Evaluation of Cement Performance Using Industrial Byproducts Such as Nano MgO and Fly Ash from Greece  
[PERSON]  
1 Section of Earth Materials, Department of Geology, University of Patras, 26504 Patras, Greece;  
[EMAIL_ADDRESS] (P.P.G. ); [EMAIL_ADDRESS] (A.R. );  
[EMAIL_ADDRESS] (P.L. ); [EMAIL_ADDRESS] (M.K.) [PERSON]  
1 Section of Earth Materials, Department of Geology, University of Patras, 26504 Patras, Greece;  
[EMAIL_ADDRESS] (P.P.G. ); [EMAIL_ADDRESS] (A.R. );  
[EMAIL_ADDRESS] (P.L. ); [EMAIL_ADDRESS] (M.K.) [PERSON]  
1 Section of Earth Materials, Department of Geology, University of Patras, 26504 Patras, Greece;  
[EMAIL_ADDRESS] (P.P.G. ); [EMAIL_ADDRESS] (A.R. );  
[EMAIL_ADDRESS] (P.L. ); [EMAIL_ADDRESS] (M.K.) [PERSON]  
1 Section of Earth Materials, Department of Geology, University of Patras, 26504 Patras, Greece;  
[EMAIL_ADDRESS] (P.P.G. ); [EMAIL_ADDRESS] (A.R. );  
[EMAIL_ADDRESS] (P.L. ); [EMAIL_ADDRESS] (M.K.) Footnote 1: email: {c.c.p.cat}  
Footnote 2: email: {[EMAIL_ADDRESS]}  
Footnote  
One of the effective ways to reduce cracking is by adding expansion agent in cement concrete or by using the expansion generated during the hydration process of expansion agent to compensate the shrinkage of cement concrete [5; 6]. Nowadays, the expansion agents mainly used in several applications primarily include sulfoaluminate-type, CaO-type, and MgO-type expansion agents. In comparison with the first two kinds of expansion agents, MgO expansion agent (nano MgO) displays a lot of advantages, including less water requirement for hydration, stable hydration product Mg(OH)\({}_{2}\), adjustable design of expansion process, and so on, in order to widely to be used in modern concrete [10]. Since the 1970s, numerous researchers have begun to study MgO expansion agent (MEA), which has been applied to a wide range of buildings, such as dams. The expansion produced by MEA hydration is used to compensate the temperature drop shrinkage and dry shrinkage of mass concrete, effectively improving the crack resistance and durability of the structure [11; 12]. Cements with high MgO content have gained more and more popularity in the last decade, perhaps due to the augmented concern about climate change, with the intention and need of reducing the CO\({}_{2}\) emissions regarding the production of conventional Portland cements. Some authors believe that it is possible to produce such type of cements with a high MgO content and reduced CO\({}_{2}\) emissions [13]. In recent decades, the major motivation for the development and uptake of MgO-based cements has been driven from an environmental standpoint. The lower temperatures required for the production of MgO compared to the conversion of CaCO\({}_{3}\) to PC and the energy savings associated with this reduced temperature have led researchers to envision MgO-based cements as being central to the future of ecofriendly cement production. Equally, the ability of MgO to absorb CO\({}_{2}\) from the atmosphere to form a range of carbonates and hydroxycarbonates lends itself well to the discussion of \"carbon-neutral\" cements, which could potentially absorb close to as much CO\({}_{2}\) during their service life as was emitted during their manufacture. These two interconnected aspects have led to a recent explosion in interest, both academic and commercial, in the area of MgO-based cements. Magnesium is the eighth most abundant element in the Earth's crust, at -2.3% by weight, present in a range of rock formations such as dolomite, magnesite, and silicate. Magnesium is also the third-most abundant element in solution in seawater, with concentrations of -1300 ppm [5]. The mineral magnesite comprises a widely used source of magnesium oxide (MgO), because magnesium is considered a critical element by the EU. However, alternative sources, such as several Mg-rich silicates, may become more relevant in the near future.