📅 IS 10262:2019 · IS 1199 · 2026
Workability Calculator
Slump selection by application, water adjustment for slump change, SP dosage for target slump, pumpability assessment, slump loss prediction and complete IS 10262 Table 2 water content reference
💧 Slump Selection by Application
📈 Water vs Slump Adjustment
⚙️ SP Dose for Target Slump
⏳ Slump Loss Predictor
🚯 Pumpability Assessment
💧Slump Selection by Application
IS 10262:2019 Cl. 5.4 — Recommended slump ranges for common concrete placement conditions
10–25 mm
Very Low / S1
Mass concrete · Roads & pavements (VeBe preferred) · Precast with strong vibration · Plain footings
25–75 mm
Low–Medium / S2
General RCC (columns, beams, walls) · Footings with light rebar · Slabs placed by crane · Normal-pour structural concrete
75–100 mm
Medium / S3
IS 10262 standard design slump · RMC general delivery · Bridge decks · Pumped concrete (min recommended) · Heavily reinforced sections
100–150 mm
High / S4
Pumped concrete (preferred) · Congested reinforcement · Tremie pours · Difficult placements · In-situ piles
150–200 mm
Very High / S5
Self-compacting approach (use with VMA) · Drilled shafts · Very congested sections · Pre-qualify with SCC testing if >175 mm
📋IS 10262 Table 2 — Water Content Reference
IS 10262:2019 Table 2 — Design water content (L/m³) for crushed aggregate by MSA and slump. Rounded aggregate: deduct 10 L/m³. M-Sand: add 5–12 L/m³.
| MSA Slump → | 25 mm | 50 mm | 75 mm | 100 mm | 125 mm | 150 mm |
|---|
IS 10262 Table 2 Adjustment Notes: Values above are for crushed granite/basalt aggregate. Rounded aggregate (river gravel): deduct 10 L/m³. M-Sand: add 5–12 L/m³ depending on stone dust content (higher stone dust → higher adjustment). Fly ash PPC: spherical FA particles may reduce water 5–8 L/m³ vs OPC with same aggregate. All values assume Zone II sand; Zone III/IV sand adds 6–18 L/m³ to required water.
📈Water Content Adjustment for Slump Change
Calculate how much water to add or remove to shift from a known slump to a target slump — with cement content recalculation to maintain w/c
✅ Water Adjustment Results
Slump Change—mm
Water Adjustment—L/m³
New Water Content—L/m³
New Cement Content—kg/m³
w/c Ratio—maintained
Strength Impact—vs original
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IS 10262 Cl. 5.4 — Water-Slump Relationship: For crushed aggregate concrete, each 25 mm increase in slump requires approximately +6 to +9 L/m³ additional water. To maintain the design w/c ratio, cement must also increase proportionally. The preferred approach for raising workability without extra water (and cement) is to increase superplasticiser dosage — this is the IS 10262 recommended method for achieving higher slump at M30+.
⚙️Superplasticiser Dose for Target Slump
Calculate the SP dosage required to achieve a target slump from a base slump without changing water content — maintaining design w/c ratio
Mix workability without any SP at design water content
✅ SP Dosage Results
Slump Increase Needed—mm
SP Dose (% cement)—% by mass
SP Volume per m³—L/m³
SP Volume per m³ (NSF)—L/m³ (if NSF)
Saturation Check—
Slump Retention—at 30°C
—
⚠️ Important: SP dosage for target slump must always be verified by a trial mix on your production cement. The saturation dosage — beyond which additional SP entrains air without further slump gain — varies by cement chemistry (C3A content, alkali level) and must be determined by the Marsh cone test or mini-slump test on paste. Never add more SP beyond saturation dosage in the field.
⏳Slump Loss Predictor
Estimate slump at delivery / placement based on mix design, SP type, temperature, and transit time
SCM slows hydration → better retention
Minimum slump needed at point of pour
⏳ Predicted Slump Profile Over Time
Usable Window—above required slump
Slump at 30 min—mm
Slump at 60 min—mm
Slump at 90 min—mm
Max Transit Time—minutes
SP Type Verdict—
Slump Loss Rule of Thumb (IS 4926 Guidance): At 30°C, expect 25–35 mm/30 min slump loss with NSF SP; 10–20 mm/30 min with PCE Type F; 5–12 mm/30 min with PCE Type G. Above 35°C, these rates approximately double. IS 4926 specifies that RMC concrete shall be discharged within 2 hours of water contact or 300 drum revolutions, whichever is first — and slump shall be within specification at the point of delivery.
🚯Pumpability Assessment
Check whether your concrete mix is suitable for pump delivery — IS 4926, ACI 304.2R and pump manufacturer guidelines
From sieve analysis; governs pump lubrication
🚯 Pumpability Assessment Results
MSA / Pipe Check—max 1/3 pipe dia
Slump Suitability—for pumping
Fines Content Check—lubrication adequacy
Equivalent Line Length—m (1m vert = 8m horiz)
Overall Verdict—
Recommended Slump—mm at pump
📌 Pumpability Key Rules (ACI 304.2R / IS 4926)
- MSA limit: Maximum aggregate size ≤ 1/3 of pump pipe internal diameter (20mm MSA → minimum 75mm pipe; 40mm MSA → minimum 125mm pipe)
- Slump at pump: Minimum 75 mm; optimal 100–150 mm. Below 75 mm → high pipe pressure → blockage risk
- Fines content: % passing 300 µm sieve × FA content should provide adequate paste for pipe lubrication. Cement + fines > 400 kg/m³ recommended for reliable pumping
- Equivalent line length: 1 m vertical rise = 8 m horizontal equivalent. Total equivalent length determines pump pressure requirement
- Slump tolerance: ±25 mm at delivery; if outside range, investigate moisture correction, do not add site water
📊Workability Test Methods — IS 1199 Reference
Conversion between workability measurement methods — Slump, VeBe, Compaction Factor, and Flow Table (IS 1199:2018)
📊 Workability Equivalents
Slump (mm)—IS 1199 Part 2
VeBe Time (sec)—IS 1199 Part 3
Compaction Factor—IS 1199 Part 4
Flow Table (%)—IS 1199 Part 5
Workability Class—
Recommended Use—
| Workability | Slump (mm) | VeBe (sec) | Compaction Factor | Flow Table (%) | IS Classification | Typical Use |
|---|---|---|---|---|---|---|
| Very Low | 0–25 | >12 | 0.75–0.80 | <340 | S1 | Mass concrete; roads; precast (ext. vibration) |
| Low | 25–75 | 6–12 | 0.80–0.85 | 340–380 | S2 | Lightly reinforced sections; footings; plain concrete |
| Medium | 75–100 | 3–6 | 0.85–0.92 | 380–410 | S3 | Normal reinforced concrete; IS 10262 design slump |
| High | 100–150 | 1–3 | 0.92–0.95 | 410–450 | S4 | Heavily reinforced; pumped concrete |
| Very High | >150 | <1 | >0.95 | >450 | S5 | Tremie; drilled shafts; SCC approach |