MC-Bauchemie MC-Crete 316
A chloride-free liquid set accelerator that speeds early strength gain and shortens demoulding cycles in reinforced and prestressed concrete, without the corrosion risk of chloride-based products.
What is it?
A chloride-free liquid set-accelerating admixture from MC-Bauchemie, built on formate/calcium-formate chemistry to speed cement hydration in reinforced and prestressed concrete.
Where is it used?
Precast yards and prestressing beds producing beams, columns, slabs, piles, manhole rings, pipes, kerb stones and paver blocks, plus cold-weather site pours where early strength matters.
Why use it?
It brings forward demoulding, freeing moulds and beds faster, while its nil-chloride formulation keeps it safe for steel reinforcement and tendons where chloride accelerators are barred by code.
How is it applied?
Dosed into the mix water at 1.0 to 2.5 percent by mass of cement before the water enters the mixer, never added neat onto dry cement or aggregate.
About MC-Bauchemie MC-Crete 316
MC-Crete 316 is MC-Bauchemie’s answer to a problem every precast and prestressing operation runs into: mould and bed turnover. In a yard, the mould is the bottleneck. The faster a casting reaches handling strength, the sooner the mould is stripped, cleaned and reused, and the more units a shift can produce from the same set of forms. MC-Crete 316 is a liquid accelerating admixture that pushes early hydration forward so that demoulding strength arrives in a fraction of the normal time, turning that bottleneck into throughput.
What sets it apart from older accelerators is what it leaves out. For decades the cheapest way to speed concrete was calcium chloride, but chloride ions attack the passive layer on embedded steel and drive reinforcement corrosion, which is why IS 456, EN 206 and AASHTO all prohibit chloride accelerators in reinforced and prestressed work. MC-Crete 316 delivers the acceleration through formate, calcium formate or calcium nitrate chemistry with nil chloride content, so it is safe in the exact structural and prestressed applications where the old chloride products were banned. It is compatible with OPC 43, OPC 53 and PPC, and works alongside MC-Bauchemie’s Centrament superplasticiser range in the same mix.
The technical insight
Concrete gains strength as cement hydrates, and the rate-limiting step in the early hours is the dissolution and reaction of the calcium silicate and aluminate phases. MC-Crete 316 works by feeding that reaction. The formate and nitrate salts raise the concentration of reactive ions in the pore solution, accelerating the nucleation and growth of calcium silicate hydrate so the mix stiffens and hardens sooner. In practice this means a casting can reach a demoulding strength of roughly 15 to 20 MPa in about 8 to 12 hours at 25 degrees Celsius, against 18 to 24 hours for the same mix without admixture. Crucially, the acceleration is a change in rate, not a penalty on the final result: the effect on 28-day compressive strength is neutral to marginally positive, so you gain early turnaround without trading away long-term performance. Because chloride is absent, none of this comes at the cost of the reinforcement, which is precisely why the chemistry matters for prestressed elements where a corroding tendon is a safety issue, not just a durability one.
Where it is used
- Precast beam and column production where fast mould stripping drives daily output
- Prestressed and pretensioned elements requiring early strength before transfer of prestress
- Precast slabs, piles and manhole rings cast in high-volume repetitive cycles
- Spun and cast concrete pipe manufacture
- Kerb stones, paver blocks and other small precast units
- Cold-weather concreting where low ambient temperature slows normal setting
- Repair and patch concrete that must be returned to service quickly
- Any reinforced concrete where a chloride-based accelerator is ruled out by code
Key advantages
- Nil chloride content, safe for reinforced and prestressed concrete under IS 456, EN 206 and AASHTO
- Cuts demoulding time to roughly 8 to 12 hours at 25 C, improving mould and bed turnover
- Reaches 15 to 20 MPa handling strength well ahead of an unaccelerated mix
- Neutral to marginally positive effect on 28-day strength, so no long-term penalty
- Dosage tunable from 1.0 to 2.5 percent to match temperature and demoulding targets
- Compatible with OPC 43, OPC 53 and PPC cements
- Works in combination with the Centrament superplasticiser range for workability plus acceleration
- Meets IS 9103 Type 6 and ASTM C494 Type C for accelerating admixtures
Limitations & considerations
- It accelerates set, so working and placing time is reduced, especially in warm conditions
- Overdosing beyond the recommended range can cause flash setting and does not proportionally improve results
- Acceleration slows as ambient temperature falls, so cold pours may need the upper dosage or supplementary curing
- It is a set accelerator, not a water reducer, so workability must be managed with a separate plasticiser
- As a liquid admixture it must be protected from freezing in storage and used within its shelf life
Selection & best practice
Always add MC-Crete 316 to the batch water before that water is introduced to the mixer, and never pour it neat onto dry cement or aggregate, where it cannot disperse evenly. Start dosage trials at the lower end of the 1.0 to 2.5 percent by mass of cement band and step up only if the target demoulding time is not met, using higher dosages for lower temperatures or tighter stripping schedules. Because the admixture shortens set, keep placing and finishing organised so concrete is compacted before it stiffens, and shorten the interval between batching and casting in hot weather. Run a plant trial on your specific cement, aggregates and any Centrament superplasticiser combination before locking in production dosages, and confirm the early and 28-day strengths on trial cubes rather than assuming a fixed conversion.
Specifications
| Product type | Chloride-free liquid set-accelerating admixture |
| Base chemistry | Formate / calcium formate / calcium nitrate |
| Appearance | Brown to amber liquid |
| Chloride content | Nil |
| Recommended dosage | 1.0 to 2.5% by mass of cement (1.0 to 2.5 litres per 100 kg cement) |
| Demoulding strength | ~15 to 20 MPa in 8 to 12 hours at 25 C |
| Effect on 28-day strength | Neutral to marginally positive |
| Standards | IS 9103 Type 6, ASTM C494 Type C, IS 1343 (prestressed) |
| Cement compatibility | OPC 43, OPC 53, PPC; Centrament superplasticisers |
Industry use cases
Precast concrete plants
Faster demoulding lets a fixed set of moulds produce more beams, columns and slabs per shift, directly lifting plant output.
Prestressed / PSC element manufacture
Early strength gain shortens the wait before prestress transfer while the nil-chloride formula keeps tendons corrosion-safe under IS 1343.
Concrete pipe and manhole units
Rapid stiffening suits spun and cast pipe, rings and covers cast in tight repetitive cycles.
Paver and kerb producers
Small repetitive units strip and stack sooner, easing yard congestion and speeding despatch.
Cold-weather site concreting
Counters the slow set of low-temperature pours so formwork can be struck and work can progress on schedule.
Frequently asked questions
Is MC-Crete 316 safe to use in reinforced and prestressed concrete?
How much faster can I demould with MC-Crete 316?
What dosage should I use?
Does accelerating the set reduce the final 28-day strength?
Can I use it together with a superplasticiser?
How is it added to the concrete?
How we position MC-Bauchemie MC-Crete 316
MC-Crete 316 sits in MC-Bauchemie’s admixture line alongside the Centrament superplasticiser range, which pairs with it when a mix needs both water reduction and acceleration rather than acceleration alone. Where a project team is already standardised on Fosroc, the equivalent chloride-free accelerator is Conplast NC, and for pure workability without acceleration our Fosroc water-reducing admixtures cover that need. Space Arc supplies and applies across all these brand families, so the choice comes down to the specifier’s approved-vendor list and the mix design rather than availability.
Fosroc Conplast NC — Choose Conplast NC when a project is standardised on Fosroc admixtures or the specification names Fosroc, as it is the equivalent chloride-free, formate-based accelerator for reinforced concrete.
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