|Deys Betontechniek Nederland BV
Gelreweg 5, 3843 AN Harderwijk
Postbus 330, 3840 AH Harderwijk
Telephone +31 (0)341 41 51 48
(24 hr / day)
Fax (0341) 42 54 90
APPLICATION OF BETEC MORTARS AT LOW TEMPERATURES
The application range of cement based products is usually +5°C. Many BETEC products, however, can be ap-plied below this temperature. The water/cement factor of BETEC mortars fluctuates around 0.30. This value is extremely low in comparison with various other mortar brands. This value implies that the water content in BETEC mortar is only used for the chemical reaction with cement, i.e. relatively little water, which could lead to freezing, is left in the capillary pores. BETEC’s high fluidity is achieved with the use of high quality plasticizers and liquefiers, contrary to other materials in which a higher water/cement factor is used, which affects the fluidity. Because of the excessive use of this transport water these materials are much more likely to result in freezing of the sub-mould, because water expands when it freezes.
BETEC mortars than can be used in temperatures below +5°C:
Processing of BETEC mortars at temperatures below +5°C (DIN 1045):
Because of the delay in the hydration (hardening) process during low temperatures or frost the concrete needs to be protected from heat loss, freezing and dehydration.
In principle the above-mentioned BETEC mortars can be processed down to -5°C. However, a number of (win-ter) measures need to be imposed .
Required temperature of prepared mortar during processing:
In general it would seem that when the material has reached a tensile strength of 5 N/mm2, it will be resistant to frost and further drops in temperature will not inflict any damage.
It is advisable to store the material in heated conditions so that the water needs less heating.
Tabel 1: Mixture temperature to achieve a specific fresh mortar temperature.
PREPARATION WATER TEMPERATURE
^ = Temperature dry mortar ^ =Temperature fresh mortar
With hardening temperatures between -5 and +5ºC, the Betec 800 series (801, 804, 808, 816) will reach a strength of approx. 20-25 N/mm² after 24 hours, which ensures a continu-ous flow of operations.
This information sheet covers the use of moulding mortars; however, some other Betec mortars can be used in accordance with the above mentioned measures down to -5°C, i.e.: Betec 311, Betec 330,Betec 322, Betec 308, Betec 313, Betec 343 and Betec 383, Betec 860., Betec 200.