# What is Aggregate Density kg m3?

In the process of building concrete, aggregates are essential because they enhance the final product’s strength and durability. Aggregate density is also known as unit weight. The normal aggregate density kg m3 lies between 1200 and 1750 (or 75 – 110 lb/ ft^3) depending on factors.

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However, aggregate density is a crucial factor that engineers and builders consider when constructing concrete mixes. Aggregate density is usually expressed in kilograms per cubic meter (kg/m3).

**What is aggregate?**

Aggregates are inert materials mixed with a binding material (cement, lime, sand, gravel, crushed stone, slag, or other material) in the preparation of mortar or concrete. The most mined material in the world, aggregate serves as a filler and provides concrete strength.

It may be natural, manufactured, or recycled. Aggregates make up some 60-80% of the concrete mix. Aggregates in any particular mix of concrete are selected for their durability, strength, workability, and ability to receive finishes.

**Classification of aggregates**

**According to source:**

**Natural aggregate:**The aggregates are found in natural sources like river basins, sea beds, slope deposits. For example: Gravel, sand**Crushed rock aggregate:**This aggregate is formed by crushing the various rocks obtained from quarries. For example: stone aggregates**Artificial aggregate:**The aggregate is made up of various waste materials. For example: burnt clays, artificial cinders, steel rivet, iron ore, etc.**Recycled aggregate:**This aggregate is manufactured by crushing inert construction and demolition waste.

**According to surface texture:**

- Glassy
- Smooth
- Rough (Hard to compact)
- Honeycombed(porous)

**According to size of aggregates:**

**Fine aggregates:**The aggregate having a size of particles less than 4.75m, is called a fine aggregate.

Fine Aggregate | Size |

Coarse sand | 2.0mm-0.5mm |

Medium sand | 0.5mm-0.25mm |

Fine sand | 0.25mm-0.06mm |

Silt | 0.06mm-0.002mm |

Clay | <0.002 |

**Coarse aggregates:**The aggregates having a size of particles more than 4.75mm are called coarse aggregates.

Coarse Aggregate | Size |

Fine gravel | 4mm-8mm |

Medium gravel | 8mm-16mm |

Coarse gravel | 16mm-64mm |

Cobbles | 64mm-256mm |

Boulders | >256mm |

**All in one aggregate:**The aggregate containing both fine and coarse aggregates is called as all in one aggregate.

**According to shape:**

Classification | Description | Example |

Rounded | Fully water-worn or completely shaped by striation | River or seashore gravels desert, seashore, and wind-blown sand |

Irregular | Naturally irregular or party-shaped by attrition, having rounded edges | Pit sands and gravels, land or dug fruits, cuboid rock |

Angular | Possessing well-defined edges formed at the intersection of roughly planar faces | Crushed rocks of all types, talus, screes |

Flaky | Material, usually angular, of which the thickness is small relative to the width and/ or length | Laminated rocks |

Elongated | When the length of the aggregate is larger than the other two dimensions or greater than 18% of its dimension. |

**According to weight:**

Type of Aggregate | Unit weight (kg/m^{3}) | Example |

Lightweight | <1120 | Synthetic aggregates |

Normal Weight | 1520-1680 | Most of natural aggregates |

Heavyweight | >2080 | Aggregates obtained from barium minerals, iron, titanium ores, etc |

**What is aggregate density?**

The density is commonly used in construction to know the weight of material. The density is represented by the (p). Generally, the ranges between 1200 and 1750 kg/m3 (or 75 – 110 lb/ ft^3). Normally the density depends on several conditions like size, wet, dry, and loose. Now, we calculate the aggregate density kg/m3 through retavie and the bulk density.

**Aggregate Density**=Relative Density (Specific Gravity) of Aggregate×Density of Water

**What is mass?**

It is the amount of matter contained in a substance.

**Common unit**=kg & grams

**Mass=**8,500 gms

**What is volume?**

Volume is the quantity of three-dimensional space enclosed by a close surface.

**Common unit**= meter & cm

**Volume**= Length x Width x Height

=15 X15 X15

= 3,37cm^{3}

**What is the density?**

Density is a measure of the mass of an object per unit volume.

**Common unit**= kg/m^{3 }& gm/ cm^{3}

**Density Formula:**

**Ρ=Density**= mass/volume

**Density **=8,500/3,375

= 2.5185 gm/ cm^{3}

**What is the density of the particles aggregate?**

The ratio of the mass or weight of an aggregate particle to its own volume is called particle aggregate density. It is also known as the mass density of solids.

