in Construction:
Curing of Concrete:
- Concrete is adequately and continuously protected against:
- Loss of moisture
- Extremes of temperature
- Drying windsย
- Curing procedures maintained for a specified period
Also, Read: Concrete Subbase Course – DLC Construction
Removal of Formwork and Inspection:
Before removing formwork:
- Check the adequacy of concrete strength
- Identify props to be left in place
- Check safety arrangements
- Confirm arrangements for treated surface finishes and joint preparation.
- Obtain authority for removal of formwork and falsework
After removing formwork:
- Compare surface finish with specification or sample and check for defects, including:
- Segregation, honeycombing or cavities
- Cracking
- Misalignment or dimensions outside tolerances
- Physical damage from stripping
- In the event of any non-compliance:
- Decide upon possible alternative remedial measuresย
- Obtain approval for proposals
- Carry out any trials required
- Used formwork panels should be inspected properly
- Organize the collection and cleaning of all formwork and falsework itemsย
- Inspect formwork and falsework to assess suitability for further reuse
Initial Sampling and Testing for Concreting in Construction:
General Quality Control checks:
- General technical requirements from the specification for:
- Materials to be tested
- Properties to be measured
- Methods of the test to be employedย
- Rates of sampling/testing
- Test facilities
- Format for report forms
- Action to be taken in the event of non-compliance
- Open test registers
Laboratory Testing Equipment Checks:
- For site laboratory:
- Confirm building and services available at the start of the contractย
- Ensure essential equipment available
- Check equipment complies with relevant standardsย
- Check to measure equipment calibrated
Also, Read: Nondestructive Testing of Concrete – Methods & Guidelines
Construction Materials Checks:
Prior to approval:
- Technical data on proposed sources of supply
- Copies of recent test certificates
- Samples for testing as required
- Samples for testing as required
- Conduct tests required for approval
- Submit results and apply for approval
- Check the suitability of water for making concrete
After approval:
- Aggregates:ย
- Inspect each delivery to the site
- Sample from stockpiles
- Cement:
- Sample from each deliveryย
- Obtain maker’s certificate
- Sample periodically from the site store or site.
- Concrete:
- Agree on the place of samplingย
- Take a sample of adequate size for all tests
- Measure temperature
- Other materials, including reinforcement:
- Sample at agreed rates
- Obtain maker’s certificates
Also, Read: Rusting of Iron Rebar in Concrete – Special Repairing
Final Testing of Construction Material:
- For Aggregates:
- Carry out tests as required
- Submit reportsย
- Complete test register
- For Concrete:
- Carry out tests on fresh concrete as requiredย
- Prepare specimens as required for strength tests
- Cure in the manner specified
- Measure density and conduct strength tests
- Submit reports
- Complete test register
Quality Control for Concreting in Construction:
- Calculate statistical data
- Prepare quality control charts
- Recommend changes to mixes and materials if appropriate
- Undertake non-destructive tests on finished work if required.
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Article Name
Concreting in Construction - Planning and Execution
Description
Nowadays, concrete is the most used construction materials throughout the world. Before Start of Concreting in any construction, there must be proper planning and checklist which have to follow.
Author
WhiteHelmet
Publisher Name
Construction Civil
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