M10 Concrete — The 1:3:6 Ratio
MixDesignCalc 2026 — Complete Guide to M10 Nominal Mix: What 1:3:6 Means, Gauge Box Batching, Sand Bulking, Applications, Batch Calculator (Cement Bags, Sand & Stone), Water Control & Comparison with IS 10262 Designed M10
IS 456 Table 91 Cement : 3 Sand : 6 Stone
Gauge Box MethodBlinding PCC
DLC Sub-baseCyclopean
1:3:6
1 : 3 : 6
IS 456:2000 Table 9 — M10 Nominal Mix (by dry volume)
1
🏭 Cement
1 gauge box ≈ 50 kg bag
3
🟡 Fine Aggregate (Sand)
3 gauge boxes of sand
6
🪨 Coarse Aggregate (Stone)
6 gauge boxes of stone
Ratio is by dry volume — not by mass. One gauge box = volume of one 50 kg cement bag ≈ 35 litres.
📖 What the 1:3:6 Ratio Means
IS 456:2000 Table 9
fck = 10 MPa
The M10 nominal mix ratio 1 : 3 : 6 means for every 1 part cement by dry volume, you use 3 parts fine aggregate (sand) and 6 parts coarse aggregate (stone). It is a volume ratio, not a weight ratio — and this distinction matters enormously in practice because different materials have different densities.
The ratio is prescribed in IS 456:2000 Table 9 — the only Indian code authority for nominal mixes. This table exists for lean, plain concrete applications where strength is secondary to volume economy: blinding layers, levelling courses, dry lean concrete (DLC) sub-bases, and non-structural fills.
M10 means: characteristic compressive strength of 10 MPa at 28 days on 150mm cubes. That is the minimum strength this mix should achieve under good batching and curing conditions. In practice, well-batched M10 commonly achieves 12–16 MPa due to the conservative nature of the nominal proportions.
Cement
10%
Fine Aggregate (Sand)
30%
Coarse Aggregate (Stone)
60%
Volumetric proportions — 1 : 3 : 6
IS 456 Table 9 — Authority for This Mix
IS 456:2000 Table 9 provides nominal mix proportions for M5 through M20. The M10 row specifies 1:3:6. This mix is permitted for plain (unreinforced) concrete only — not for any reinforced concrete element regardless of loading. IS 456 Cl.9.1 prohibits nominal mix for M25 and above. M10 is the leanest structural-grade concrete in IS 456.
📦 Gauge Box (Farma) Batching — The Site Method
The gauge box (farma) is a bottomless wooden or steel box sized to the volume of one 50 kg cement bag (approximately 35 litres). Each gauge box filled with a material represents one “part” of the ratio. For M10 1:3:6, you fill: 1 gauge box cement (= 1 bag), 3 gauge boxes sand, 6 gauge boxes stone.
Gauge Box Dimensions
Standard gauge box for 1 bag (50 kg) cement:
Volume of 1 bag OPC 53 = 50 kg ÷ 1430 kg/m³ = 35.0 L
Common gauge box size:
30cm × 30cm × 39cm = 35.1 litres ✅
35cm × 30cm × 33cm = 34.7 litres ✅
40cm × 30cm × 29cm = 34.8 litres ✅
For M10 1:3:6 per batch (1 bag cement):
Cement: 1 × 35 L = 1 bag (50 kg)
Sand: 3 × 35 L = 105 L gauge boxes
Stone: 6 × 35 L = 210 L gauge boxes
Water: ~28 L (w/c ≈ 0.56) — measure; do not guess
1×
50 kg
Cement
1 bag
+
3×
35L
Sand
3 farma
+
6×
35L
Stone
6 farma
+
W
~28L
Water
Measure!
⚠ Sand Bulking — The Critical Correction
Damp sand occupies 20–30% more volume than dry sand of the same mass. This is called bulking. When you fill a gauge box with damp site sand, you get less sand by mass than intended — making the mix leaner and weaker than 1:3:6.
Sand Bulking Correction:
Bulking factor = 20–30% for typical damp river sand
Reduction in gauge box to compensate:
If bulking = 25%, fill gauge box only:
3 farma × (1 – 0.25) = 3 × 0.75 = 2.25 farma volume
= fill 75% of each farma (not full to the top)
OR:
Use 3 farma but fill only to the 75% mark
= same dry sand mass as intended
Measure bulking (IS 2386 Pt.3):
Fill 100mm of dry sand in cylinder — mark level A
Add water to saturate — level drops to B
Bulking % = (A−B)/B × 100
⚠ Ignoring Sand Bulking — The Most Common M10 Site Error
If river sand has 5% moisture (typical monsoon), bulking = ~25%. Filling 3 full gauge boxes delivers only 75% of the required sand mass — the actual ratio becomes approximately 1:2.25:6 instead of 1:3:6. The mix has too little sand: harsher, less workable, and the cement-sand ratio shifts unfavourably. Check bulking monthly or whenever sand source changes. In monsoon: check daily.