**Common Unit**= kg/m^{3 }or g/cm^{3} or lb/ft^{3}

**Density of aggregate particle Formula: **

**Particle density=**Mass/Volume or Weight/Volume

**Density of Water: **Approximate value often used: 1000 kg/m³ (62.4 lb/ft³).

**Particle Densities for Natural Aggregates:**

Aggregate Type | Particle Density (kg/m³) | Particle Density(lb/ft³) |

Normal | 2400-2900 | 150 and 181 lb/ft³ |

Lightweight | 900-2200 | 56-137 lb/ft³ |

Heavyweight | 2500-4000 | 156-250 lb/ft³ |

**What is the Bulk density of aggregate?**

It is a ratio of its weight or mass to its volume. Density depends on the size, shape, and grading.

**Common unit**= kg/m^{3} or lb/ft3

**Formula:**

**Bulk density/Unit Weight** =weight or mass /Volume

**Common Bulk Density for Normal-Weight Concrete:**

**Range: **1200 to 1750 kg/m³ (75 to 110 lb/ft³).

**Effect of Void Content on Mix Design:**

Void contents:

- Coarse aggregates: 30% to 45%.
- Fine aggregates: 40% to 50%.

Influence on paste requirements in the mix design.

**Method of determination:**

- Standards: ASTM C 29 (AASHTO T 19).
- Methods: Rodding, jigging, shoveling

**Fine aggregate void content:**

- Standard: ASTM C 1252

**Key points: **

**Bulk density**=Mass if the volume is one unit.

**What is the Relative density or specific gravity of aggregate?**

The mass density of an object relative to the mass density of water is known as relative density. Relative density depends on volume, and mass as you assume for the aggregate particles.

**Formula:**

**Relative Density **= Mass of the Aggregate/Mass of an equal volume of water

**Range for Natural Aggregates:**

Aggregate Type | Relative Density |

Normal | 2.4-2.9 |

Lightweight | 0.9-2.2 |

Heavyweight | 2.5-4.0 |

**Test Methods:**

**Coarse aggregates:**ASTM C 127 (AASHTO T 85).**Fine aggregates:**ASTM C 128 (AASHTO T 84).

**Basis of Measurement:**

- Relative density on oven-dry or saturated surface-dry (SSD) basis.
- Both are used in concrete mix proportioning.

**Oven-Dry vs. Saturated Surface-Dry:**

**Oven-dry**: No absorbed water, constant weight in the oven.**Saturated surface-dry:**Pores filled with water, no excess on the surface.

**What is the crushed stone aggregate density?**

The density of the crushed stone aggregate depends on various factors such as size. Shape, etc. Generally, here the density is :

Aggregate | Density |

10mm aggregate | 1.6g/cm^{3} |

20mm aggregate | 1.7g/cm^{3} |

40mm aggregate | 1.8g/g/cm^{3} |

**Note:** the density also depends on moisture content, compaction, and other factors.

**Frequently Asked Questions? **

**Q.Are aggregates classified according to density?**

Yes, Lightweight, standard weight and heavyweight aggregates are the most common classifications for aggregates based on bulk-specific gravity.

**Normal-Density Aggregates:**

- Used in normal-density concrete.

**Low-Density Aggregates (Lightweight Concrete):**

- Historical term: “lightweight” concrete.
- Air-dried density at 28 days: 1440 to 1850 kg/m³ (90 to 115 lb/ft³).

**High-Density Aggregates (High-Density Concrete):**

- Used in high-density concrete.
- Density range: about 2880 to 5600 kg/m³ (180 to 350 lb/ft³).

**Reference:**

- ACI 221R and ACI 213R guide aggregate according to the type of concrete.

**Q. What is the unit density of aggregates?**

Aggregate density with a unit weight of 2200 to 2400 kg/m3 (140 to 150 lb/ft3).

**Q. What are the Relative and Bulk Density Ranges for Types of Aggregates?**

Aggregate Type | Particle size | Bulk Density | Relative density |

Fine Aggregate Density | ≤ 4.75mm | 1,400 to 1,800 kg/m³ (87 to 112 lb/ft³) | 2.4-2.9 |

density of coarse aggregate | 4.75mm-37.5mm | 1,350 to 1,650 kg/m³ (84 to 103 lb/ft³) | 2.4-2.9 |

Medium Aggregate | 4.75mm-19mm | 1,400 to 1,800 kg/m³ (87 to 112lb/ft³) | 2.4-2.9 |

Lightweight Aggregate | 4.75mm-37.5mm | 800 to 1,400 kg/m³ (50 to 87 lb/ft³) | 0.9-2.2 |

Heavyweight Aggregate | 4.75mm-37.5mm | 2,500 to 4,000 kg/m³ (156 to 250 lb/ft³) | 2.5-4.0 |

**Wrapping Up: **

Hopefully, you understand the aggregate density kg m3. To build long-lasting and solid concrete, one is required to be aware of the standard density values for both normal-weight and lightweight particles. In a variety of building applications, establishing a suitable strength, workability, and durability can be made easier by the careful selection of aggregates based on their density.