Concrete Overview Building Codes & Rules

- Get concrete right the first time. Use our Concrete Overview Tool™ to follow key NCC rules for testing, pouring, vibrating, and curing concrete safely.

Industry Recommendation

AS 3600:2018, 19.1

NCC 2022 HP, 4.2.8

Pre-Pour Preparation^{Industry Recommendation}

Site cleared, levelled, & compacted per soil classification
Verify formwork stability, dimensional conformity & _ elevation accuracy
Reinforcement placed with correct cover support
Conduct reinforcement inspection hold points (position, tying, cleanliness, cover) to prevent damage
Check placement of construction, movement & isolation joints^{Industry Recommendation}
Vapour barrier correctly installed as per NCC requirements^{Industry Recommendation}

Pour & Placement^{AS 3600:2018, 19.1}

Confirm delivery docket & concrete mix design conform to Engineer's Specifications
Place concrete vertically & evenly close to its final position to prevent segregation
Shovel concrete into place & avoid letting it flow
For deep forms, prevent concrete from ricocheting off rebar/forms by controlling drop height
Ensure formwork & reinforcement is not displaced & damaged during pour
Cover fresh concrete with secured impermeable sheeting & manage surface runoff to prevent contact with the rainwater
Avoid concreting during or before anticipated heavy rain

Vibration & Compaction^{NCC 2022 HP, 4.2.8}

Vibration removes air voids, compacting concrete to enhance strength & durability
Initial vibration liquefies the concrete, allowing for efficient void release
Optimal compaction is achieved when surface air bubbles cease to appear
Proper re-vibration can improve bond & finish, but excessive vibration leads to segregation & honeycombing

Concrete Testing

Compressive Strength Test^[1]
Conducted at 7, 14, & 28 days
1 test per 20 to 50m³ of concrete placed
Slump Test^[2]
Performed at the start of each pour

Other Methods of Fresh Concrete Testing

NCC 2022 V1

Industry Recommendation

Different routine tests on fresh concrete assess its consistency, workability & measure distinct parameters, results are not directly comparable, & one test's outcome cannot validate compliance based on another's specification^{Industry Recommendation}

Slump Test COMPLIANCE

NCC 2022 V1

AS 1379:2007, 5.2.2

AS 1379:2007, 5.2.1

AS 1379:2007, 4.2.3

AS 1379:2007, 5.2.4

AS 1379:2007, 5.2.3

Conducted in accordance with AS 1012.3.1^{AS 1379:2007, 5.2.2}
Mandatory on each strength sample when a strength grade is specified^{AS 1379:2007, 5.2.1}
If slump is the primary compliance criterion, its sampling frequency must be explicitly specified^{AS 1379:2007, 4.2.3}
If initial slump fails, one repeat test is performed immediately^{AS 1379:2007, 5.2.4}
Concrete is compliant if the measured slump falls within Slump Tolerance per table below^{AS 1379:2007, 5.2.3}

Other Methods of Hardened Concrete Testing

NCC 2022 V1

Industry Recommendation

Various tests from simple to complex are performed on hardened concrete to assess its properties & service performance, utilizing both non-destructive & destructive methods with varying timeframes^{Industry Recommendation}

Slump Test REQUIREMENTS

NCC 2022 V1

Manufacturer's Requirement

Testing carried out in accordance to AS 1012.3.1^{Manufacturer's Requirement}
Determines the slump consistency & workability of fresh concrete, typically for mixes with nominal aggregate size ≤ 40mm^{Manufacturer's Requirement}
Apparatus^{Manufacturer's Requirement}
Slump Cone: 200mm base, 100mm top, 300mm height, smooth, non-absorbent, unreactive & rigid ≥ 1.5mm thk galvanised steel sheet
Rod: Ø 16mm, 600mm long, rounded end
Scoop: For placing concrete
Base plate: Smooth, horizontal, non-vibrating
Measuring device: Ruler or tape measure
Procedure^{Manufacturer's Requirement}
Clean/moisten cone & base plate
Fill cone in 3 equal layers, overfilling the top
Rod each layer 25 times with the rounded tamping rod to ensure full compaction & overfill the top layer
Strike off excess concrete flush with the cone's top
Lift cone vertically 3 ±1 seconds without displacement
Immediately measure slump (300mm - specimen height) to nearest 5mm (for ≤100mm) or 10mm (for >100mm)
Test Validity^{Manufacturer's Requirement}
Entire procedure must be completed within 3 minutes
Invalid if specimen collapses or shear
Record^{Manufacturer's Requirement}
Identification of Test Specimen
Date
Measured Slump (mm)
Shear or Lateral Collapse

