The production of these blocks begins with the preparation of a base of silica sand and/or pulverized ash (PFA), lime, cement, gypsum / anhydrite, water and aluminum. Depending on the proportion of these components used, different types of concrete are obtained, each with different mechanical properties. Once the mixture is ready, the blocks undergo a material curing process in an autoclave.
The treatment process consists of:
1- Initial sweep: the steam valve and the aeration valve are opened simultaneously for a programmed time to apply an initial vacuum and expel part of the air inside the autoclave. This process allows to eliminate the pores in the surface of the concrete.
2- Heating and treatment: the steam is introduced in a controlled way inside the autoclave until reaching a temperature of over 190ºC and a steam pressure of 12 bar. Steam conditions are maintained for 6-12 hours to cure the aerated concrete.
3- Cooling: as it is steam treatment, depressurization and cooling are carried out in parallel by discharging the steam from inside the autoclave.