*Article* **Evaluation of Cement Performance Using Industrial Byproducts Such as Nano MgO and Fly Ash from Greece**

**Panagiota P. Giannakopoulou 1, Aikaterini Rogkala 1, Paraskevi Lampropoulou 1, Maria Kalpogiannaki <sup>1</sup> and Petros Petrounias 1,2,\***


**Abstract:** The need for environmentally friendly construction materials is growing more and more these days. This paper investigates byproducts from Greece, such as magnesite tailings from Evoia and fly ash from Kardia (Ptolemais), in order to evaluate their suitability as cement additives. For this purpose, the raw materials were tested and studied regarding their mineralogical and chemical components for their morphological characteristics. Different cement specimens of various mixtures of raw materials were produced and tested. These raw materials are considered suitable for cement additives. The effect of nano MgO content seems to have played a more critical role in the physicomechanical performance of produced cement compared to that of the fly ash content. Furthermore, more satisfactory results in the physicomechanical properties of the produced cement gave samples of group II containing 3–4% of nano MgO. Nano MgO content up to 4% seems to have negative influence on the compressive strength of the produced cement, simultaneously reducing its durability. The increase of nano MgO content leads to the increase of the expansion of the produced cement specimens. In the early stage, the expansion rate was intensively larger. With the consumption of nano MgO, the expansion in the later stage gradually slowed down and tended to stabilize.

**Keywords:** magnesite tailings; nano MgO; fly ash; cement
