Moist heat treatment for concrete products - in tunnel kiln with preheating, humid heating, isothermal holding and cooling zones

摘要

A moist heat treatment of concrete and ferro-concrete articles takes place in a tunnel kiln where the articles are preheated by hot air of 40-100 deg.C and are treated in the next zone by a steam-air mixt. for 1-6 hrs. In the following zone, they are treated isothermally at 60-95 deg.C and 100% relative humidity for 2-6 hrs., and finally cooled with a coolant of 35-90% relative humidity for 0.3-1.5 hrs. This creates optimum conditions for the thermodynamic parameters. The results are a higher strength, a better frost resistance and a redn. of 30-40% of the treatment time.