← Scroll
| Sand Moisture (%) | Typical Bulking (%) | Gauge Box Fill Level |
|---|---|---|
| 0% (completely dry) | 0% | Fill to the top (100%) |
| 2–3% (slightly damp) | 10–15% | Fill to 88–90% |
| 4–6% (normal damp) | 20–28% | Fill to 72–80% |
| 8–10% (wet river sand) | 25–30% | Fill to 70–75% |
| Saturated (flooded) | 0% (sand slumps) | Fill to the top |
⚡ M10 (1:3:6) Batch Quantity Calculator
Calculate Cement Bags, Sand & Stone
📊 Typical Quantities per m³ — M10 1:3:6
← Scroll
| Parameter | 1:3:6 Nominal (Nominal) | IS 10262 Designed M10 | Notes |
|---|---|---|---|
| Cement | 210–230 kg/m³ (4.2–4.6 bags) | 185–205 kg/m³ (3.7–4.1 bags) | Designed mix uses less cement |
| Fine Aggregate (Sand) | 630–690 kg/m³ | 680–720 kg/m³ | More sand in designed mix |
| Coarse Aggregate (Stone) | 1260–1380 kg/m³ | 1210–1300 kg/m³ | 40mm MSA designed saves water |
| Water | 180–220 L/m³ (site variable) | 172–188 L/m³ (controlled) | Nominal has no w/c control |
| Approx w/c | 0.75–0.95 (variable) | 0.70–0.80 (designed) | Nominal w/c uncontrolled on site |
| Fresh density | 2280–2500 kg/m³ | 2300–2420 kg/m³ | |
| fck achieved | 10–16 MPa | 10–13 MPa (targeted) | Nominal over-achieves due to extra cement |
| Trial mix needed? | No | Yes — IS 10262 Cl.7 |
🔧 Applications of M10 (1:3:6)
🪨
Blinding Layer (PCC)
50–75mm below RCC foundations, raft slabs, pile caps. Clean working surface for rebar. Prevents contamination. Most common M10 use.
🛣️
DLC Sub-base (IRC:SP:49)
100–150mm roller-compacted pavement sub-base. Very low slump (15–25mm). 7-day strength ≥ 10 MPa. Do not vibrate — roll with vibratory roller.
📐
Levelling / Bedding
Under precast elements, equipment bases, steps. 25–50mm layer. Provides level, stable bearing surface. Self-level by tamping.
🏔️
Cyclopean Concrete
M10 base + 20–40% rubble/plum stones (IS 456 Cl.8.2.6). Gravity retaining walls, dam toes, mass fills. Major cement economy.
🌿
Garden / Landscape
Pathways, kerbs, garden borders, flower-bed edging, step treads in non-public low-traffic areas. Not for wearing surfaces.
🔵
Trench / Pipe Bedding
Concrete surround for drainage pipes, cable ducts, gas lines. Provides mechanical protection and stable bedding in trench.
⚠ What M10 Is NOT Suitable For
M10 must not be used for: any reinforced concrete element (IS 456 Cl.6.1.2 requires M20 minimum for Mild RCC); any load-bearing column, beam, or slab; any structure in Moderate, Severe or higher exposure (IS 456 Table 5 requires M25 minimum for Moderate RCC); any structural retaining wall (only the mass gravity plain concrete toe/backing is M10 — the RCC stem must be M25+). If in doubt, use M20 — the cost difference from M10 to M20 is modest compared to the risk of under-strength structural concrete.
💧 Water — The Critical Variable in Nominal Mix
The biggest weakness of the nominal mix system is water control. The 1:3:6 ratio specifies proportions of dry materials only — it says nothing about water quantity. On site, water is typically added “to workability” — which usually means much more than needed, and the resulting w/c can be 0.80–1.20 — far above the designed relationship.
Excess water doesn’t make concrete stronger — it makes it weaker. Water beyond what cement needs for hydration (~w/c 0.23) evaporates and leaves pores. M10 concrete with w/c = 0.90 achieves 6–8 MPa; with w/c = 0.65 it achieves 12–15 MPa — while both use the same 1:3:6 material ratio.
Water Guidance for M10 1:3:6 on Site
For a 200-litre tilting drum mixer (1 bag cement per batch):
Target: approximately 28–32 litres per batch (w/c ≈ 0.56–0.64)
Practical test: Mix dry first. Add water slowly. Stop when slump is 75–100mm (good for blinding/levelling) or 25mm (for DLC). Once the concrete can be shaped and holds its form, stop adding water.
