# Development of Passive Fire Protection Mortars
## 3 Results and Discussion  
### Steel Plate Specimens  
The typical temperature evolution in the tested SP (CM, DCM, DGMP, DGMV, and DRCM) subjected up to 900 \({}^{\circ}\)C as a function of time, is shown in Figure 9.  
Figure 9: Temperature evolution in the tested SP: (**a**) Specim 26 of CM; (**b**) Specim 30 of DCM; (**c**) Specim 36 of DGMP; (**d**) Specim 40 of DGMV; (**e**) Specim 48 of DRCM. It is possible to verify that the oven used in this experimental layout generated a heating curve (oven temperature curve) close to the desired heating curve (setpoint temperature). Thus, all specimens were exposed to a uniform and identical thermal action, making the tests comparable to each other. Between 0 and 35 min, there was a slow and gradual increase in temperature of the specimens (CM, DCM, DGMP, DGMV, and DRCM) up to 100 \({}^{\circ}\)C. This temperature evolution was influenced by the water content in the mortars, i.e., by the energy required to heat and evaporate the liquid/crystallized water existing in the mortar. After this process, there was a sharp increase in temperature between 35 and 75 min, depending on the thermal conductivity of the mortar and the heating rate. Finally, until the end of the test, there was a slight increase in temperature in the specimen before a steady state temperature distribution was reached. This type of thermal development in the specimens was common for all compositions tests. Based on the values obtained from the various tests carried out, it was possible to measure the average temperature on the inner surface of the steel plate of the specimen and thus establishing a direct relationship between the developed composition and its thermal protection capacity. The average values of the maximum temperature on the inner surface of the specimen's steel plate (thermocouple 1) are shown in Table 5.  
From the results presented in Table 5, it is possible to evaluate the thermal efficiency of the developed mortars: DCM, DGMP, DGMV, and DRCM, when compared with the best commercial solution tested (CM). Furthermore, it allows evaluating the influence of the size of the aggregates and the addition of silica micro- and nanoparticles on their thermal performance. The second column of Table 4 refers to mortars developed without NS and MS, in which the raw materials were obtained using the Los Angeles method (LA method). The temperature of CM was used as a reference for comparison (311 \({}^{\circ}\)C). The average temperature on the inner surface of the steel plate (ISSP) in the DCM, DGMP, DGMV, and DRCM mortars were 293, 310, 278, and 323 \({}^{\circ}\)C, respectively. These results show that the thermal protection provided by DCM, DGMP, and DGMV mortars were 5.8%, 0.3%, and 10.6% thermally more efficient than CM, respectively. However, the DRCM is thermally worse (3.9%) when compared to the CM. Finally, the compositions with vermiculite (DCM and DGMV) have better thermal efficiency. The fourth column of Table 5 refers to mortars developed without NS and MS, in which the raw materials used were obtained using the industrial mill method (IM method). The average temperature in the ISSP in the DCM, DGMP, DGMV, and DRCM mortars were 309, 325, 275, and 366 \({}^{\circ}\)C, respectively. When comparing the ISSP temperatures of the DCM, DGMP, and DRCM mortals made with raw material from Los Angeles milling with the ISSP temperatures of the same mortars made with raw material from industrial milling, there was respectively a loss of insulation capacity by 5.5%, 4.6%, and 13.3% on average. As for the thermal performance of the DGMV, there is a slight improvement in thermal capacity of 1.1%. Overall, these results demonstrate that the reduction in grain size of the