*Proceeding Paper* **Influence of Spent Fluid Catalytic Cracking Catalyst on the Properties of the New Binder Based on Fly Ash and Portland Cement †**

**Jelena Raki´c and Zvezdana Bašˇcarevi´c \***

Institute for Multidisciplinary Research, Belgrade University, Kneza Višeslava 1, 11000 Belgrade, Serbia **\*** Correspondence: zvezdana@imsi.bg.ac.rs

† Presented at the 10th MATBUD'2023 Scientific-Technical Conference "Building Materials Engineering and Innovative Sustainable Materials", Cracow, Poland, 19–21 April 2023.

**Abstract:** One of the measures to reduce the carbon footprint of the Portland cement (PC) manufacturing process is through a wider use of supplementary cementitious and waste materials. The main objective of this work was to produce a new binder using two different waste materials: fly ash (FA) from thermal power plants and spent fluid catalytic cracking catalyst (sFCCC) from petrol refineries. In order to improve their reactivity, both FA and sFCCC were mechanically activated prior to the preparation of the binder. The new binder consisted mostly of the waste materials (70 mass %), with PC as a minor component (30 mass %). It was found that using sFCCC as the binder component accelerated cement hydration and the pozzolanic reaction. The new binder had a shorter setting time and a higher early strength than the binder prepared without sFCCC.

**Keywords:** spent catalyst; fly ash; catalytic cracking; Portland cement; pozzolanic reaction
