Examination of the plasticizing process of compositions for siliceous foam-ceramic concrete technology
Application of the nonplasticized siliceous raw materials, such as bergmeals, opalous minerals and zeolites during the production of siliceous ceramics are currently of very limited use. Being used properly, the opalous minerals (flask etc.) allow to produce the wall ceramics with properties at least comparable with traditional articles of the same purpose. To obtain such ceramics, it is necessary to improve the strength of siliceous matrix significantly. The improvement can, in turn, be achieved by means of increasing the mutual clinkering rate of siliceous particles, which constitute the basis of the composition. As it was shown by A.S. Berezhnoj and K.K. Strelov, the duration of the clinkering necessary to produce the material with predetermined properties, depends strongly on the siliceous particles' size. For the production of ther effective foam-ceramic concretes the portland cement is used as a technological bond. Thus, the optimal liquid-solid relation have to be established. This relation can be controlled by means of addition of electrolytes and plasticizers. It is shown, that simultaneous addition of the «S3», «Melment», «F15» and «LST» plasticizers, together with soduim salt based liquifiers (NaF, Na <sub>3</sub>PO <sub>4</sub>, etc) leads to the mutual amplification of the plasticizing effect in case of mixtures (based on portland cement and opalous materials) for production of heat insulation FCC. The solid-liquid relation of multicomponent mixtures for heat insulating and general-purpose foam ceramic concretes can further be decreased by means of hyperplasticizers addition. This is due to both electrostatic and spherical effect. Among the all hyperplasticizers the ones with domination of later effect (caused by anion activity) are also more effective.