Concrete Test Frequency & Compliance

NCC 2022 V1

Industry Recommendation

Testing for Quality^{Industry Recommendation}

Detailed protocols for concrete strength, workability & durability testing to AS 1012 Series
Samples taken during mixing, pouring, & curing, then verifying to AS 3600 for compliance
Generates performance data of Concrete to ensure long-term structural integrity

Frequency^{Industry Recommendation}

Large & complex projects demand higher testing frequency
High-strength or specialized concrete mixes require more frequent checks
Extreme temperatures needs increased testing due to their impact on curing & strength
High-risk structural elements mandate more stringent testing protocols
Air content & temperature tests may be required for specific environmental conditions, with frequencies determined by project needs

Compliance^{Industry Recommendation}

Obtain representative concrete samples from the batch following AS 1012 procedures
Use calibrated & maintained testing equipment
Ensure all tests are performed by trained & qualified personnel proficient in AS 1012 series
Maintain comprehensive records including test results, sample IDs, dates, & conditions, for quality assurance & compliance verification
Adhere strictly to project-specific testing requirements detailed in the concrete mix design & contract to meet performance standards

Compressive Strength Test REQUIREMENTS

NCC 2022 V1

Manufacturer's Requirement

Measures the ability of concrete to withstand compressive forces^{Manufacturer's Requirement}
Test carried out according to AS 1012.9^{Manufacturer's Requirement}
Test Specimens^{Manufacturer's Requirement}
Concerete prepared per AS 1012.8 or AS 1012.14 for cores
Age at testing, (e.g., 7, 14 & 28 days)
Cylinder Size^{Manufacturer's Requirement}
Ø100mm × 200mm (H) for ≤ 20mm aggregate size
Ø150mm × 300mm (H) for ≤ 40mm aggregate size
Apparatus^{Manufacturer's Requirement}
Compression Testing Machine calibrated per AS 2193
Procedure^{Manufacturer's Requirement}
Place specimen centrally on lower plate
Align with spherical seating block
Apply continuous, uniform load
Maintain specified stress rate (e.g., 0.2 MPa/s to 0.4 MPa/s)
Record maximum load (kN) at failure
Note type of failure
Determine Compressive Strength (MPa)^{Manufacturer's Requirement}
Computed result of Compressive Strength must be verified by the Structural Engineer
Record^{Manufacturer's Requirement}
Specimen ID, age, dimensions
Maximum load
Compressive Strength
Type of fracture
Any deviations from standard

Manufacturer's Requirement

Compressive Strength Test^{Manufacturer's Requirement}
Conducted at 7, 14, & 28 days
1 test per 20 to 50m³ of concrete placed
Slump Test^{Manufacturer's Requirement}
Performed at the start of each pour

Joints

Allow for movement in a building^[1]
Separate between different pours^[2]

Concrete JOINTS

NCC 2022 V3

All Building Classes

NCC 2022, H1D1 & 4.2.10 [2019 3.2.3.1]

May 2023

AS 3600:2018, 19.1.2

AS 3600:2018, 19.1.3

AS 3600:2018, 19.1.4

NCC 2022 HP, 4.2.10

Concrete must comply with NCC^{AS 3600:2018, 19.1.2}
Construction Joints^{AS 3600:2018, 19.1.3}
Allows easier concrete placement & finishing
Junction between different stages of pours
These do not allow movement
Located in areas that are not critical
Designed based on specific construction practices & Concrete placement requirements
Placed in areas of low shear force & minimal visibility
Spacing depends on placement rate, finishing needs, & unexpected suspension
Movement Joints^{AS 3600:2018, 19.1.4}
Allows for differential movement throughout the building's life without compromising the overall structure
Control movement at the Joint & cracking at specific locations
Spacing is crucial & considers various factors like shrinkage, temperature, & prestress (if applicable)
Contraction Joints
Controls cracking due to concrete shrinkage from curing
Joint Fillers & Sealants^{NCC 2022 HP, 4.2.10}
Fillers inserted compressed, either during concrete placement or after hardening
Sealants provide additional functionalities
Weatherproofing
Acoustic insulation
Fire resistance
Preventing material ingress
Fillers & Sealants can be used in a single Joint
Designed to prevent dirt or other materials from entering & hindering movement
Infill materials & Concrete edges need to be strong enough to prevent damage for Joints with anticipated loading

