Effect of thermal and mechanochemical activated kaolin clay onthe mechanical properties and structure of the cement basedcomposites

Predmet ovog istraživanja je razvoj nove generacije mineralnih dodataka, dobijenih termičkom i mehanohemijskom aktivacijom kaolinske gline i ispitivanje svojstava kompozita, u kojima je deo portland cementa zamenjen dobijenim pucolanskim materijalima, metakaolinom i amorfnim kaolinom, za različite režime nege. Rezultati su pokazali da su termička i mehanohemijska aktivacija kaolinske gline jednako pogodne metode za dobijanje pucolanskih materijala. Pozitivni efekti na čvrstoće pri pritisku postižu se primenom do 30 % metakaolina u kompozitima pri normalnom režimu nege, a uz dodatno mlevenje, sadržaj metakaolina se može povećati do 40 %, uz dodatak CH. Amorfni kaolin se može primeniti u kompozitima, sa stepenom zamene portland cementa do 10 %, pri normalnom i autoklaviranom režimu nege.The subject of this research is development of a new generation of mineral admixtures, obtained by thermal and mechanochemical activation of kaolin clay, and testing of the properties of the cement based composites, where a part of the portland cement is replaced by pozzolanic materials, metakaolin and amorphous kaolin, for different curing conditions. The results showed that thermal and mechanochemical activation of kaolin clay were equally suitable for obtaining pozzolanic materials. Positive effects on the compressive strength could be achieved by using up to 30 % of MK, and with additional grinding after thermal activation, content of MK could be increased up to 40 %, with the addition of CH, under the normal curing conditions. Amorphous kaolin could be used in composites with a cement replacement level of 10 %, under the normal and autoclave curing conditions