Frequently Asked Questions

What concrete temperature is the lower limit at which Conplast SD110 is effective and what other measures are needed?

Conplast SD110 is effective at accelerating cement hydration at concrete temperatures as low as approximately 2 degrees Celsius. Below zero degrees Celsius, the concrete will freeze regardless of the accelerating admixture, and frozen concrete cannot hydrate or gain strength. The admixture must therefore be used in conjunction with cold weather concrete protection measures — not as a standalone solution. These measures include: using warm mixing water (heated to approximately 40 to 60 degrees Celsius) to raise the concrete temperature at mixing; protecting the concrete from freezing after placement by covering with insulating blankets, tarpaulins, or temporary enclosures with heating; using the minimum water-cement ratio consistent with the workability requirement (lower w/c generates more heat of hydration); and protecting the concrete for the minimum period needed to achieve the frost-resistant strength (typically 3.5 MPa before exposure to freezing). Conplast SD110 reduces the time needed to achieve this protective strength in the thermally protected concrete, allowing the insulation and heating protection to be removed earlier and reducing the cost of cold weather concrete protection.

Is Conplast SD110 chloride-based and can it be used in reinforced concrete without risk of corrosion?

Conplast SD110 is a non-chloride set accelerator — it does not contain calcium chloride or other chloride compounds. This is a critical specification requirement for any set accelerating admixture used in reinforced concrete, because calcium chloride (the traditional set accelerating agent that was historically used before non-chloride alternatives were available) accelerates corrosion of the reinforcing steel even at the levels used for concrete acceleration. All Indian construction standards, including IS 9103 (specifications for concrete admixtures) and the relevant bridge and structural concrete specifications, prohibit the use of chloride-containing admixtures in reinforced concrete. Conplast SD110 as a non-chloride admixture is therefore safe for use in reinforced concrete, prestressed concrete, and any concrete with embedded metallic elements without risk of accelerated chloride-induced corrosion of the reinforcement.

Can Conplast SD110 be used in summer concrete to accelerate setting in high temperatures?

No. Conplast SD110 is a set accelerator formulated for cold weather conditions where the problem is that cement hydration is too slow. In summer concrete at ambient temperatures of 35 to 45 degrees Celsius (as is common across Delhi NCR and North India in May and June), the cement hydration rate is already fast — concrete sets quickly, and early strength gain is rapid. Adding a set accelerator to hot summer concrete would make the setting even faster, severely reducing the pot life (working time) and potentially causing flash set or uncontrollable early stiffening of the concrete. For hot weather concrete in Indian summer conditions, the appropriate admixture is a set retarder (such as Conplast R from the Fosroc range) that slows the cement hydration rate to maintain workability in hot conditions. The set accelerator and set retarder serve opposite functions and must not be confused or interchanged. Consult Space Arc Engineering for the appropriate Fosroc admixture for the specific ambient temperature and concrete performance requirements.