Concrete sleepers steam curing

[ione]

Is anyone aware of the typical duration of the steam curing cycle for concrete railway sleepers? The european standard in force prescribes the temperature gradient and the max temperature of the cycle, but no mention about its duration.

Thanks

 

[dicksewerrat]

Call the people that make them. Ask for the ASTM for the sleeper.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[concretemasonry]

ASTM would only be concerned with the age at testing and not the concrete production process. ASTM is concerned with materials, product standards and testing procedures.

If this is for a plant production, I would go to the manufacturer (most are European companies) of the equipment used to get some idea of the curing duration time. They know more about the manufacture of the products and relationships between the materials, the plant thermal characteristics (mass is important) and cycling times.

The European standards probably do not prescribe a curing duration because of the wide range of possibilities. The temperature gradient may be very slow, but 6 hours to 24 hours might be common depending on the materials and process. In a controlled plant environment, 8000 psi for a concrete block in less than 12 hours is possible and after that, the hydration and shrinkage is completed. Atmospheric curing will be somewhat slower and depending on the properties desired varied.

Specifying the limit of the maximum temperature does limit the processing cycles to certain methods.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[KateP]

For ione:

If You are not on the pressure with answer to Your question, please wait 2 weeks. In the midlle of May I'm going to precast factory in Europe where railway sleepers are produced... I will ask.

 

[Ron]

ione....curing is done until the appropriate properties are achieved, usually some percentage of the ultimate strength of the material. This is empirical, depending on the equipment, materials and processes employed.

 

[ione]

Thanks everybody for your replies.

KateP should you get useful info during your journey, please consider they'll be welcome.