AS 3600:2018, 19.1.3.1 (c)

AS 3600:2018, 19.1.2.1

Allow for movement in a building^{AS 3600:2018, 19.1.3.1 (c)}
Separate between different pours^{AS 3600:2018, 19.1.2.1}

NCC 2022 HP, 4.2.2

NCC 2022 HP, 4.2.5

NCC 2022 HP, 4.2.11

On-site Compliance per NCC requirements

Site Classification^{NCC 2022 HP, 4.2.2}
Site has been classified in accordance with AS 2870
Helps identify common soil types
For more complex sites, use AS 2870 or ask a Structural/Geotechnical Engineer
Foundations for Footings & Slabs^{NCC 2022 HP, 4.2.5}
For Slabs, Internal Beams, Load Support Areas: ≥ 50 kPa Founded on natural soil
For Edge Beams: ≥ 50 kPa On natural soil
For Pad Footings, Strip Footings, Unconnected Edge Beams: ≥ 100 kPa On natural soil
Steel Reinforcement^{NCC 2022 HP, 4.2.11}
Such welded wire mesh (square mesh), trench mesh, steel reinforcing bars
Always check lap lengths match the drawings or standard tables

Waffle Raft Footing

Stiffened Raft Footing

Footing Slab

Concrete Curing

Wall Pour Joints

To comply with AS 3610.1 Formwork for Concrete
Indented or disguised control & Construction Joints for vertical surfaces

Indented Horizontal Pour Joint

NCC 2022 V3

Industry Recommendation

Crucial for managing concrete's natural movement due to factors like temperature changes & shrinkage^{Industry Recommendation}
Rebate to emphasise Joints
Use pre-formed Foam Strip on the Joint between Plywood sheets
Prevents moisture penetration
Averts Cement Grout leakage
Use Fibreglass & form liners
For textured form Joints
For complex shapes & profiles

To comply with AS 3610.1 Formwork for Concrete
Indented or disguised control & Construction Joints for vertical surfaces

Concrete Surface Finish

Threshold

Soil Classification

Formwork

Minimum Cover

Thickness of Concrete around Steel reinforcement to protect from corrosion^[1]
Ensure formwork is completelty filled large voids at the edges^[2]

Concrete COVER

NCC 2022 V5

All Building Classes

NCC 2022 4.2.11 [2019 3.2.3.2]

May 2023

AS 3600:2018, 4.10.3.2

AS 3600:2018, 4.3.1 (c)

NCC 2022 HP, 4.2.11

Concrete must comply with the NCC^{AS 3600:2018, 4.10.3.2}
Cover for standard Formwork & compaction as per table^{AS 3600:2018, 4.3.1 (c)}
Add thickness where cast against ground
Embedded elements must be protected from corrosion or deterioration^{NCC 2022 HP, 4.2.11}

AS 3600:2018, 4.3.1 (c)

AS 3600:2018, 17.1.3

Thickness of Concrete around Steel reinforcement to protect from corrosion^{AS 3600:2018, 4.3.1 (c)}
Ensure formwork is completelty filled large voids at the edges^{AS 3600:2018, 17.1.3}

Concrete Mix Specification

Normal-Class
General use^[1]
Standard compressive strength^[2]
Special-Class^[3]
Customised (e.g. severe environments)

Special Class Concrete Specification REQUIREMENTS

NCC 2022 V1

AS 1379:2007, 1.5.4

AS 1379:2007, 1.5.4 (a)

AS 1379:2007, 1.5.4 (b)

AS 1379:2007, 1.5.4 (c)

AS 1379:2007, 1.5.4 (i)

