# Properties of Foamed Lightweight High-Performance Phosphogypsum-Based Ternary System Binder
## 3 Results and Discussion
### Properties of High-Performance Ternary System Binder and Mortar
#### 3.1.3 Physical and Mechanical Properties  
The bulk density of hardened binder is given in Table 4. The density of binder paste GCP-BG is slightly lower comparing to GCP-PG (1609 to 1766 kg/m\({}^{3}\)), which can be explained by the finer particle distribution for PG and denser structure of the paste. Similar tendencies were observed for mortar. The bulk density of a mortar material increased to 1886 and 2027 kg/m\({}^{3}\) for GCP-BG-S and GCP-PG-S, respectively. The total porosity for GCP-PG and GCP-BG was 23 and 29 vol.%, while for mortar it was even lower \(-11\) and 17 vol.% for GCP-PG-S and GCP-BG-S. The low porosity is associated with low W/B ratio, which is also similar to traditional concrete nature [19]. This phenomenon had an influence also on the compressive strength of the materials presented. The consistency of fresh material was strongly affected by the amount of superplasticizer and low water content. The initial mixing of binder powder with water and plasticizer gives stiff mixture while during the intensive mixing, the effect of superplasticizer takes place and very viscous mixture was obtained with flow diameter \(-295\) mm for GCP-BG and 370 mm for GCP-PG. The low W/B ratio of the paste (GCP-PG and GCP-BG) gives similar consistency as for ultra-high performance concrete [20]. The flow for GCP-PG was higher, which is associated with the finer particle nature of PG. The prepared mortar was less viscous comparing to paste while the effect of superplasticizer was also present and high workability obtained. The flow of mortar was from 210-230 mm. The setting time was longer for GCP-PG and GCP-PG-S as set retarder was purposely used in mixture composition. The initial setting time was from 130-165 min for binder paste and mortar \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Mixture**} & \multirow{2}{*}{\begin{tabular}{c} **Consistency by Suttard** \\ **Viscosimeter, mm** \\ \end{tabular} } & \multicolumn{2}{c}{**Setting Time, min**} & \multirow{2}{*}{\
\begin{tabular}{c} **Dry Density,** \\ **Initial** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Toral Porosity,** \\ **kg/m\({}^{3}\)** \\ \end{tabular} } \\ \hline GCP-PG & 370 & 165 & 280 & 1766 \(\pm\) 9 & 23 \(\pm\) 2.2 \\ GCP-PG-S & 230 & 130 & 170 & 2027 \(\pm\) 14 & 11 \(\pm\) 1.2 \\ GCP-BG & 295 & 70 & 130 & 1609 \(\pm\) 24 & 29 \(\pm\) 2.4 \\ GCP-BG-S & 210 & 75 & 85 & 1886 \(\pm\) 38 & 17 \(\pm\) 1.9 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Physical properties of high-performance ternary system binder. Figure 5: Energy Dispersive Spectroscopy (EDX) analysis of GCP-PG binder. (**a**) point positions analyzed by EDX, (**b**) element content in analyzed region. The final set time was longer for GCP-PG (280 min) than for mortar GCP-PG-S (170 min) as it was more viscous to initiate the set of the paste. GCP-BG and GCP-BG-S initial setting time was slightly influenced by the mineral additives (t\({}_{\text{in}}\) 70 and 75 min, respectively), while the final set time was longer for GCP-BG (130 min) and was reduced for mortar GCP-BG-S (85 min). The compressive strength results are given in Figure 6. The compressive strength increased during the water curing similar as for Portland cement binder. The strength after demolding at 24 h was similar among all samples (13-15 MPa). The further curing resulted in slower strength gain for mortars (GCP-PG-S and GCP-BG-S). At the age of 28 d, the strength of moist samples reached 50 MPa for GCP-PG and 30 MPa for GCP-BG. The strength increase was not observed between 7 and 28 d for GCP-BG. The mortar strength reached 26 MPa for GCP-BG-S and 43 MPa for GCP-PG-S. After sample drying, material strength increased significantly at the age of 35 d. The GCP-PG reached 88 MPa while GCP-PG-S mortar reached 50 MPa. Binder GCP-BG had 49 MPa and mortar GCP-BG-S had 39 MPa, respectively. The failure of the mortar was mostly in the transition zone of aggregate and binder. Such result is highly competitive and promising compared to traditional Portland cement mortars.