ACI 301 Mix Designer ™ — Standard Operating Procedure

When to Use: Standard prescriptive submittals or state/municipal projects where lab trial batches and curves are not requested.

Procedure in Software:

1. In Step 2, check Manual Mix Proportioning (ACI 211 Absolute Volume).
2. Enter your target Design Water (lbs/yd³), Coarse Aggregate 1 & 2 weights, SCM replacement percentage, and projected break strengths.
3. Keep "Hide 1-2-3 Trial Columns on Submittal Report" CHECKED.

Submittal Output: Generates a clean, single-page submittal packet displaying only the Mix (Proposed) column, specific gravities, air/slump specifications, and exact 27.000 cu. ft. yield balance. Trial batch columns and graph boxes are omitted.

When to Use: When the project structural engineer demands an official ACI 301 3-point strength curve for approval, but the QC Director wants exact control over final production batch weights, mixing water, and sand yield rather than computer interpolation.

Procedure in Software:

1. In Step 2, check Manual Mix Proportioning (ACI 211 Absolute Volume) and enter your custom production batch weights.
2. UNCHECK "Hide 1-2-3 Trial Columns on Submittal Report".
3. Ensure Trial Batches 1, 2, and 3 contain your baseline lab qualification test data.

Submittal Output: Generates a complete 4-column submittal (Trial 1, Trial 2, Trial 3, and Proposed Mix) with the ACI 301 Compressive Strength Curve Graph. The 3d, 7d, and 28d curves are plotted from the trial batches, and your custom proposed mix is plotted as the highlighted red diamond marker (◆) at your target W/Cm and projected strength.

When to Use: Official qualification testing for new mix designs where 3 laboratory trial batches are mixed at varying water-cementitious ratios to establish compliance.

Procedure in Software:

1. In Step 2, leave Manual Mix Proportioning UNCHECKED.
2. Input 3 laboratory trial batches spanning your required overdesign strength (f'cr): Point 1 (High W/CM), Point 2 (Mid W/CM), and Point 3 (Low W/CM).
3. Adjust the Target W/CM slider to hit your required f'cr.

Submittal Output: The system calculates polynomial regression (R²) curves through the 3 trials and mathematically interpolates the proposed batch weights and strengths. The submittal report prints all 3 trials, the interpolated proposed mix, and the regression graph.

When to Use: Active concrete plants with existing break records. This is the most cost-effective and structurally defensible method because it uses real-world plant test records instead of paying for laboratory trial batches.

Procedure in Software:

1. In OnlineQC, select 3 companion historical mixes with consecutive break records.
2. OnlineQC statistically calculates plant standard deviation (s), modification factor (k), and required overdesign (f'cr).
3. Click "Generate 3-Point Curve / Send to Mix Designer".
4. The companion mix points, actual plant batch weights, and field break averages are automatically ingested into the ACI 301 Mix Designer.

Submittal Output: The Designer plots the 3-point field production curve, determines the permissible maximum W/Cm required to satisfy f'cr, and proportions the proposed production mix with full statistical documentation.

In the Design Targets panel of the Mix Designer, input:

• Specified Strength (f'c): e.g., 4,000 psi.
• Slump Target: e.g., 4.0 inches.
• Max Aggregate Size: e.g., #57 Stone (1.0" or 0.75").
• Air Entrainment: Choose Non-Air Entrained (1.5%) for interior flatwork, or Air-Entrained (6.0%) for exterior exposure.

ACI 301 / ACI 318 requires an overdesign buffer based on the plant's standard deviation (s):

• If standard deviation (s) is known from 30+ tests: f'cr = f'c + 1.34s (or f'cr = f'c + 2.33s − 500).
• If no statistical record exists: For f'c = 3,000 to 5,000 psi, add +1,200 psi overdesign (f'cr = 5,200 psi).

Set mixing water (typically 270 – 305 lbs/yd³ for mid-range WR, or 320 – 340 lbs/yd³ without water reducers). Select the target W/CM based on strength table or curve:

• 4,000 psi target → W/CM ≈ 0.45 to 0.50
• 5,000 psi target → W/CM ≈ 0.40 to 0.44

Total Cementitious = Water (lbs) / (W/CM). For example: 280 lbs water / 0.45 = 622 lbs/yd³.

Allocate SCM replacement percentages: e.g., 20% Class F Fly Ash (124 lbs) + 80% Type I/II Portland Cement (498 lbs).

Input Coarse Aggregate Dry Rodded Unit Weight (DRUW) and Sand Fineness Modulus (FM ≈ 2.65 – 2.80). The app automatically computes dry coarse aggregate weight and balances the remaining cubic feet with sand.

Configure dedicated Air Entraining Admixture (ASTM C260) (e.g., Sika Air, AEA-92, Daravair) plus up to four independent Chemical Admixtures (ASTM C494 Types A through S). This aligns 1:1 with OnlineQC batch proportions, ensuring seamless synchronization between batch plant production records and engineering submittals.

Batch three distinct mixes spanning across your target required strength (f'cr):

• Point 1 (High W/CM / Low Strength): e.g., W/CM = 0.55 → 28-Day break ≈ 3,900 psi
• Point 2 (Medium W/CM / Mid Strength): e.g., W/CM = 0.46 → 28-Day break ≈ 5,200 psi
• Point 3 (Low W/CM / High Strength): e.g., W/CM = 0.38 → 28-Day break ≈ 6,600 psi

In the 3-Point Curve Verification section of the studio, enter the W/CM and 28-day cylinder break results for Points 1, 2, and 3.

The system calculates linear regression: Strength = Slope × (W/CM) + Intercept and determines the exact Maximum Allowable W/CM required to achieve your f'cr.

Click "Apply Curve W/C to Mix". The app automatically updates your batch cementitious content and rebalances absolute volume for submittal generation.

To save your active mix proportions for future jobs:

1. Click the "💾 Save" button in the top navigation bar.
2. Enter a unique Mix Code (e.g., FB-4000-FA-AIR) and descriptive name.
3. Your mix is instantly saved to your browser session and automatically synced with your central Supabase Cloud Database under your active producer portal (e.g. Felton Brothers).

Use "Export" to download a backup file of all customer mix designs. Use "Import" on another workstation or laptop to load an entire mix catalog in one click.

1. Click the "Submittal Preview" tab at the top.
2. Verify Project Name, General Contractor, Architect/Engineer, Plant Location, and Mix Code.
3. Review the complete Batch Weights Summary (SSD and Dry), Absolute Volume Table, and ACI 301 Compliance Box.

1. Click "🖨️ Print".
2. In your browser print dialog, ensure:
   • Destination: Save as PDF (or select printer).
   • Layout: Portrait.
   • Margins: Default or Minimum.
   • Background Graphics: Checked / Enabled.
3. Click Save to generate your official, professional ACI 301 Concrete Mix Design submittal ready for engineer approval.