CostBuildrHow Much Sand and Crush for Concrete
Sand and crush (coarse aggregate) make up the bulk volume of concrete—about 85% of the total. Getting these quantities right ensures your concrete mix achieves its design strength and you don't face mid-pour shortages. This guide shows you how to calculate sand and crush for any concrete volume and mix ratio.
The Calculation Method
Start with the wet volume of concrete needed. Multiply by 1.54 to get dry volume. Then apply the ratio. For 1:2:4 (total 7 parts): sand = dry volume × 2/7; crush = dry volume × 4/7. For 1:1.5:3 (total 5.5 parts): sand = dry volume × 1.5/5.5; crush = dry volume × 3/5.5.
Example: 100 cft wet concrete at 1:2:4. Dry volume = 154 cft. Sand = 154 × 2/7 = 44 cft. Crush = 154 × 4/7 = 88 cft. At 1:1.5:3: sand = 154 × 1.5/5.5 = 42 cft, crush = 154 × 3/5.5 = 84 cft. The stronger mix uses slightly less aggregate because the cement paste fills more of the voids.
Sand and Crush Quantities per Bag of Cement
A useful shorthand: for every bag of cement, you need a fixed amount of sand and crush based on the ratio. At 1:2:4: per bag (1.25 cft cement) → sand = 2.5 cft, crush = 5 cft. At 1:1.5:3: per bag → sand = 1.875 cft, crush = 3.75 cft.
This per-bag method is popular on small sites. If you know you need 48 bags of cement at 1:2:4: sand = 48 × 2.5 = 120 cft, crush = 48 × 5 = 240 cft. These are nominal volumes—order 10% extra to account for moisture content, settlement in the pile, and mixing losses.
Quality and Procurement Tips
Use clean, well-graded sand (Zone II or III per IS/BS standards). Dirty sand with clay or silt content above 5% reduces concrete strength by up to 25%. The simple field test: squeeze a handful of wet sand—if it stains your palm yellow or brown, it contains too much clay.
Crush should be angular with a maximum size of 20 mm for slabs and 12 mm for columns with closely spaced steel. Rounded river gravel can be used but requires slightly more cement for the same strength. In Pakistan, crush is sold by the truck load (typically 200–250 cft per truck). Sand is sold similarly at 200–300 cft per truck. Prices range from PKR 40,000–80,000 per truck load depending on quality and location.
常见问题
How much sand per bag of cement for 1:2:4 concrete?
2.5 cubic feet of sand per 50 kg bag of cement. So for 10 bags of cement at 1:2:4: 25 cft of sand and 50 cft of crush.
What is the difference between sand and crush in concrete?
Sand (fine aggregate, < 4.75 mm) fills the gaps between crush particles. Crush (coarse aggregate, 5–20 mm) provides the structural bulk. Both are essential—concrete with only sand would shrink excessively; concrete with only crush would have voids and be weak.
How many truck loads of sand for a house?
A two-story 5 marla house needs roughly 3,000–4,000 cft of sand total (for concrete, mortar, and plaster). At 250 cft per truck: 12–16 truck loads. Order in phases—store only what you'll use in 2–3 weeks to prevent contamination and theft.