GUIDES
Concrete Mix Design Guides
Practical guides to strength grades, exposure categories and mix specification, grounded in ACI 211.1 and ACI 318. Each guide links through to the calculator so you can apply what you read.
All guides
Strength Grades ExplainedWhat 2500 through 6000 psi mean and where each is usedPrescriptive vs Performance-Based MixThe two ways concrete is specified under ACI 301Exposure Categories & DurabilityHow ACI 318's F/S/W/C categories can set stricter limits than strength aloneFly Ash & Slag CementSCMs, w/cm terminology, and ACI 318's F3 SCM limitsCommon Mix Design MistakesExposure, durability w/cm, tempering, and moisture correction errorsACI 318 Editions & ACI 211.1-22How the standards have evolved, conceptuallyWater-Cementitious RatioThe two w/cm ceilings and which one governsMixing Water ContentWater demand by slump and aggregate sizeCementitious ContentWater ÷ w/cm, plus ACI 318/302 minimumsCoarse Aggregate ContentDry-rodded bulk volume by size and fineness modulusFine Aggregate ContentFound by the absolute-volume methodTrial Batches & Required Strengthf′cr and ACI 301 field trial batchesAggregate Moisture CorrectionSSD, absorption and free waterAir EntrainmentF1/F2/F3 freeze-thaw categories and target airChemical AdmixturesASTM C494 types A–G referenceThe ACI 211.1 MethodStep-by-step walkthrough of the calculationMaterial Cost CalculatorCost of concrete per yd³ from your ratesCarbon Footprint EstimatorEstimate CO2e per cubic yard from cement and SCM choices
Suggested reading order
- Set the requirements: start with the exposure and durability guide to find the ACI 318 exposure classes, maximum w/cm and minimum f′c for each element.
- Decide how the mix is specified: the prescriptive vs performance guide explains the difference between specifying proportions and specifying results.
- Choose materials: read the SCM guide (fly ash, slag cement) and the air-entrainment page if freezing and thawing applies.
- Run the ACI 211-style calculation in the calculator with your aggregate properties.
- Verify in the field: the trial-batch, moisture-correction and common-mistakes guides turn the calculation into a mix that performs.
Documents the guides refer to
- ACI 318 — building code requirements for structural concrete (durability classes, acceptance).
- ACI 211.1 — the classic proportioning procedure for normal-weight concrete.
- ACI 301 — specifications for concrete construction.
- ASTM C33, C150, C595, C618, C989, C494, C260 — aggregates, cements, fly ash, slag cement and admixtures.
- ASTM C143, C231, C31, C39 — slump, air content, making and testing cylinders.
Check the editions adopted by your local building code and project specification.
Frequently asked questions
Are these guides a substitute for the standard?
No. These guides explain the concepts in plain language, but the current ACI 211.1 and ACI 318 editions — and your project specification — are always the reference for a real project.
Do I need to be an engineer to use them?
No. They are written to be useful to practising engineers as well as contractors and students who need a clear explanation of a term or a step.