3.1.2. Squeeze Flow

In view of the data obtained by the squeeze flow method, it is possible to elaborate the curves of the behavior of the material, guided by ABNT NM 15839 [25], which characterizes the workability level of the studied mortar. It is possible to analyze three workability phases: (i) the high workability being represented by the occurrence of the extension of the plastic deformation stage when the material is subjected to very low loads, registering transition to the hardening stage only in larger displacements; (ii) the low workability is characterized by the absence of the plastic deformation stage; and (iii) the medium workability is characterized by presenting variation of the load level as the plastic deformation occurs. It is noteworthy that, in mortars with medium workability characteristics, the material tends to flow and then interrupt the flow, being subjected to greater loads, and when they return flow, the load tends to decrease [26]. *Sustainability* **2022**, *14*, x FOR PEER REVIEW 10 of 26

> According to the dynamic squeeze flow test, the studied mortars were placed in an equipment composed of two parallel plates, where according to the variation of the time and speed parameters, the equipment recorded the data referring to force versus deformation, as shown in Figure 3. loads, registering transition to the hardening stage only in larger displacements; (ii) the low workability is characterized by the absence of the plastic deformation stage; and (iii)

> Figures 5–7 shows the results of the squeeze flow test for the mortars obtained from the diversifications regarding the type of cement (CP II, CPIII and CP V) and OSPW/sand replacement fractions (10%, 30% and 60% of OSPW), also considering the speed parameters (0.1 mm/s and 3.0 mm/s) of material compression. Observing the curve described by the results of Portland cement mortar types CP II, CP III and CP V, considering the mixtures with 10% of OSPW tested at speeds of 0.1 mm/s and 3.0 mm/s, they obtained similar results. the medium workability is characterized by presenting variation of the load level as the plastic deformation occurs. It is noteworthy that, in mortars with medium workability characteristics, the material tends to flow and then interrupt the flow, being subjected to greater loads, and when they return flow, the load tends to decrease [26]. According to the dynamic squeeze flow test, the studied mortars were placed in an equipment composed of two parallel plates, where according to the variation of the time and speed parameters, the equipment recorded the data referring to force versus defor-

> Thus, the squeeze flow test was performed in three different groups. The first one considered the CPII type cement, the second one considered the CPIII type cement and the third one considered the CP V type cement. The three groups were evaluated according to the incorporation of 0%, 10%, 30% and 60% of OSPW, under the variation of speed parameters (0.1 mm/s and 3 mm/s) and maximum force of 1 kN. mation, as shown in Figure 3. Figures 5–7 shows the results of the squeeze flow test for the mortars obtained from the diversifications regarding the type of cement (CP II, CPIII and CP V) and OSPW/sand replacement fractions (10%, 30% and 60% of OSPW), also considering the speed parameters (0.1 mm/s and 3.0 mm/sec) of material compression. Observing the curve described

> The definition of the groups occurred based on the parameters foreseen by the standard, in addition to the composition presented by each type of cement and also the effects observed in the variation of the incorporation of residue in the materials studied. by the results of Portland cement mortar types CP II, CP III and CP V, considering the mixtures with 10% of OSPW tested at speeds of 0.1 mm/s and 3.0 mm/s, they obtained similar results.

**Figure 6.** Squeeze flow test results—mortar with cement Portland type CPIII (%W represents the OSPW grade incorporated). **Figure 6.** Squeeze flow test results—mortar with cement Portland type CPIII (%W represents the OSPW grade incorporated). **Figure 6.** Squeeze flow test results—mortar with cement Portland type CPIII (%W represents the OSPW grade incorporated).

**Figure 7.** Squeeze flow test results—mortar with cement Portland type CPV (%W represents the OSPW grade incorporated). **Figure 7.** Squeeze flow test results—mortar with cement Portland type CPV (%W represents the OSPW grade incorporated). **Figure 7.** Squeeze flow test results—mortar with cement Portland type CPV (%W represents the OSPW grade incorporated).

Thus, the squeeze flow test was performed in three different groups. The first one considered the CPII type cement, the second one considered the CPIII type cement and the third one considered the CP V type cement. The three groups were evaluated according to the incorporation of 0%, 10%, 30% and 60% of OSPW, under the variation of Thus, the squeeze flow test was performed in three different groups. The first one considered the CPII type cement, the second one considered the CPIII type cement and the third one considered the CP V type cement. The three groups were evaluated according to the incorporation of 0%, 10%, 30% and 60% of OSPW, under the variation of The materials composed of cement type CPII, with a variation of 10, 30 and 60% OSPW/sand, subjected to the test with a velocity of 0.1 mm/s, presented different behaviors in the phase transitions. In particular, the CPII cement mortar, incorporated with 10% OSPW and 90% sand, registered a phase transition of 0.5 mm in the displacement axis.

speed parameters (0.1 mm/s and 3 mm/s) and maximum force of 1 kN. speed parameters (0.1 mm/s and 3 mm/s) and maximum force of 1 kN. This behavior may be associated with the increase in the presence of OSPW in the samples, which contributed to the material having its plastic characteristics accentuated according to the increase in the incorporation of the waste. According to the variation of the incorporation rate, from 30% to 60% of OSPW, the phase transition doubled.

