THE CONCRETE MIX DESIGN LAB
A scientific concrete mix design calculator. Explore the materials, follow the method, prepare your trial.
YOUR MIX, EXPLAINED
01 / COMPOSITION
Absolute volume uses specific gravity. It is not loose bucket volume. ¹ Water carried by an admixture stays within its product share.
02 / STRENGTH RELATIONSHIP
Approximate Figure 1 readings · 28-day cube strength
The curves are an approximate redraw of IS 10262:2019 Figure 1, not measured results for your mix. SCM blends need material-specific trials.
Total binder : fine aggregate : coarse aggregate.
This proportion belongs to these inputs; it is not a universal M30 recipe.
DESIGN WITH THE CURVE
Drag the target points. Explore a sand–stone blend. See the batch change.
2.3 percentage points RMS difference from your target
One blend share must work across every sieve; some target shapes cannot be matched exactly.
LIVE BATCH PREVIEW
| Quantity | Current mix | Proposed | Change |
|---|---|---|---|
| Sand · as batched | 684.6 | 684.6 | — |
| Stone · as batched | 1236.9 | 1236.9 | — |
| Water to add | 157.7 | 157.7 | — |
| Total binder | 375.5 | 375.5 | — |
Binder and free-water target stay fixed. Aggregate volumes and wet batching quantities are recalculated using your SSD specific gravities, absorption and moisture.
Cumulative percent passing by oven-dry mass. Editing source values marks them as user-entered; no laboratory verification is implied.
| Sieve mm | Sand % | Stone % | Target % | Blend % |
|---|---|---|---|---|
| 0.075 | 0.5 | |||
| 0.15 | 2.0 | |||
| 0.3 | 5.6 | |||
| 0.6 | 14.7 | |||
| 1.18 | 23.4 | |||
| 2.36 | 30.8 | |||
| 4.75 | 37.7 | |||
| 10 | 56.2 | |||
| 20 | 97.4 | |||
| 40 | 100.0 |
For each sieve, blend passing = x × sand passing + (1 − x) × stone passing, where x is the sand fraction of oven-dry aggregate mass. Fit target finds the least-squares fraction across all displayed sieves, limited to 1–99% sand in this application.
For volume accounting, each dry share is multiplied by (1 + absorption) and divided by its bulk SSD specific gravity. The resulting volume fractions allocate the available aggregate volume. The fitted share replaces the IS table split and its optional coarse reduction.
The editable target and example curves are exploratory. This is not an IS 383 grading-envelope check, packing-density optimization or strength prediction. Constituent suitability, water demand, workability and physical trials still need evaluation.
Reference: combining aggregate gradations, Iowa DOT IM 531Absolute-volume closure: 1.000000 m³. Durability minimum: 300 kg/m³; maximum ratio: 0.50. These are selected checks, not a compliance certificate.
Admixture water contribution is set to 0%. Enter the supplier’s measured water fraction when applicable; do not assume a liquid product is water-free.
Strength reference readings, admixture reduction and material properties require trial verification. Sulphate exposure, chloride limits, constituent conformity and project-specific requirements need separate checks.
IS 10262:2019 ordinary/standard grade workflow · Selected IS 456:2000 durability provisions · Physical trials and project review required.
Engine 1.1.0; 1 m³; Moderate exposure; reinforced concrete. Preliminary trial only.
Cement: 375.543 kg
Fine aggregate (as batched): 684.646 kg
Coarse aggregate (as batched): 1,236.877 kg
Water to add at mixer: 157.728 kg
Chemical admixture: 3.755 kg
f′ck = max(fck + 1.65S, fck + X)
max(30 + 1.65 × 5.00, 30 + 6.50) = 38.25 MPa
Assumed standard deviation 5.00 MPa. The larger margin governs; characteristic and target strengths are different. (IS 10262:2019 · 4.2, Tables 1–2)
r = min(strength-based ratio, durability limit)
min(0.42, 0.50) = 0.42
The ratio is interpolated from approximate Figure 1 readings and rounded down to 0.01. It is a preliminary selection, not a measured strength prediction. (IS 10262 · 5.1 / IS 456 · Table 5)
W = (W₀ − shape adjustment) × slump factor × (1 − reduction)
(186 − 0) × 1.060 × 0.80 = 157.7 kg/m³
The starting water estimate is for SSD aggregates. The 3% change per 25 mm slump and admixture reduction are preliminary; actual workability must be measured. (IS 10262 · 5.3, Table 4)
B = max((W ÷ r) × trial increase, durability minimum)
max((157.73 ÷ 0.42) × 1.00, 300.00) = 375.5 kg/m³
Final w/b is 0.420 after minimum-content or trial adjustments. Replacement percentages are fractions of total binder mass. (IS 10262 · 5.4 / IS 456 · Tables 5–6)
Vagg = 1 − Vair − Σ [mᵢ ÷ (Gᵢ × 1000)]
1 − 0.0100 − 0.2802 = 0.7098 m³
Use specific gravity, not loose bulk density. Water carried inside the chemical admixture is counted once, within that product’s volume. (IS 10262 · 5.2, 5.7)
pCA = [p₀ + 0.2(0.50 − w/b)] × (1 − reduction)
[0.62 + 0.2 × (0.50 − 0.420)] × 1.00 = 63.6% coarse / 36.4% fine
SSD masses: fine 684.6 kg and coarse 1236.9 kg per m³. The optional reduction is a trial adjustment up to 10%, not an automatic pumpability guarantee. (IS 10262 · 5.5, Table 5)
mOD = mSSD/(1+A); Wsurface = mOD(MC−A)
Sand: 677.9 × (1−1)/100; stone: 1230.7 × (0.5−0.5)/100 = 157.7 kg/m³ mixer water
Total moisture and absorption use an oven-dry mass basis. Surface water 0.0 kg plus admixture water 0.0 kg is deducted from the free-water budget. (SSD mass balance · IS 10262 Annexes A–B)
Batch quantity = quantity per m³ × batch volume
Each constituent × 1.000 m³ = 1.000 m³ trial batch
Measure workability, fresh density, yield and strength; inspect segregation and bleeding. Revise the mix and record trials before project approval. (IS 10262 · 5.8)
Admixture water contribution is set to 0%. Enter the supplier’s measured water fraction when applicable; do not assume a liquid product is water-free.
