Reactivated cementitious materials from hydrated cement paste wastes

Hydrated cement pastes subjected to high temperature dehydration have been shown to develop a cementitious behavior upon rehydration that could enable recycling of hydrated cement wastes as alternative binders of high environmental value. In order to evaluate the potential of this recycling option it is first necessary to identify material and process factors affecting the performance of the reactivated cementitious materials produced. This paper presents the findings of a fractional factorial experiment designed to screen factors based on their effect on the strength developed by pastes incorporating materials reactivated from laboratory sourced hydrated cement pastes. Results allowed identification of factor and factor-interaction effects involving 7 of the 9 factors under study, which would be relevant in optimizing the recycling process. Highest strengths observed in the experimental region explored were 20, 32.8 and 39 MPa at 7, 28, and 90 days, respectively, for reactivated material pastes mixed at 0.7 W/CM ratio.