Use a measured bucket — never a free-flowing hose. Mark the bucket at 30 litres and keep it as the water measure for the mixing crew.
Water per batch for 1:3:6 (1 bag cement):
Batch cement = 50 kg (1 bag)
Target w/c = 0.60 (reasonable for M10 blinding)
Target water = 50 kg × 0.60 = 30 litres per batch
For different workability (slump):
DLC (15–25mm slump): 24–26 L per batch (w/c ≈ 0.48–0.52)
Blinding (75–100mm): 28–32 L per batch (w/c ≈ 0.56–0.64)
Levelling (>100mm): 32–36 L per batch (w/c ≈ 0.64–0.72)
Never exceed 40 L per batch (w/c 0.80):
→ Strength drops below 10 MPa
→ Excessive segregation and bleeding
❌ “Add water until it looks right”
The most common site instruction that undermines M10 quality. Concrete that “looks right” to the mixing crew is typically at w/c = 0.90–1.20 — achieving only 5–8 MPa, barely half of the M10 target. Use a measured bucket. Supervise water addition. For blinding, a slump of 75–100mm is sufficient and achievable at w/c ≈ 0.60.
❌ Common Mistakes with 1:3:6 Nominal Mix — and Fixes
❌ Using full gauge boxes of damp sand
Damp sand bulks — full gauge box of damp sand has only 70–80% of the intended dry sand mass. Actual ratio becomes ~1:2.25:6. Mix is harsh and lean.
✅ Fix: Reduce gauge box fill by bulking factor
If sand bulking = 25%, fill each farma only to 75% of its height. Monthly bulking test (IS 2386 Pt.3) — adjust fill level accordingly.
❌ Batching by mass using 1:3:6 as mass ratio
Sand (Sg 2.65) and stone (Sg 2.68) are much denser than cement (Sg 3.15). Using 1:3:6 by mass gives completely wrong proportions — far too lean in cement.
✅ Fix: Always use gauge box volume for nominal mix
1:3:6 is a volume ratio. Use gauge boxes of identical size. If weigh-batching is used, convert using IS 10262 absolute volume method (designed mix) — don’t weigh-batch nominal mix ratios.
❌ Using M10 for reinforced columns or beams
Any structural element with reinforcement requires minimum M20 per IS 456. Using M10 for RCC elements is a code violation regardless of actual achieved strength.
✅ Fix: Use M10 only for plain concrete works
Restrict M10 to blinding PCC, DLC sub-base, levelling courses, cyclopean fills, and plain non-structural elements. Step up to M20 nominal or M25+ designed for any reinforced element.
❌ No measurement of water — hose straight into drum
w/c reaches 0.90–1.20. Strength drops to 5–8 MPa. Blinding layer cracks under compaction of RCC above. Completely defeats the purpose of the PCC layer.
✅ Fix: Measure water with a marked bucket
Mark a bucket at 28–32 L. Use exactly that amount per batch. Supervisors must enforce this — especially in hot weather when the crew adds more water “to keep it workable.”
❌ Using 40mm stone for thin (50mm) blinding
40mm stone in a 50mm layer: stone particles cannot be properly embedded — they stick out above the layer surface. Aggregate that isn’t surrounded by paste provides no strength benefit.
✅ Fix: MSA ≤ 1/3 of layer thickness
For 50mm blinding: MSA ≤ 17mm → use 10mm or 12.5mm stone. For 75mm blinding: MSA ≤ 25mm → 20mm stone is fine. For thicker mass pours: 40mm stone saves cement.
⚖️ 1:3:6 Nominal vs IS 10262 Designed M10
For small pours (<10 m³): Use 1:3:6 nominal — designed mix cost and effort are not justified.
For large pours (>50 m³): Consider IS 10262 designed M10 — typically 15–25 kg/m³ less cement than nominal = ₹1,140–1,900 saving per 100 m³ at ₹380/bag. More than enough to cover the cost of a simple mix design.
When 1:3:6 Nominal Mix Is Right
- Small volumes (under ~10–15 m³)
- Remote sites where weigh-batch plant is unavailable
- Single-use temporary works (formwork protection, site road base)
- Any location where IS 10262 trial mix timeline (28+ days) is impractical
- Blinding below M20–M25 RCC where documentation requirements are minimal
When IS 10262 Designed M10 Is Better
- Large volumes (50 m³+) — cement savings are substantial
- Government / infrastructure projects requiring documented mix design
- RMC plant already in use — designed mix costs nothing extra to batch
- DLC sub-base specifications requiring documented 7-day strength verification
- Any project where QC records are required (IS 456 Cl.17.1)