AS 1379:2007, 1.5.4 (ii)

AS 1379:2007, 1.5.4 (iii)

AS 1379:2007, 1.5.4

AS 1379:2007, 1.5.4 (A)

AS 1379:2007, 1.5.4 (B)

AS 1379:2007, B1

Any concrete requirement outside standard Normal-Class specifications^{AS 1379:2007, 1.5.4}
Strength-Grade Prefixes (when applicable)
5: Compressive strength testing is required^{AS 1379:2007, 1.5.4 (a)}
SF: Flexural strength testing is required^{AS 1379:2007, 1.5.4 (b)}
ST: Indirect-tensile strength testing is required^{AS 1379:2007, 1.5.4 (c)}
Exposure Classification Prefixes (when applicable, per AS 3600)
SB: For B2 exposure classification^{AS 1379:2007, 1.5.4 (i)}
SC: For C1 or C2 exposure classification^{AS 1379:2007, 1.5.4 (ii)}
SU: For U exposure classification^{AS 1379:2007, 1.5.4 (iii)}
Additional Requirements for SB, SC, or SU Concrete
Specify aggregate durability class per AS 2758.1^{AS 1379:2007, 1.5.4}
Adhere to relevant AS 3600 requirements^{AS 1379:2007, 1.5.4}
Concrete ≥ 50MPa strength automatically falls under special-class provisions^{AS 1379:2007, 1.5.4 (A)}
Any deviations from normal-class parameters or composition, must be specified by the customer in consultation with the supplier^{AS 1379:2007, 1.5.4 (B)}
Specification Guide for Special-Class Concrete refer to table below^{AS 1379:2007, B1}

Normal Class Concrete Specification REQUIREMENTS

NCC 2022 V1

AS 1379:2007, 1.5.3.1 (a)

AS 1379:2007, 1.5.3.1 (c)

AS 1379:2007, 1.5.3.1 (b)

AS 1379:2007, 1.5.3.1 (f)

AS 1379:2007, 1.5.3.1 (e)

AS 1379:2007, 1.5.3.1 (d)

AS 1379:2007, 1.5.3.2 (c)

AS 1379:2007, 1.5.3.2 (d)

AS 1379:2007, 1.5.3.2 (e)

AS 1379:2007, 1.5.3.2 (f)

AS 1379:2007, 1.5.3.2 (a)

AS 1379:2007, 1.5.3.2 (b)

Required Attributes
2,100 kg/m³ to 2,800 kg/m³ density^{AS 1379:2007, 1.5.3.1 (a)}
≤ 1,000 micro-strain drying shrinkage at 56 days^{AS 1379:2007, 1.5.3.1 (c)}
Conforms to specified acid-soluble chloride & sulfate content limits^{AS 1379:2007, 1.5.3.1 (b)}
No lightweight aggregate per AS 2758.1^{AS 1379:2007, 1.5.3.1 (f)}
Utilizes cement compliant with AS 3972^{AS 1379:2007, 1.5.3.1 (e)}
Mean Compressive Strength at 7 days^{AS 1379:2007, 1.5.3.1 (d)} greater than the table below
Customer-Specified Parameters
20 to 120mm Slump in 10mm increments^{AS 1379:2007, 1.5.3.2 (c)}
100mm default Slump for residential slabs/footings if not specified
10mm, 14mm, or 20mm^{AS 1379:2007, 1.5.3.2 (d)} Aggregate Size
20mm default Aggregate Size if not specified
Specify the intended placement method & equipment^{AS 1379:2007, 1.5.3.2 (e)}
Indicate if supplier-led project assessment is required^{AS 1379:2007, 1.5.3.2 (f)}
≤ 5% Air Entrainment, if required^{AS 1379:2007, 1.5.3.2 (a)}
±1.5% tolerance from specified
Compressive Strength Grade^{AS 1379:2007, 1.5.3.2 (b)} (fc′) per table below

AS 1379:2007, 1.5.1 (a) (ii)

AS 1379:2007, 1.5.1 (a) (i)

Informative

Normal-Class
General use^{AS 1379:2007, 1.5.1 (a) (ii)}
Standard compressive strength^{AS 1379:2007, 1.5.1 (a) (i)}
Special-Class^Informative
Customised (e.g. severe environments)

