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ROOFPLAST SP 45
- Cold joints in large pours
- High strength concrete admixture
- Pumped concrete workability
- Ready-mix concrete admixture
ROOFPLAST SP 45 is a high range early strength super plasticiser and water reducing admixture based on modified sulphonated naphthalene polymers, compliant with IS 9103-99 (Amended 2003), BS-5075 Part 3 and ASTM-C-494 Type G. It reduces water-cement ratio by 20–30% without loss of slump, producing high density, cohesive concrete with reduced permeability and improved surface finish. Provides 4–5 hours of retardation to avoid cold joints in large concrete pours. Ideal for M-30 and above, high early strength, precast, ready-mix and pumped concrete. Non-toxic, non-flammable, chloride-free.
Specifications
Figures are controlled laboratory results. Actual site performance varies with substrate, temperature, humidity, application method and workmanship — please confirm the current product datasheet before specification.
Where to use ROOFPLAST SP 45: naphthalene based superplasticizer for large pours
ROOFPLAST SP 45 is a naphthalene based superplasticizer, a single component light brown liquid made from modified sulphonated naphthalene polymers. This high range water reducer cuts the water-cement ratio by 20–30% without loss of slump, giving dense, cohesive concrete with reduced permeability. It is added to the mix on its own and never premixed with other admixtures.
M-30 & High-Strength Concrete
Suited to M-30 and above, with 20–30% water reduction.
Precast Concrete
High early strength and improved surface finish for cast units.
Ready-Mix Concrete
Reduces water in the mix without loss of slump.
Prestressed & Mass Concrete
Chloride-free, with 4–5 hours of retardation for large sections.
Pumped Concrete
High workability and a cohesive mix for pumping.
Pavement & Highway Concrete
Dense concrete with reduced permeability for pavements and highways.
Bridges & Structural Concrete
For structural pours that need high workability without losing early strength.
No-Vibration Placement
High workability where the concrete is placed without vibration.
Dosage is 250–500 g per 50 kg bag of cement, adjusted for mix design and ambient temperature. It gives 4–5 hours of retardation, which is how to avoid cold joints in large pour work, and chloride content is nil. As a retarding superplasticizer it complies with IS 9103-99 (Amended 2003), BS-5075 Part 3 and ASTM-C-494 Type G. Store it above 5°C. Over-dosage causes very high workability and delays setting, so factor that into pour scheduling.
Armstrong Chemicals supplies ROOFPLAST SP 45 to sites across Telangana, Andhra Pradesh, Karnataka, Kerala and Tamil Nadu, including Hyderabad, Vijayawada, Bengaluru, Kochi and Chennai.
Same Materials. 20–30% Less Water. Higher Strength.
A naphthalene-based super plasticiser that reduces water-cement ratio by 20–30% without losing slump — with real M-30 trial data showing 76 N/mm² at 28 days versus 53 N/mm² for reference concrete. Three-standard compliance across IS, BS and ASTM.
Get a QuoteThe Slump-Strength Trade-Off in High-Grade Concrete
Achieving M-30 and above typically means more cement and a lower water-cement ratio — which reduces workability, makes pumping harder, and risks honeycombing and cold joints in large pours.
The ROOFPLAST SP 45 Advantage
20–30% water reduction without slump loss, 4–5 hours of retardation to avoid cold joints, and real site data showing 76 N/mm² at 28 days from the same 375 kg/m³ cement mix that produces 53 N/mm² without the admixture.
Real M-30 Trial Data — Not Just Claims
Actual mix design trial results: workable concrete at 0.5kg dosage achieved 138mm slump and 66 N/mm² at 28 days; strength-enhanced at W/C 0.45 achieved 154mm slump and 76 N/mm² — versus 52mm slump and 53 N/mm² for reference concrete without admixture.
4–5 Hours Retardation — Cold Joint Prevention
Built-in retardation of 4–5 hours enables large-volume monolithic pours in thin layers without cold joints — reducing shrinkage risk through lower heat of hydration and allowing uniform mixing and placement across extended pour cycles.
