# Concrete and Masonry

## Concrete Fundamentals

### Mix Design
| Strength (psi) | Use |
|----------------|-----|
| 2,500 | Non-structural, fill |
| 3,000 | Residential foundations |
| 4,000 | Commercial, structural |
| 5,000 | Parking structures, exterior |
| 6,000+ | High-rise, special |

### Concrete Properties
| Property | Typical Value |
|----------|---------------|
| Unit weight | 145-150 pcf |
| Compressive strength | 3,000-6,000 psi |
| Tensile strength | 10% of compressive |
| Modulus (E) | 3,000-4,000 ksi |
| Shrinkage | 0.0005 |
| Creep | 2× elastic strain |

### Admixtures
| Type | Purpose |
|------|---------|
| Air entraining | Freeze-thaw resistance |
| Water reducer | Workability, lower w/c |
| Superplasticizer | High workability |
| Retarder | Slow setting (hot weather) |
| Accelerator | Fast setting (cold weather) |
| Fiber | Crack control |

---

## Concrete Placement

### Cover Requirements
| Exposure | Cover |
|----------|-------|
| Cast against earth | 3" |
| Exposed to earth/weather | 2" (bars #6+), 1-1/2" (bars #5-) |
| Not exposed to weather | 1-1/2" (slabs), 1" (walls) |
| Fire-rated | Per assembly |

### Rebar Spacing
| Element | Max Spacing |
|---------|-------------|
| Walls | 18" or 3× thickness |
| Slabs | 18" or 3× thickness |
| Footings | 18" |
| Temperature steel | 5× thickness or 18" |

### Consolidation
| Method | Slump Range | Use |
|--------|-------------|-----|
| Vibration | 2"-5" | Standard |
| Self-consolidating | 8"+ | Congested, complex |
| Rodding | 2"-4" | Test cylinders |

---

## Concrete Joints

### Joint Types
| Type | Purpose | Spacing |
|------|---------|---------|
| Contraction (control) | Crack control | 24-36× thickness |
| Expansion | Movement | 200' max, at changes |
| Construction | Pour breaks | Planned locations |
| Isolation | Separate elements | At columns, walls |

### Contraction Joint Depth
```
Depth = 1/4 × slab thickness (min)
       = 1/3 × slab thickness (preferred)

Example: 4" slab → 1" deep joint minimum
```

### Joint Spacing
| Slab Thickness | Max Spacing |
|----------------|-------------|
| 4" | 8'-10' |
| 5" | 10'-12.5' |
| 6" | 12'-15' |

---

## Slab-on-Grade

### Components
```
Top to bottom:
1. Concrete slab (4"-6")
2. WWF or fiber reinforcement
3. Vapor barrier (6 mil min)
4. Granular base (4" compacted)
5. Compacted subgrade
```

### Floor Flatness Standards
| Use | FF | FL |
|-----|----|----|
| Random traffic | 25 | 20 |
| Warehouse (conventional) | 35 | 25 |
| Warehouse (VNA) | 50 | 50 |
| Superflat | 100 | 100 |

### Finishes
| Finish | Method | Use |
|--------|--------|-----|
| Broom | Textured | Exterior, ramps |
| Float | Smooth | Under flooring |
| Trowel | Hard, smooth | Exposed, warehouse |
| Polish | Ground, sealed | Decorative |
| Stamped | Patterned | Decorative |

---

## Reinforcement

### Rebar Sizes
| Bar # | Diameter | Area (sq in) | Weight (lb/ft) |
|-------|----------|--------------|----------------|
| #3 | 3/8" | 0.11 | 0.376 |
| #4 | 1/2" | 0.20 | 0.668 |
| #5 | 5/8" | 0.31 | 1.043 |
| #6 | 3/4" | 0.44 | 1.502 |
| #7 | 7/8" | 0.60 | 2.044 |
| #8 | 1" | 0.79 | 2.670 |

### Welded Wire Reinforcement
| Designation | Wire Size | Spacing |
|-------------|-----------|---------|
| 6×6-W2.9×W2.9 | W2.9 (10 ga) | 6"×6" |
| 6×6-W4.0×W4.0 | W4.0 (8 ga) | 6"×6" |
| 4×4-W4.0×W4.0 | W4.0 (8 ga) | 4"×4" |

### Splice Lengths
| Condition | Splice Length |
|-----------|---------------|
| Tension (Class B) | 1.3 × development |
| Compression | 0.0005 × fy × db min 12" |
| Lap (typical) | 40-60× bar diameter |

---

## CMU (Concrete Masonry Unit)

### Standard Sizes
| Nominal | Actual | Use |
|---------|--------|-----|
| 4×8×16 | 3-5/8×7-5/8×15-5/8 | Veneer, non-load |
| 6×8×16 | 5-5/8×7-5/8×15-5/8 | Interior partitions |
| 8×8×16 | 7-5/8×7-5/8×15-5/8 | Standard load-bearing |
| 10×8×16 | 9-5/8×7-5/8×15-5/8 | Taller walls |
| 12×8×16 | 11-5/8×7-5/8×15-5/8 | Tall/heavy walls |