Verify applicable code editions, material tests and project requirements. Reference graph is approximate, not measured mix performance.
UNDERSTAND THE METHOD
A concrete grade describes characteristic strength. It does not define a fixed ingredient recipe. Mix design brings strength, workability and durability together using the materials actually available.
Specify grade, exposure and workability. Test constituent specific gravities, aggregate grading, absorption and moisture.
Choose a trial ratio from material evidence, check durability, estimate workability water and calculate the binder demand.
Subtract paste and air from one cubic metre. Allocate the remainder to aggregates and correct the batch for moisture.
Measure slump, density and strength. Inspect bleeding and segregation, adjust the design and repeat with the actual materials.
VOLUME ≠ MASS
Specific gravity connects mass to absolute volume. At a specific gravity of 3.15, 31.5 kg of cement occupies 10 litres of absolute solid volume. Loose powder also contains spaces between particles, so its bucket volume is different.
Method reference: IS 10262, clause 5.7Equal absolute volume: 10 L each · illustrative specific gravities
MATERIAL SCIENCE
Small differences in the raw materials can change water demand, packing, workability and the measured strength.
The aggregate skeleton controls how much paste is needed between particles. Grading zones, shape and surface texture inform a starting mix; a trial confirms its workability.
Supplementary materials change binder chemistry and particle packing. Their contribution depends on source, dosage and curing. A replacement percentage alone cannot establish strength or durability.
Dosage and water reduction are separate inputs. Use supplier information and compatibility trials, and include water carried by liquid products in the water balance.
THE FINAL STEP IS PHYSICAL
Keep specimen shape, test age, curing and test method consistent when comparing results. Indian M grades use characteristic cube strength; cylinder strengths and international class labels are not interchangeable.
Photo shows general laboratory cylinder testing, not an M-grade cube test. Xb-70 / Simpson Gumpertz & Heger, Inc. · Public domain.
THE STANDARDS BEHIND THE PROCESS
This calculator implements the ordinary/standard grade IS workflow. Other regions are explained below as references; they are not interchangeable calculation modes.
Concrete mix proportioning. Target strength, water, binder, air, aggregate allocation and trial procedure.
Read source text Third-party copy reviewed; © BIS. Verify the applicable edition and amendments through BIS.Selected exposure-based limits for water/cement ratio, minimum content and grade. Project requirements may be stricter.
View referenced provisionsIS 383: aggregates; IS 2386 Part 3: specific gravity and absorption; IS 9103: admixtures. Relevant parts of IS 1199 and IS 516 govern fresh and hardened testing.
Find applicable BIS standardsMixture-proportioning guidance using absolute volumes. ACI structural requirements and applicable ASTM test methods have distinct roles.
ACI guideConcrete specification, performance, production and conformity, with national provisions. Verify the locally adopted edition, including the 2026 EN 206 revisions.
BSI referenceMaterials, construction and testing requirements. Exposure classes and test conventions need their own implementation.
CSA GroupConcrete specification and supply, and concrete test methods. These references do not convert an Indian trial into an Australian-compliant mix.
Standards AustraliaSpecial mixes—self-compacting, mass, fibre-reinforced, lightweight and M65+ high-strength concrete—need additional methods and tests. The present calculator does not certify those designs.
A FEW IMPORTANT DISTINCTIONS
The grade describes characteristic strength. Mix proportioning uses a higher mean target to allow for variation. The IS 10262 method checks both the statistical margin and the grade-based minimum margin.
No universal ingredient proportion establishes these grades. Strength, exposure, workability and actual material properties determine a trial mix. The calculated ratio shown here changes with your inputs.
A lower ratio can support higher strength for a given material system, but the concrete must still be workable, placed, compacted and cured properly. A graph cannot account for every production condition.
The SSD design includes water absorbed inside aggregates. Actual stockpiles may be wetter or drier. Correcting both aggregate mass and added water preserves the intended solids and free-water balance.
No. It is a transparent preliminary proportioning and learning tool. The selected code provisions do not replace material conformity checks, physical trials, acceptance testing or project-specific professional approval.