Strength

Characteristic Compressive Strength^[1]
Exceeded by 95% of concrete test results for a given mix

Concrete Strength RULES

NCC 2022 V1

AS 1379:2007, 5.3.1

AS 1379:2007, 5.3.3

AS 1379:2007, 5.3.4

28-Day Characteristic Strength^{AS 1379:2007, 5.3.1}
Compressive Strength tested to AS 1012
Flexural/Tensile Strength assessed via an equivalent mean compressive strength requiring:
Initial relationship established, 1 sample from 3 different compressive strength grades
Ongoing monitoring with 2 samples per production interval; re-establish if needed
≥ 2 Compressive & ≥ 3 Flexural or Tensile specimens cured & tested to AS 1012 for each every sample
Compliance
Concrete complies if AS 1379 requirements for sampling, testing & assessment are met^{AS 1379:2007, 5.3.3}
Non-compliant concrete may be accepted if^{AS 1379:2007, 5.3.4}
Supplier has a third-party audited QC system showing low results are within random variation
Supplier demonstrates non-compliance was a specific interval issue with identified causes, allowing other concrete to comply
Mutually acceptable alternative methods prove the structure's fitness for purpose
Allows acceptance of In-place Concrete ONLY, not compliance with the specified strength grade

Concrete Strength Grades of Typical Building Elements

NCC 2022 V1

AS 1379:2007, 1.3.7

Characteristic Compressive Strength^{AS 1379:2007, 1.3.7}
Exceeded by 95% of concrete test results for a given mix

Abrasion

Hardness of Concrete required to resist Abrasion^[1]

Concrete ABRASION

NCC 2022 V2

All Building Classes

NCC 2022 Part 4.2.10 [2019: 3.2.3.1]

May 2023

AS 3600:2018, 4.6

NCC 2022 HP, 4.2.10

Concrete must comply with NCC^{AS 3600:2018, 4.6}
For locations susceptible to abrasion from vehicular traffic, the compressive strength of the Concrete must surpass the values outlined in the table below^{NCC 2022 HP, 4.2.10}

AS 3600:2018, 4.6

Hardness of Concrete required to resist Abrasion^{AS 3600:2018, 4.6}

Slab Edge Rebate

Mixing & Transportation

≤1½ hours complete discharge from concrete truck upon cement hydration unless a retarder is used^[1]

Water, Admixture & Additives in Concrete Mix RULES

NCC 2022 V1

AS 1379:2007, 4.2.3

AS 1379:2007, 4.2.4

Water Addition^{AS 1379:2007, 4.2.3}
Only the supplier can add water to a mixed batch, within 75 minutes or 80% of the agreed discharge time, or whichever is greater
Operate the mixer at rated speed for at ≥ 30 revolutions for uniformity
Re-assess specified slump after remixing
Document the added water quantity if adjusted during discharge
Ensure the water-cement ratio remains within specified tolerances
Admixture & Material Addition^{AS 1379:2007, 4.2.4}
Only the supplier can add admixtures or other materials before batch discharge is complete
All additions must follow the material supplier's specifications
Operate the mixer at rated speed for ≥ 30 revolutions to re-establish uniformity, & record the type & quantity on the identification certificate
If the addition aims to modify slump, re-assess slump after remixing

Concrete Mix RULES

NCC 2022 V4

All Building Classes

NCC 2022, 4.2.10 [2019 3.2.3.1]

May 2023

NCC 2022 HP, 4.2.10

Concrete to comply with NCC^{NCC 2022 HP, 4.2.10}
Mixing & Delivery
≤ 1 ½ hrs complete discharge from Concrete truck upon Cement hydration unless a retarder is used
Compaction by vibration
To remove air pockets
Improve contact with Reinforcement & Formwork
Enhance durability
Avoid over-vibrating
Slab Edges
Proper finishing & curing of edges improves resistance to moisture damage
Chemical Curing
Determine if surface finish adhesive to be used is compatible with chemical curing methods

NCC 2022 HP, 4.2.10

≤1½ hours complete discharge from concrete truck upon cement hydration unless a retarder is used^{NCC 2022 HP, 4.2.10}

Concrete Form Finish Classes