### Unit Types
| Type | Weight | Strength | Use |
|------|--------|----------|-----|
| Normal | 130-140 pcf | 1,900+ psi | Structural |
| Lightweight | 85-105 pcf | 1,900+ psi | Lighter loads |
| Medium weight | 105-130 pcf | 1,900+ psi | Balance |

### Special Shapes
| Shape | Use |
|-------|-----|
| Bond beam | Horizontal reinforcement |
| Lintel | Over openings |
| Pilaster | Column/reinforcement |
| Bullnose | Rounded corners |
| Screen block | Decorative, ventilation |

---

## CMU Wall Design

### Wall Reinforcement
| Application | Vertical | Horizontal |
|-------------|----------|------------|
| Standard | #5 @ 48" O.C. | Bond beam every 4' |
| Enhanced (wind) | #5 @ 32" O.C. | Bond beam every 4' |
| High wind/seismic | #5 @ 24" O.C. | Bond beam every 4' |

### Grouting
| Type | Description |
|------|-------------|
| Solid grouted | All cells filled |
| Partial grout | Cells at rebar only |
| Fine grout | Small cells, aggregate < 3/8" |
| Coarse grout | Large cells, aggregate ≤ 1/2" |

### Control Joints
| Location | Spacing |
|----------|---------|
| Max O.C. | 20'-25' (depends on L/H) |
| At openings | Within 4' of corners |
| At changes | Height, thickness changes |
| At intersections | Control joint one side |

---

## Mortar and Grout

### Mortar Types
| Type | Strength | Use |
|------|----------|-----|
| M | 2,500 psi | Below grade, severe |
| S | 1,800 psi | Structural, wind/seismic |
| N | 750 psi | Above grade, moderate |
| O | 350 psi | Non-structural, interior |

### Mortar Mix Proportions
| Type | Portland | Lime | Sand |
|------|----------|------|------|
| M | 1 | 1/4 | 3-3.75 |
| S | 1 | 1/2 | 4-4.5 |
| N | 1 | 1 | 5-6 |

### Grout Strength
| Application | Min Strength |
|-------------|--------------|
| Standard | 2,000 psi |
| Structural | 2,500+ psi |

---

## Brick Masonry

### Standard Sizes
| Type | Nominal | Actual |
|------|---------|--------|
| Modular | 4×2-2/3×8 | 3-5/8×2-1/4×7-5/8 |
| Standard | 4×2-2/3×8 | 3-3/4×2-1/4×8 |
| King | 4×3×10 | 3×2-3/4×9-5/8 |
| Norman | 4×2-2/3×12 | 3-5/8×2-1/4×11-5/8 |

### Bond Patterns
| Pattern | Description |
|---------|-------------|
| Running | Staggered, standard |
| Stack | Vertical alignment |
| Flemish | Alternating headers |
| English | Alternating courses |
| Herringbone | Diagonal, paving |

### Expansion Joints
| Material | Spacing |
|----------|---------|
| Clay brick | 20'-25' |
| Concrete brick | Not recommended (shrink) |

---

## Lintels and Openings

### Lintel Types
| Type | Span | Material |
|------|------|----------|
| Steel angle | 4'-8' | L4×3×1/4 typical |
| Steel plate | 2'-4' | 1/4" × 6" |
| Reinforced CMU | 4'-10' | Bond beam |
| Precast | 4'-12' | Precast lintel |

### Bearing Requirements
| Lintel Type | Min Bearing |
|-------------|-------------|
| Steel | 4" each end |
| Reinforced masonry | 8" each end |
| Precast | 4" each end |

### Opening Reinforcement
- Horizontal bar above opening
- Vertical bars at jambs
- Additional at corners

---

## Finishes

### Concrete Finishes
| Finish | Description |
|--------|-------------|
| As-cast | Form texture |
| Bush hammer | Exposed aggregate |
| Sandblast | Textured |
| Acid etch | Light texture |
| Paint | Coating |
| Plaster/stucco | Applied finish |

### CMU Finishes
| Finish | Description |
|--------|-------------|
| Standard | Gray block |
| Split-face | Rough texture |
| Burnished | Smooth, dense |
| Glazed | Factory glazed |
| Ground-face | Polished |
| Paint | Field applied |
| Stucco | Applied plaster |

---

## Florida/Hurricane Considerations

### Wind-Resistant CMU
- Solid grouted walls
- Increased reinforcement
- Bond beams at 4' max
- Continuous vertical bars
- Anchor bolts at top

### Flood Zone Requirements
- Flood vents in stem walls
- Water-resistant materials below BFE
- No breakaway walls (unless designed)
