Construction Quality Control: Materials & Execution
Item 15 – Quality Control
Quality control in construction ensures adherence to specifications through documented procedures, including receipt control and documentation filing. It aims to prevent errors in construction stages.
Quality control involves two phases:
- Control of Materials
- Control of Execution
Key Definitions
- Departure: Number of products in a transport unit.
- Remittance: Products from one source in a transport unit.
- Collection: Stored material amount.
- Batch of Material: Material quantity received as a whole.
- Lot of Performance: Work part accepted as a whole.
- Inspection Unit: Activities for one execution process.
- Quality: Properties meeting explicit and implicit needs.
- Quality Control: Operations to meet quality requirements.
- Sample: Representative part of a lot.
- Specimen: Portion of a sample for testing.
Quality Control Agents
Optional 1-Address Quality Control
Includes project specifications, product and process control, resource forecasting, programming control, sampling responsibility, documentation system, development and validation activities, reception control, and execution control.
2-Laboratories and Quality Control Entities
3-Control Laboratories
Conduct trials for product conformity, preferably independent.
4-Quality Control Entities
Quality Control Estates
Accreditation of a Laboratory
Formal recognition.
Accreditation System
Rules for accreditation procedures.
Accreditation Body
Manages and grants accreditation.
RELAY
Spanish Network of Testing Laboratories.
ENAC
National Accreditation Board.
School Testing
- Chemical Tests: Chemical analysis, water pH.
- Physical Testing: Physical properties, cement expansion.
- Mechanical Testing: Bending, tensile, compression.
- Other Tests: Employer-lab trials, destructive (concrete breakage), non-destructive (elastomers).
Concrete Testing Equipment
- Moulds: Shape specimens.
- Sclerometer: Measures concrete surface hardness.
- Ultrasonic: Measures concrete uniformity.
- Presses: Apply force to measure load until specimen break.
Additives and Additions
Additives: Substances added to concrete (max 5%) to change features. Requires document verification or test certificate.
Additions: Inorganic materials (fly ash, silica fume) added to improve properties. Requires suitability justification.
Concrete Control
Includes documentary and experimental proof. Supply sheets are mandatory for concrete use.
Consistency Control Types (Seats)
Dry (0-2), plastic (3-7), soft (8-12), fluid (13-18), liquid (cm).
Durability Control
Ensures performance against degradation. Includes verifying water-cement ratio, cement content, compaction, and curing.
Resistance of Concrete
- 15x30cm cylindrical samples.
- 15cm cubic specimens.
- 10cm cubic specimens (if aggregate size is <12mm).
Specimens kept on-site for 16 hours to 3 days before testing.
Concrete Control Methods
- Statistical Control: Dividing work into batches.
- Control 100: Measuring all batches.
- Indirect Control (NDT): For minor, non-structural concrete.
Test Characteristics
Real resistance feature of concrete is placed over the project. Six batches per dosage, with two samples per batch for compression fracture testing after 28 days.
Testing Information
Required when acceptance criteria are breached or doubts arise. Includes specimen making and breaking, witness specimen rupture (if possible), and non-destructive methods (sclerometer, ultrasound).