Coarse Gravel and Rock Quantity Formula |
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\( Q_{co} \;=\; \dfrac{ r_{co} }{ T } \cdot V \) (Coarse Gravel and Rock Quantity) \( r_{co} \;=\; \dfrac{ Q \cdot T }{ V }\) \( T \;=\; \dfrac{ r_{co} \cdot V }{ Q }\) \( V \;=\; \dfrac{ Q \cdot T }{ r_{co} }\) |
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| Symbol | English | Metric |
| \( Q_{co} \) = Coarse Quantity (Gravel and Rock) | \(dimensionless\) | \(dimensionless\) |
| \( r_{co} \) = Coarse Ratio | \(dimensionless\) | \(dimensionless\) |
| \( T \) = Total Ratio of Ingredients | \(dimensionless\) | \(dimensionless\) |
| \( V \) = Concrete Volume | \(ft^3\) | \(m^3\) |
Coarse gravel and rock quantity is the amount of coarse aggregates, typically consisting of gravel, crushed stone, or other rock materials, used in construction applications like concrete or road base. These aggregates, ranging in size from about 4.75 mm to 75 mm, provide structural strength and stability to concrete mixes. The quantity required depends on the mix design, which is tailored to the desired concrete properties, such as compressive strength, workability, and durability, as well as the project’s specifications.
For instance, in a standard concrete mix with a ratio of 1:2:4 (cement:sand:coarse aggregate), coarse gravel and rock constitute the largest portion, often around 50-60% of the total volume. For one cubic meter of concrete, the coarse aggregate quantity typically ranges from 800 to 1200 kg, depending on the mix grade, aggregate size, and shape (angular or rounded). The exact amount is calculated based on the volume of concrete needed, the specific gravity of the aggregates (usually 2.6-2.8), and adjustments for factors like water content or admixtures.
Proper sizing and grading of coarse gravel and rock are critical to minimize voids and ensure a dense, strong concrete matrix. Variations in quantity may arise due to regional material availability, project requirements (e.g., high-strength concrete for bridges or standard concrete for pavements), or environmental conditions affecting aggregate properties. Accurate estimation of coarse gravel and rock quantity is essential to achieve cost-efficiency, structural performance, and compliance with standards like ASTM or IS codes.
