# Design Procedures for Sustainable Structural Concretes Using Wastes and Industrial By-Products
## 2 Experimental Program
### Materials
\begin{table}
\begin{tabular}{c c c c} \hline  & **Apparent Particle** & **Particle Density on an** & **Particle Density on a** & **Water Absorption,** \\
**Component** & **Density, \(\rho_{a}\)** & **Oven-Dried Basis, \(\rho_{nd}\)** & **Saturated-Dried Basis, \(\rho_{ssd}\)** & **WA\({}_{24}\)** \\  & **(Mg/m\({}^{3}\))** & **(Mg/m\({}^{3}\))** & **(Mg/m\({}^{3}\))** & **(\%)** \\ \hline SP & — & 1.18 & — & — \\ PL & — & 1.18 & — & — \\ CEM & — & 3.11 & — & — \\ Filler & — & 2.70 & — & — \\ FA\_1 & — & 2.42 & — & — \\ FA\_2 & — & 2.35 & — & — \\ Sand 0–2 & 2.64 & 2.62 & 2.63 & 0.2 \\ Sand 0–4 & 2.65 & 2.61 & 2.63 & 0.6 \\ Aggregate 6–20 & 2.70 & 2.64 & 2.66 & 0.8 \\ EAFS 0–4 & 3.58 & 3.49 & 3.51 & 0.7 \\ EAFS 4–10 & 3.47 & 3.25 & 3.31 & 2.0 \\ EAFS 10–14 & 3.40 & 3.22 & 3.27 & 1.6 \\ EAFS 14–20 & 3.34 & 3.18 & 3.22 & 1.6 \\ EAFS 0–20 & 3.42 & 3.25 & 3.29 & 1.6 \\ \hline \end{tabular}
\end{table} 
Table 1: Specific density of the natural and waste materials used in the concrete formulations. Table 1. The physical properties of EAFS grain size fractions 0-0.5 mm, 0.5-4 mm and 0-4 mm were obtained for the larger fraction, namely the grain size fraction 0-4 mm. The characterized grain size fraction 0-4 mm was then separated into the three EAFS grain size fractions for formulating the EAFS concrete compositions. Table 3 shows the estimated elements composition of the EAFS using XRF analysis and the estimated elements composition of FA_1 using XRF, SEM-EDS and XRD analysis. Figure 1b shows the EAFS aggregates particle size distributions with different fractions and Figure 2b shows the appearance of EAFS aggregates with a dimension between 0-20 mm, before its division into fractions. RTSF were provided by the tire production industry in Sines (Portugal) and were added to the EAFS concrete without any initial treatment or preparation. Typically, wastes from tire recycling are subjected to previous screening and cleaning in order to reduce the content of materials other than the steel fibers, for example rubber. However, in this research the viability of using the waste material directly was tested, in order to reduce energy and costs involved in the process. Figure 2a shows the RTSF, where it was possible to identify remains of tire rubber, synthetic fibers and steel fibers of different shapes, lengths and diameters. Table 4 shows the geometric properties of steel fibers. RTSF waste materials containing the steel fibers showed a specific density of 3.42 Mg/m\({}^{3}\). Figure 1: Particle size distribution of the used aggregates: (**a**) natural aggregates; (**b**) EAFS aggregates. Figure 2: (**a**) representative samples of RTSF; (**b**) EAFS aggregates (0–20 mm) before division into fractions. Mix Design of EAFS Structural Concrete  
In order to optimize the industrial process of producing EAFS concrete compositions while taking advantage of the least number of fractions, the design procedure was developed using the modified Andreasen and Andersen particle packing method, which reads as follows [32; 33]:  
\[P(D)=\frac{D^{q}-D_{min}^{q}}{D_{max}^{q}-D_{min}^{q}} \tag{1}\]  
where \(D\) is the particle size (\(\upmu\)m), \(P(D)\) is the fraction of the total solids smaller than size \(D\), \(D_{max}\) is the maximum particle size (\(\upmu\)m), \(D_{min}\) is the minimum particle size (\(\upmu\)m), and \(q\) is the distribution modulus. The distribution modulus is used to define the ratio between the fine and coarse particles in the mixture, which according to [PERSON]. [34] can vary between the values of 0.1 for fluid concretes and 0.9 for dense concretes. Studies suggest a \(q\) value in the range of 0.35-0.4 for EMC (Earth-Moist Concrete) [34], and of 0.23 for UHPC (Ultra-High Performance Concrete), UHPRRC (Ultra-High Performance Fiber Reinforced Concrete) and UHPHFRC (Ultra-High Performance Hybrid Fiber Reinforced Concrete) [35; 36; 37; 38; 39]. For