PRODUCT DESCRIPTION AND USE
BenzoRetarder is a set retarding chemical admixture specially designed for use in situations
where setting time of fresh concrete should be intentionally extended for a long time.
BenzoRetarder is recommended for use in the applications and purposes below:
Any type of concreting operation requiring extended setting time of fresh concrete.
Continuous and large volume concreting operations.
Mass concrete applications.
Concreting operations that cold joint formation is undesirable.
In case of fresh concrete transportation to very long distances.
Concreting works requiring extended time for placing, vibrating and surface finishing operations.
Concreting operations requiring re-vibration.
Operations in hot weather conditions.
ADVANTAGES AND PROPERTIES
BenzoRetarder significantly extends the initial and final setting time of cement. It is suitable
for use in all concreting operations where the fresh concrete must be remained in plastic
stage for long time.
Provides easiness in large-volume and continuous concreting operations requiring advanced
planning in production, transportation, pumping, placing, vibrating and surface
finishing of fresh concrete.
Reduces cold-joint formation risk in layered mass concrete production.
Provides advantage in continuous mass concrete production by keeping the first layer concrete
still capable of deforming as the upper layers successively placed in a long time.
Tabakalı kütle betonu uygulamalarında en alttaki tabakaların prizini tüm döküm tamamlanana
kadar uzatarak üst tabakaların ağırlığı ile hasar görmesini önler.
Does not affect the ultimate strength of retarded concrete
Prizi kontrollü olarak yüksek oranda geciktirmesine karşın nihai dayanımı olumsuz etkilemez.
Does not contain chloride or any other substances that may cause corrosion.
APLICATION DETAILS, SAUGGESTIONS AND WARNING
BenzoRetarder should be used by adding to the mixing water. Alternatively, it can be mixed
with 1/3 of mixing water and added to the fresh concrete produced with 2/3 of mixing water.
In case of addition to fresh mixture as described, additional mixing time of at least 3 minutes
at high speed should be applied. BenzoRetarder is not added to the dry mixture.
BenzoRetarder can be used together with superplasticizers without set accelerator effect.
In case of the combined usage with superplasticizers (without set accelerating effect), the
different types of chemical admixtures should not be mixed together and be used separately.
First the fresh concrete mixture should be prepared by the superplasticizer and then BenzoRetarder
should be added to the fresh mixture. Please contact R&D department of BENZEN
for further information.
BenzoRetarder can be used with Portland cement types described in TS EN 197-1. In addition,
it can be used in concrete mixtures containing mineral admixtures such as silica fume,
fly ash and ground granulated blast furnace slag. However, the required dosage for the best
performance should be determined on trial batches.
As BenzoRetarder significantly extends the initial and final setting time of cement, the plastic
stage of concrete will be maintained for a long time. Therefore, it should be considered
that the hydrostatic pressure will be remined on the surface of molds for a long time.
It should be noted that the retarded concrete may be more vulnerable to surface defects due
to evaporation. Evaporation from the surface of retarded concrete should be reduced or prevented
by covering the surface of fresh concrete with wet fabric.
BenzoRetarder should not be used together with set accelerators, hardening accelerators
and antifreeze agents.
BenzoRetarder should not be used in cold weather conditions.
Recommended Dosage:
The dosage of BenzoRetarder is a function of the ambient temperature during concreting and
the desired delay time of setting. In addition, the dosage is affected from the type of cement and
mixture properties of concrete. The recommended dosage rate is between 0.2% - 2% of weight
of binding material of concrete. Depending on the ambient temperature, retarding performance
of BenzoRetarder increases as the dosage increases. The usage of 1% BenzoRaterder (CEM 42.5
R, 300 kg/m3) extends the setting time around 19 hours, 13 hours and 5 hours at the ambient
temperatures of 15 °C, 25 °C and 35 °C, respectively. Similarly, 0.2%, 1.0% and 2.0 % usage of
BenzoRetarder at 20 °C ambient temperature result in 3 hours, 14 hours and 27 hours delay in
setting time, respectively. Therefore it is recommended that the appropriate dosage of BenzoRetarder
should be determined on laboratories which capable of simulating the expected ambient
temperature conditions of site or trial batches prepared on site directly.
The concretes containing overdose BenzoRetard may never set. Precence of mineral admixtures
such as silica fume, fly ash and ground granulated blast furnace slag may affect the optimum dosage
of BenzoRetarder for a target performance. The optimum dosage should be determined on
trial batches. Please contact R&D department of BENZEN for technical support.
