3.1.5. Calorimetry

0%.

studies [13,41].

obtained by Topçu et al. [42].

Regarding the calorimetry analysis the registration of the hydration reactions of the mortars, through the software connected to the calorimeter device, it was then possible to plot the heat and thermal energy curves per unit weight of cement. Figures 8 and 9 present the values obtained. *Sustainability* **2022**, *14*, x FOR PEER REVIEW 16 of 26

**Figure 8.** Heat per unit weight of cement: Yellow curve with 30% and green curve with 0%. **Figure 8.** Heat per unit weight of cement: Yellow curve with 30% and green curve with 0%.

**Figure 9.** Thermal energy per unit weight of cement: Yellow curve with 30% and green curve with

By means of the thermal power curves, it was possible to observe in the sample with 30% substitution an increase in the curve in the acceleration period from 1.5 h to 5 h approximately, due to the faster heat release. This is directly associated with a nucleation process and growth of hydration products faster, a behavior also shown in previous

On the other hand, in the heat of hydration curves, it was possible to observe that the 30% sample presented higher heat of hydration accumulated since the beginning of the test, as a consequence of a greater formation of hydration products, a similar result to that

**Figure 8.** Heat per unit weight of cement: Yellow curve with 30% and green curve with 0%.

**Figure 9.** Thermal energy per unit weight of cement: Yellow curve with 30% and green curve with **Figure 9.** Thermal energy per unit weight of cement: Yellow curve with 30% and green curve with 0%.

0%. By means of the thermal power curves, it was possible to observe in the sample with 30% substitution an increase in the curve in the acceleration period from 1.5 h to 5 h approximately, due to the faster heat release. This is directly associated with a nucleation By means of the thermal power curves, it was possible to observe in the sample with 30% substitution an increase in the curve in the acceleration period from 1.5 h to 5 h approximately, due to the faster heat release. This is directly associated with a nucleation process and growth of hydration products faster, a behavior also shown in previous studies [13,41].

process and growth of hydration products faster, a behavior also shown in previous studies [13,41]. On the other hand, in the heat of hydration curves, it was possible to observe that the 30% sample presented higher heat of hydration accumulated since the beginning of the test, as a consequence of a greater formation of hydration products, a similar result to that On the other hand, in the heat of hydration curves, it was possible to observe that the 30% sample presented higher heat of hydration accumulated since the beginning of the test, as a consequence of a greater formation of hydration products, a similar result to that obtained by Topçu et al. [42]. *Sustainability* **2022**, *14*, x FOR PEER REVIEW 17 of 26

#### obtained by Topçu et al. [42]. 3.1.6. X-ray Diffractometry Analysis—XRD

Figure 10 shows that the particle size distribution of the OSPW particles dimensions is 88% between 2 µm and 60 µm. This class is considered as a filler. It was observed 10% of particles smaller than 2 µm, represented by D10 referring to fine quartz particles found by XRD. The particle size of the sand fraction is 2%, which is the coarser particle of the raw material. The residue is classified as non-plastic. These results are similar to those of Xavier et al. [5]. 3.1.6. X-ray Diffractometry Analysis—XRD Figure 10 shows that the particle size distribution of the OSPW particles dimensions is 88% between 2 µm and 60 µm. This class is considered as a filler. It was observed 10% of particles smaller than 2 µm, represented by D10 referring to fine quartz particles found by XRD. The particle size of the sand fraction is 2%, which is the coarser particle of the raw material. The residue is classified as non-plastic. These results are similar to those of Xavier et al. [5].

**Figure 10.** Particle size distribution of the ornamental stone processing waste. **Figure 10.** Particle size distribution of the ornamental stone processing waste.

Figure 11a presents the XRD pattern of the OSPW. Note that it is basically formed by quartz, identified by well-defined peaks. Figure 11b shows the presence of ettringite,

found between 22° and 26° (X-ray angle of incidence) in the CS sample, which shows a smaller amount of this stable and resistant phase. This shows that the waste contributes to the formation of this more resistant phase, as observed in Figure 8 with the increase in the heat of hydration being faster with the paste containing 30% of OSPW with the nucleation of the smaller particles, these being in amounts of 10% of OSPW fraction of 2 µm (Figure 10—OSPW particle size distribution). There is no difference between the COSPW

and CH2O paste when compared to each other.

Figure 11a presents the XRD pattern of the OSPW. Note that it is basically formed by quartz, identified by well-defined peaks. Figure 11b shows the presence of ettringite, portlandite, quartz and calcium carbonate. There is also an amorphous halo of C–S–H between 20◦ and 28◦ in the COSPW and CH2O samples. An amorphous halo of C–S–H is found between 22◦ and 26◦ (X-ray angle of incidence) in the CS sample, which shows a smaller amount of this stable and resistant phase. This shows that the waste contributes to the formation of this more resistant phase, as observed in Figure 8 with the increase in the heat of hydration being faster with the paste containing 30% of OSPW with the nucleation of the smaller particles, these being in amounts of 10% of OSPW fraction of 2 µm (Figure 10—OSPW particle size distribution). There is no difference between the COSPW and CH2O paste when compared to each other. *Sustainability* **2022**, *14*, x FOR PEER REVIEW 18 of 26

**Figure 11.** (**a**) X-ray diffraction patterns of the OSPW. (**b**) X-ray diffraction patterns of cement pastes. Legend: E (ettringite), P (portlandite), Q (quartz), C (CaCO3). **Figure 11.** (**a**) X-ray diffraction patterns of the OSPW. (**b**) X-ray diffraction patterns of cement pastes. Legend: E (ettringite), P (portlandite), Q (quartz), C (CaCO<sup>3</sup> ).

The above-mentioned difference is observed in Figure 7, from the squeeze flow, in the fresh state, as it requires less load and has a greater possibility of displacement, which means that the mortar with OSPW has more workability than the control mortar with only sand. In addition, there is a difference in intensity in most portlandite peaks between the COSPW and CH2O samples, with smaller peaks being observed in most of the COSPW samples. This may indicate a portlandite reduction and formation of stable phases, as discussed earlier. The above-mentioned difference is observed in Figure 7, from the squeeze flow, in the fresh state, as it requires less load and has a greater possibility of displacement, which means that the mortar with OSPW has more workability than the control mortar with only sand. In addition, there is a difference in intensity in most portlandite peaks between the COSPW and CH2O samples, with smaller peaks being observed in most of the COSPW samples. This may indicate a portlandite reduction and formation of stable phases, as discussed earlier.

#### *3.2. Technological Analysis—Hardened State 3.2. Technological Analysis—Hardened State*

larity coefficients of the mortars produced.

**Table 13.** Capillarity coefficients (g/dm2·min1/2).