It is noteworthy that the curves responded to a maximum load of 1 kN; therefore, the behavior of the materials tested, considering the different ranges of OSPW incorporation, was directly influenced by the displacement speed (0.1 mm/s), emphasizing sensitivity to segregation.

Considering the materials formed by cement type CP III, with variations of 10, 30 and 60% of OSPW incorporation, subjected to a test speed of 0.1 mm/s, it can be seen that the mortar with the incorporation at 10% of OSPW presented its plastic phase up to the mark of 0.80 mm of displacement. The mortar incorporated with 30% of OSPW behaved plastically until the record of 1.80 mm of displacement. The mortar with 60% OSPW incorporation presented the highest displacement value, registering 2.60 mm.

According to the change in the speed parameter to 3.0 mm/s, the behavior of the curves was significantly sensitive, as seen in Figure 6. Thus, in a comparative analysis between the curves obtained at 0.1 mm/s and 3.0 mm/s, it was observed that the materials subjected to the lowest velocity parameter reached the maximum displacement in the system with a load of 1 kN, varying between 1.0 and 4.50 mm. On the other hand, the materials tested under a speed of 3.0 mm/s showed punctual behavior, being the loads to reach the maximum displacement, conditioned to the composition of each mortar. Taking into account the average load of 1 kN, the variation of the maximum displacement of the samples varied between 1.80 and 9.0 mm.

The curve obtained from the squeeze flow test with mortar incorporated with cement of the CPV type generated a different result from the others, showing only the viscous flow phase. Comparing the curves of the CP II type mortars, with the CP III type and CP V, in both the percentage of 60% reached maximum displacement, reaching the mark of 9.0 mm.

The tested materials formed by cement of the CPV type, with the incorporation of OSPW in 10, 30 and 60%, subjected to the parameter of speed of 0.1 mm/s, and of maximum force of 1 kN, presented phase changes punctually in displacements 1.0 mm, 2.90 mm and 4.30 mm respectively. The largest displacement recorded was 6.30 mm, presented by the product with 60% OSPW incorporation. When the speed parameter was changed to 3.0 mm/s, the product with 10% OSPW incorporation presented a similar curve to the same product subjected at a speed of 0.1 mm/s. Additionally, the CPV-type cement mortar incorporated with 10% OSPW, subjected to a speed parameter of 3 mm/s, registered a variation in the phase transition range.

Considering the speed of 3.0 mm/s, it was noticed that the products with 30 and 60% of OSPW incorporation described similar curves in the squeeze flow test, behaving plastically up to a maximum displacement of 9.0 mm.

In general, it appears that the curves mainly present the stages of plastic deformation and hardening stage. The materials subjected to the squeeze flow test started their curves in stage 2, known as plastic deformation or viscous flow, subjected to small loads. According to the increase in the load, the displacement responded with its gradual growth. In the transition from stage 2 to stage 3, some mortars presented the transition phase in a short displacement space. On the other hand, other mortars showed the transition phase in the long displacement space. As observed in Table 3, as the amount of waste increases, the amount of water and the w/c ratio increase, converging the results of the curves in Figures 5–7.

From the point of view of viscosity, regardless of the type of cement, the curves are similar, despite the different values. It is noteworthy that the CPII curves with 30% of OSPW at 3 mm/s and 60% of OSPW and CPV with 60% of OSPW, both at 1 mm/s and at 3 mm/s, differ mathematically from the other curves, having similarities between them. Through linear regression, the equations presented in Tables 4–6 were obtained, which suggest that the fluid mortar behaves like a grade 2 Herschel Bulkley fluid, unlike the grade 1 Bingham fluid, according to [38], showing that the fluid was influenced by the addition of waste. It is observed that the linear coefficient of all equations is different from zero, that is, the initial yield stress occurred, differentiating these mortars from Newtonian fluids.



**Table 5.** Linear regression and coefficient of determination—mortar sample with CPIII.




Another observed fact is that the yield stress decreases with the increase in the amount of waste, regardless of the load speed and the type of cement, and the mortar tends to be more fluid, that is, to have a greater workability. Ying et al., [39] studied the incorporation of waste glass processing in the mortar, noting that its increased incorporation in the mortar also contributed to a better workability.

Considering the value obtained in the linear regression analysis for R<sup>2</sup> , it is possible to analyze the linear correlation of the variables force and displacement. For values above 95%, it is possible to infer that the variables have a positive linear correlation, i.e., the data are accurate.
