## 3 Results and Discussion
### Adsorption/Desorption Isotherms of Dry Mortar References (Mix 1)  
According to the International Union of Pure and Applied Chemistry (IUPAC), a classification system for adsorption isotherms can be categorized into six types based on the isotherm shape [37].  
This type of adsorption is a type of physisorption, which is caused by the affinity of the nitrogen gas with the surface of each sample. A material is characterized by its adsorption isotherm curve, that is to say, the quantity of gas adsorbed, as a function of the ratio P/P\({}_{0}\), see Figure 3. The quantity of adsorbed gas intruded depends on the ratio P/P\({}_{0}\), on the temperature, on the morphology of the solid/gas interface.  
The analysis of the adsorption/desorption isotherms of the reference samples show that their configuration are close to types IV and V (Figure 3). According to the classification of IUPAC, these two types are associated with capillary condensation taking place in mesopores. Considering the classification of the type of hysteresis loop, they are close to types H\({}_{3}\) and H\({}_{4}\)[38]. The H\({}_{3}\) type hysteresis loop can be attributed to capillary condensation taking place in a non-rigid texture but is not characteristic of a specific porosity. This type of loop is, often observed with materials in powder form, or fine aggregates [39]. The H\({}_{4}\) hysteresis loop is often observed with materials with micropores in sheets, between which capillary condensation can occur. The isotherm with a hysteretic loop is obtained with mesoporous and/or microporous adsorbents in which capillary condensation occurs. During the desorption if the adsorbed gas condensed by capillarity is trapped, a hysteresis between the sorption and desorption curve is then observed. This effect is observed for all the reference samples.  
According to Figure 3, the reference samples prepared with the w/b ratio = 0.5 show completely similar hysteresis for all energy levels and they have the same trends. The isotherm curve of samples in the same series but with the w/b ratio = 0.6, it presents a slightly different hysteresis in terms of height, which shows the volume absorbed.  
The specific surface measurements on the reference materials (Table 6) clearly show that the increase in the w/b ratio from 0.5 to 0.6 leads to a clear increase in the specific  
Figure 3: Adsorption/desorption isotherms of reference samples Mix 1 with two W/b.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multicolumn{1}{c}{**BJH Adsorption Pore**} & \multicolumn{1}{c}{**BJH Desorption Pore**} & \multicolumn{1}{c}{**Difference**} & \multirow{2}{*}{**BET (m2/g)**} \\  & **Volume (cm3/g)** & & & \\ \hline WSA & 0.0089 & 0.0095 & 0.0006 & 2.12 \\ GGBS & 0.0022 & 0.0023 & 0.0001 & 0.70 \\ Cement & 0.0037 & 0.0044 & 0.0007 & 0.91 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Relationship between pore volume and specific surface area.  
surface from 9.63 to 10.59 m\({}^{2}\)/g for the lowest compaction energy (400 kN\(\cdot\)m/m\({}^{3}\)) and from 9.35 to 11.53 m\({}^{2}\)/g for the highest compaction energy (1000 kN\(\cdot\)m/m\({}^{3}\)). The results show that the effect of compaction on the evolution of the adsorption capacity of the tested mixtures remains visible but negligible compared to the influence of the w/b ratio. The contribution of compaction energy is thus negligible compared to the contribution of hydration.