## 2 Materials and Methods  
The subject of this research is the basic properties of concrete mixes and of hardened concrete with various additions. Two types of additions were used: siliceous fly ash (FA) and waste-glass powder (GP). The control mixes were produced with fly ash, which has been successfully used in concrete production for many years. From the observations made during quality control of works and materials used for the national roads in Poland, we knew that the content of fly ash in concretes can reach 50% by weight of cement (on the basis of the analysis of the specifications of C12/15 concrete used on national roads in the Polish province of West Pomerania). The amounts of fly ash added to the mix were 22.5% and 45% of the weight of cement (the percentage of cement remained unchanged). The design of the tested mixes was prepared on the basis of the control mix design, with  
Figure 1: View of waste glass; raw (**a**) and precleaned (**b**). fly ash being replaced by waste-glass powder. Therefore, a total of four series of concrete samples were prepared. The designations of the respective mixes indicate the type and the percentage content of the addition in relation to the weight of cement. The water to cement ratio (W/C) of 0.8 was constant in all the concrete mixes, and so was the grain size distribution. It was assumed that strength class C12/15 concrete, according to EN 206 [20], would be obtained after 28 days of curing. Concrete mixes were prepared using general-purpose CEM I 42,5R Portland cement and natural aggregate, which was obtained by mixing washed sand with gravels of 2/8 mm and 8/16 mm grading. The mix specifications are given in Table 1 below. The additions to concrete used in this research had different properties (Figure 2). Fly ash originated from coal combustion in the Dolna Oda power plant. Glass powder was obtained by crushing prebroken brown glass bottles in a laboratory crusher and grinding them in a Micro-Deval apparatus. The Blaine value of ground waste glass obtained in this way was 4737 cm\({}^{2}\)/g, and the Blaine value of fly ash was 3983 cm\({}^{2}\)/g. In this respect, fly ash is closer to cement (3728 cm\({}^{2}\)/g). The highest density was obtained from cement (3.10 g/cm\({}^{3}\)), and the lowest from fly ash (2.00 g/cm\({}^{3}\)). The density of waste-glass powder was 2.52 g/cm\({}^{3}\). Fly ash and ground glass differ in terms of chemical composition. Brown glass powder contains more SiO\({}_{2}\) (ca. 70%) [13; 16; 17] than fly ash (ca. 50%) on average [16; 21]. The consistency of the produced concrete mixes was evaluated using the slump cone test according to EN 12350-2 [22], their density was measured according to EN 12350-6 [23], and the total air content was determined with the pressure gauge method according to EN 12350-7 [24], ten minutes after mixing the components. Samples for compressive strength \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Component (Amount per 1 m\({}^{3}\) (kg))**} & \multicolumn{4}{c}{**Mix Symbol**} \\ \cline{2-5}  & **C\_FA\_22.5** & **C\_FA\_45.0** & **C\_GP\_22.5** & **C\_GP\_45.0** \\ \hline CEM I 42.5 R (Cemex) & 200 & 200 & 200 & 200 \\ Sand 0/2 (Bielinek) & 900 & 900 & 900 & 900 \\ Gravel 2/8 (Ognica) & 430 & 430 & 430 & 430 \\ Gravel 8/16 (Ognica) & 450 & 450 & 450 & 450 \\ Fly ash (Dolna Oda) & 45 & 90 & - & - \\ Waste-glass powder & - & - & 45 & 90 \\ Water & 160 & 160 & 160 & 160 \\ Water/cement ratio & 0.8 & 0.8 & 0.8 & 0.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Mix specifications (the sources of the materials are given in parentheses). Figure 2: Waste-glass powder (**a**) and fly ash (**b**) used for producing the tested mixes. testing according to EN 12390-3 [25] and for freeze-thaw durability testing according to PN-B-06250:1988 [26] were moulded in the next step. A compressive strength test was performed in compliance with EN 12390-3 [25]. Six 150 \(\times\) 150 \(\times\) 150 mm concrete cubes were made from each test series.