Ali Allahverdi - Department of Chemical Engineering, Iran University of Science and Technology, Narmak ۱۶۸۴۶, Tehran, Iran,
Shokoufeh Vakilinia - Department of Chemical Engineering, Iran University of Science and Technology, Narmak ۱۶۸۴۶, Tehran, Iran,
Pooneh Gharabeglu - R&D Department, NIOEC Company, No.۲۶۳, Ostad Nejatollahi st., Tehran, Iran

Spent catalyst from Residue Fluidized Catalytic Cracking unit of oil refining processes is one of the important waste materials that should be treated in a suitable way. The main goal of this research is to investigate the effects of RFCC spent catalyst on workability, setting times, and compressive strength of Portland cement paste. Results show that workability and setting times of fresh pastes decrease by increasing the percentage of cement substitution. A substitution of cement by spent catalyst between 15 to 20% by weight could increase the 28-day compressive strength of the paste up to 78 MPa which shows 42% increase compared to the plain system, i.e. 55 MPa. The interesting result is that it is possible to have high substitutions up to 40% without any reduction in the 28-day compressive strength compared to plain system. The RFCC spent catalyst is therefore a high quality complementary cementitious material.

Spent Catalyst, Residue Fluidized Catalytic Cracking, Portland Cement