Three Standards. One Admixture.
Certified to the Indian standard for concrete admixtures.
Certified to the British Standard for superplasticising admixtures.
Certified to the American standard for water-reducing, high-range, retarding admixtures.
Real Site Data — M-30 Trial Results
Actual trial test results from an M-30 mix design — showing both the workability gain and strength gain from a real trial versus reference concrete without admixture.
| Mix | Dosage / 50kg | W/C | Slump | 3-Day | 7-Day | 28-Day |
|---|---|---|---|---|---|---|
| Reference (no admixture) | Nil | 0.55 | 52mm | 31 N/mm² | 44 N/mm² | 53 N/mm² |
| Workable Concrete | 0.5kg | 0.55 | 138mm | 32 N/mm² | 58 N/mm² | 66 N/mm² |
| Strength-Enhanced | 0.5kg | 0.45 | 154mm | 34 N/mm² | 62 N/mm² | 76 N/mm² |
Results obtained at 375 kg/m³ OPC cement, Zone II sand 40%, 20mm×5mm aggregate 60%.
Dosage Guidance
NSF + PCE incompatibility: do not combine ROOFPLAST SP 45 with PCE-based admixtures (e.g. ROOFPLAST PC 455) in the same mix without prior trial testing. Contact Armstrong technical support first.
- 1
Determine dosage: 250–500g of ROOFPLAST SP 45 per 50kg bag of cement
- 2
Adjust dosage based on mix design requirements, ambient temperature and project conditions
- 3
Add ROOFPLAST SP 45 separately to the mix — do not premix with other admixtures before dosing
- 4
Do not combine with PCE-based admixtures (such as ROOFPLAST PC 455) in the same mix without prior trial testing and technical support guidance
- 5
Over-dosage beyond the recommended range causes very high workability and retardation of setting time — factor into pour scheduling
- 6
For optimum dosage determination, conduct IS-specified mix design tests using job cement, aggregates and site water
- 7
Contact the ROOFPLAST SP 45 technical representative for specific application method guidance for your mix design
Built for High-Grade Concrete Performance
Proven by real trial data — 20–30% water reduction and higher strength from the same mix.
20–30% Water Reduction
Reduces water-cement ratio by 20–30% without loss of slump — producing dense, cohesive concrete with reduced permeability, improved surface finish and reduced porosity.
Three International Standards
IS 9103-99 (Amended 2003), BS-5075 Part 3 and ASTM-C-494 Type G — the broadest multi-standard compliance of any Armstrong admixture for concrete plasticisers.
4–5 Hour Retardation
Built-in 4–5 hour retardation reduces heat of hydration, prevents cold joints in large sections, and allows monolithic casting in thin layers without loss of original strength.
High Early Strength for Precast
Provides high early strength through controlled water-cement ratio — enabling earlier formwork stripping, faster production cycles and improved economics for precast and ready-mix operations.
Which plasticiser for your concrete grade
Armstrong admixture selection guide
Applicable Areas
Packing & Storage
Available in 1kg, 5kg, 20kg and 225kg packs. Shelf life of 1 year at 30°C warehouse conditions. ⚠️ Must be stored above 5°C — cold temperatures below this threshold affect product performance.
Admixture Compatibility
Add ROOFPLAST SP 45 separately to the mix — do not premix with other admixtures. ⚠️ Do not combine with PCE-based admixtures (e.g. ROOFPLAST PC 455) in the same mix without prior trial testing. NSF and PCE plasticisers interact and may affect slump retention and pumpability.
Compatible with Armstrong Admixtures
ROOFPLAST SP 45 is compatible with other Armstrong admixtures when each is added separately to the mix — not premixed together before dosing. Consult technical support for multi-admixture mix designs.
Product Brochure
Download Technical Datasheet
Full specifications, application systems, layering guides, and coverage tables.
Frequently Asked Questions
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