🏗️ Concrete Mix Design — Simulink Model

ACI 211.1 | Automated, Visual, and Blazing Fast

Stop doing mix design by hand. Let Simulink do the math.

📖 Read the Docs · 🚀 Get Started · 🤝 Contribute · ⭐ Star this repo

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🔥 Why This Project?

If you've ever sat down with ACI 211.1 and a calculator, you know the pain — cross-referencing tables, computing volumes, recalculating everything when one input changes. This model eliminates all of that.

Built in MATLAB Simulink, this tool automates the full ACI 211.1 concrete mix design workflow in a clean, block-based visual environment. Change a single input — slump, target strength, aggregate size — and every downstream value updates instantly.

💡 Designed for civil engineering students, researchers, and practicing engineers
   who want fast, reliable, and reproducible concrete mix designs.

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✨ Key Features

• ⚡ Instant recalculation — Tweak any input and all outputs update in real time
• 📐 Full ACI 211.1 compliance — Water content, w/c ratio, and aggregate volumes sourced directly from ACI tables
• 🧱 3 validated concrete grades — M25, M35, and M45 scenarios included out of the box
• 🔬 Absolute Volume Method — Fine aggregate calculation encapsulated in a dedicated subsystem
• 🧩 Modular architecture — Clean, readable block layout organized left-to-right
• 📊 2-D Lookup Tables — ACI table data baked directly into the model, no external files needed
• 🎓 Perfect for learning — Ideal for coursework, labs, and understanding how mix design actually works

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📸 Model Architecture

The model is organized left-to-right: Inputs → ACI Logic (Lookup Tables + Subsystems) → Outputs

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🚀 Getting Started

Prerequisites

• MATLAB R2020b or later
• Simulink (base package)

Installation

# Clone the repository
git clone https://github.com/YOUR_USERNAME/concrete-mix-design-simulink.git

# Open MATLAB and navigate to the project folder
cd concrete-mix-design-simulink

Running the Model

% Open the model
open('ConcreteMixDesign.slx')

% Set your inputs in the Constant blocks:
%   - Target_Strength_MPa  (e.g., 25, 35, 45)
%   - Slump_mm             (e.g., 50 or 100)
%   - Max_Agg_Size_mm      (10, 20, or 40)
%   - Fineness_Modulus     (2.40, 2.60, or 2.80)

% Hit Run (Ctrl+T) — results appear in the Display blocks instantly

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📐 Methodology

The model implements the full ACI 211.1 procedure as a sequential calculation chain:

Target Strength → w/c Ratio → Cement Content
Slump + Agg. Size → Water Content ↗
Agg. Size + FM → Coarse Agg. Volume → Coarse Agg. Mass
Absolute Volume Method → Fine Aggregate Mass

Governing ACI Tables

Table 1 — Estimated Water Content (kg/m³)

Slump (mm)	10 mm Aggregate	20 mm Aggregate	40 mm Aggregate
25 – 50	215	190	175
75 – 100	225	205	185

Table 2 — Water-Cement Ratio vs. Compressive Strength

f'c (MPa)	w/c Ratio
45	0.42
35	0.52
25	0.65

Table 3 — Volume of Coarse Aggregate per m³ of Concrete

Max. Agg. Size	FM 2.40	FM 2.60	FM 2.80
10 mm	0.50	0.48	0.46
20 mm	0.66	0.64	0.62
40 mm	0.75	0.73	0.71

Cement content is derived as:

$$C = \frac{W}{(w/c)}$$

Fine aggregate fills the remaining volume after subtracting water, cement, coarse aggregate, and 2% entrapped air from 1 m³.

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📊 Results & Verification

All three scenarios share these common inputs:

Parameter	Value
Max. Aggregate Size	20 mm
Fineness Modulus	2.60
SG — Cement	3.15
SG — Fine Aggregate	2.65
SG — Coarse Aggregate	2.70
Unit Weight (CA)	1600 kg/m³
Entrapped Air	2%

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🟢 Scenario 1 — M25 Grade Concrete

Inputs: Target Strength = 25 MPa · Slump = 100 mm

Component	Result
💧 Water	205 kg/m³
🏭 Cement	315.4 kg/m³
🪨 Coarse Aggregate	1024 kg/m³
🏖️ Fine Aggregate	778.1 kg/m³

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🟡 Scenario 2 — M35 Grade Concrete

Inputs: Target Strength = 35 MPa · Slump = 100 mm

Component	Result
💧 Water	205 kg/m³
🏭 Cement	394.2 kg/m³
🪨 Coarse Aggregate	1024 kg/m³
🏖️ Fine Aggregate	690.6 kg/m³

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***

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🔴 Scenario 3 — M45 High-Strength Concrete

Inputs: Target Strength = 45 MPa · Slump = 50 mm

Component	Result
💧 Water	190 kg/m³
🏭 Cement	452.4 kg/m³
🪨 Coarse Aggregate	1024 kg/m³
🏖️ Fine Aggregate	658.5 kg/m³

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***

Validation note: As target strength increases, cement content rises and fine aggregate decreases — exactly as ACI 211.1 predicts. ✅

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🏛️ Simulink Block Architecture

Block Type	Library	Purpose
Constant	Sources	All design input parameters
2-D Lookup Table	Lookup Tables	ACI Tables 1 & 3
1-D Lookup Table	Lookup Tables	ACI Table 2 (w/c ratio)
Divide / Product	Math Operations	Cement & mass calculations
Sum	Math Operations	Absolute volume summation
Subsystem	Ports & Subsystems	Encapsulates fine aggregate logic
Display	Sinks	Output: Water, Cement, CA, FA

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🤝 Contributing

Contributions are what make open source great. Here are some ideas to get you started:

• 🔧 Extend aggregate sizes — Add support for 12.5 mm or 63 mm aggregates
• 💨 Add air-entrained concrete — Implement the ACI 211.1 air-entrained water tables
• 📈 Add a dashboard scope — Real-time plotting of proportions as inputs change
• 🌍 Metric/Imperial toggle — Auto-convert between SI and US customary units
• 🧪 Additional standards — IS 10262, BS 8500, or EN 206 mix design logic
• 📄 Report export — Generate a PDF mix design summary from the Simulink outputs

How to Contribute

# 1. Fork the repo
# 2. Create your feature branch
git checkout -b feature/air-entrained-concrete

# 3. Commit your changes
git commit -m "Add air-entrained water content tables"

# 4. Push and open a Pull Request
git push origin feature/air-entrained-concrete

Please open an Issue first for major changes so we can discuss the approach.

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📚 References

• ACI 211.1-91 — Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete. American Concrete Institute.
• MathWorks Simulink Documentation — mathworks.com/products/simulink

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📄 License

Distributed under the MIT License. See LICENSE for more information.

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If this project saved you time, please consider giving it a ⭐

Built with ❤️ for the civil engineering community