# Prediction of Self-Healing of Engineered Cementitious Composite Using Machine Learning Approaches
## 2 Experimental Program  
### Materials and Mixture Proportion  
In the experimental part, samples of ECC with different mineral admixtures were prepared. The materials including general-purpose cement (GPC), fly ash (FA), silica fume (SF), hydrated lime powder (LP), fine sand, polyvinyl alcohol (PVA) fibers, as well as water and high-range water-reducing admixture (HRWR) were used. The HRWR complies with AS1478.1-2000 and was added at the recommended dosages to achieve 80 \(\pm\) 20 mm slump (medium degree of workability). GPC and FA were supplied by Boral in accordance with Australian Standard AS 3972-2010 [43], while LP was the Adelaide Brighton Hydrated Lime with a specific gravity of 2.2-2.3 and a typical fineness of 0.1% retained on a 75 \(\upmu\)m sieve and less than 0.05% on a 250 \(\upmu\)m sieve. The physical and chemical properties of the cementitious materials are shown in Table 1. Fine sand with an average grain size of 150 \(\upmu\)m and a fineness modulus of 2.01 was used. Figure 2 shows the particle distribution of the fine sand. The PVA fibers were supplied by Domocrete, and their mechanical and geometrical properties are described in Table 2.  
All ECC mixtures were prepared with a constant water-to-cementitious-material (W/CM) ratio of 0.29 and a constant sand to CM (PC + FA + LP+SF) ratio of 0.36. All fine aggregates were in saturated surface- dried condition prior to mixing. The abbreviations for labeling specimens were adopted in such a way that the letters FA, SF, and LP stand for samples with fly ash, silica fume, and limestone as the binder materials, respectively. The number after the letters shows the percentage of materials in the binder system. For example, the FA70 mixture is related to an ECC sample with binder containing 70% FA by weight, whereas FA60-SF10 is the mixture with 60% FA and 10% SF. A total of nine ECC mixtures were prepared, and the details of the mix proportion are shown in Table 3.  
Figure 1: Flowchart of implementing prediction models for the self-healing capability of ECC.  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Chemical Composition (\%)** & **GPC** & **FA** & **LP** & **SF** \\ \hline Silica (SiO\({}_{2}\)) & 19.8 & 65.90 & 1.8 & 95.10 \\ Alumina (Al\({}_{2}\)O\({}_{3}\)) & 5.3 & 24.0 & 0.5 & 0.21 \\ Iron oxide (Fe\({}_{2}\)O\({}_{3}\)) & 3.0 & 2.87 & 0.6 & 0.29 \\ Calcium oxide (CaO) & 64.2 & 1.59 & 72.0 & - \\ Magnesia (MgO) & 1.3 & 0.42 & 1.0 & - \\ R\({}_{2}\)O & 0.6 & 1.93 & - & - \\ Sulfur trioxide (SO\({}_{3}\)) & 2.7 & - & - & - \\ Titanium oxide (TiO\({}_{2}\)) & 0.28 & 0.91 & - & - \\ Manganic oxide (Mn\({}_{2}\)O\({}_{3}\)) & 0.22 & - & - & - \\ Zirconia (ZrO\({}_{2}\)) + Hafnium (HfO\({}_{2}\)) & - & - & - & 3.46 \\ \hline Loss on ignition (\%) & 2.8 & 1.53 & 24.0 & 1.4 \\ Density (g/cm\({}^{3}\)) & 3.08 & 2.43 & 2.25 & 2.26 \\ Specific surface area (m\({}^{2}\)/kg) & - & 655 & 460 & \(1.5\times 10^{4}\) \\ \hline \end{tabular}
\end{table}
Table 1: Physical and chemical properties of cementitious materials.  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Length** & **Length/** & **Young’s Modulus** & **Elongation** & **Tensile Strength** & **Density** \\
**(mm)** & **Diameter Ratio** & **(MPa)** & **(\%)** & **(MPa)** & **(g/cm\({}^{3}\))** \\ \hline
8 & 200 & 42,000 & 7 & 1600 & 1.3 \\ \end{tabular}
\end{table}
Table 2: Properties of PVA.  
Figure 2: Particle size distribution of fine sand.