Set Retarders

Delays the set time of concrete.  Rarely used in zero-slump products (pavers, block, SRW’s) but common in ready mix concrete placed during hot weather.  Extends the period of workability to make placement and finishing possible.




ConTec SR-550


ConTec SR-550 is a ready-to-use liquid admixture used to retard setting times by controlling the hydration of cement in the manufacture of concrete products. SR-550 is compatible with a wide range of concrete admixtures , but should always be dispensed separately. SR-550 improves the properties of precast concrete when used in conjunction with air entrainment, such as AE-80 or AE-407.


ConTec SR-550 may be used wherever the need to retard the initial and final set times of concrete is applicable. SR-550 meets ASTM C 494/c 494M standards for Type B retardation and Type D water reducing admixtures. SR-550 improves uniformity and predictability in high performance concrete.


ConTec SR-550 is available in bulk quantities or packaged in 55 gallon (208 L) drums weighing 495 lbs (224 kg) and 265 gallon (1003 L) totes weighing 2385 lbs (1082 kg).


Specific Gravity at 77F…….…… ….. 1.21 – 1.24
Viscosity at 77F, cps ………… …..…. 100 max
Weight per gallon …………………. ….10.1 – 10.3
% Volatile matter (NVM(1)) ………… …… ~ 80
Appearance …………….. Dark Amber Liquid


● Improves workability and plasticity.
● Retards setting times in cementitious products
● Increases compressive strengths and reduces permeability.
● Affords a water reduction of 5% or better.
● Reduces segregation.


ConTec SR-550 can be stored over a wide range of temperatures but should not be allowed to freeze. Should SR-550 freeze, allow complete thawing before mixing by mechanical means. SR-550 has a minimum shelf like of 12 months. With proper storage conditions the shelf life can be greatly extended.


The addition rates for SR-550 will vary depending on the variations in job conditions and the concrete components being utilized. Typical dosage will range from 2 to 8 fl oz per 100 lbs of cement. Never mix other admixtures wit SR-550 before addition to mixer. Consult your ICT representative for assistance to determine the proper dosage for your application.