# Design Procedures for Sustainable Structural Concretes Using Wastes and Industrial By-Products
## 2 Experimental Program  
### Materials  
In this research two reference structural concretes (REF1 and REF2) were selected as the conventional mixtures. These two mixtures have distinct formulations, since the REF2 mixture has a lower cement amount relative to the REF1 mixture. Additionally, REF1 has no FA powder. The reference structural concrete REF1 showed a slump class S3 and was classified as of strength class C30/C37. The solid skeleton of REF1 was composed of natural aggregates with grain size fractions of 6-14 mm and 14-20 mm medium sand (0-4 mm) and fine sand (0-2 mm). Portland cement CEM II/A-L 42.5 R (CEM) was used as binder, and a plasticizer (PL) based on modified lignocellulosic and a last generation superplasticizer (SP) based on poly aryl ether (PAE) polymers (Master Builders) were used. The water/powder (\(w/p\)) and water/cement (\(w/c\)) ratios were equal to 0.54 and 0.59 (in weight), respectively. REF 2 was composed of the same ingredients mentioned above for the REF1 mixture although fly ash (FA_2) was also included, obtained from Pego Thermoelectric Power Plant. It was also designed to achieve a slump class of S4 (\(\approx\)200 mm) and a strength class of C25/C30. The water/powder (\(w/p\)) and the water/cement (\(w/c\)) ratios were equal to 0.35 and 0.75 (in weight), respectively. During the project the FA was modified due to a supplier change, resulting in types of FA with two different densities. FA type 1 (FA_1) had a density of 2.42 Mg/m\({}^{3}\) and FA type 2 (FA_2) had a density of 2.35 Mg/m\({}^{3}\). FA_2 was the one employed in the reference mixture, REF2. The main physical properties and the quantities of the traditional mixtures' constituents are listed in Tables 1 and 2, respectively. In the particular case of the grain size fraction 6-14 mm and 14-20 mm, their physical properties were obtained for the larger fraction, namely the grain size fraction 6-20 mm. Subsequently, the characterized grain size fraction 6-20 mm was separated into two aggregates grain size fractions, 6-14 mm and 14-20 mm, for formulating the reference compositions. Figure 1a shows the particle size distribution of the natural aggregates. The sustainable concretes were mostly composed of EAFS, obtained from the production of steel in Porto (Portugal). In order to suppress the need for fine aggregates, natural sands with grain sizes of 0-2 mm and/or 0-4 mm were also used. FA_1 or FA_2, and limestone filler were used as fine materials, as well as plasticizer (PL) and superplasticizer (SP). Portland cement CEM II/A-L 42.5 R (CEM) was again used as the binder. The water/powder (\(w/p\)) and water/cement (\(w/c\)) ratios varied between 0.30-0.55 and 0.54-0.91 (in weight), respectively. EAFS was divided into seven different grain sizes of 0-0.5 mm, 0.5-4 mm, 0-4 mm, 4-10 mm, 10-14 mm, 14-20 mm and 0-20 mm. FA_2 was used in EAFS8C1, EAF8D1, and FRC_EAFS mixtures. The remaining EAFS mixtures were made using FA_1. The main physical properties of the ingredients EAFS and FA are listed in \begin{table}
\begin{tabular}{c c c c} \hline  & **REF1** & **REF2** \\ \hline CEM II/A-L 42.5 R & 280 & 205 \\ FA\_2 & & 115 \\ Sand 0-2 & 415 & 350 \\ Sand 0-4 & 495 & 530 \\ Aggregate 6–14 & 552 & 388 \\ Aggregate 14–20 & 430 & 580 \\ SP & 1.6 & 1.6 \\ PL & 1.4 & 1.6 \\ Water & 165 & 154.1 \\ \hline \(w/p\) & 0.54 & 0.35 \\ \(w/c\) & 0.59 & 0.75 \\ \% Aggregates & 87.11 & 81.48 \\ \% FA & — & 9.48 \\ \hline \end{tabular}
\end{table} 
Table 2: Reference mixture compositions, REF1 and REF2 [kg/m\({}^{3}\) or L/m\({}^{3}\)].