## 3 Results and Discussion
### Mortars
The crushed ceramics have a hydraulic function, because the original clay minerals, during firing, become amorphous, and may react with the lime (calcium hydroxide) to form hydrated calcium silicates and hydrated calcium aluminates [17]. Lime hydraulicized with crushed ceramics, a heterogeneous structure, a micritic/microsparitic texture, and an absence of lumps were observed (Figure 9j). Figure 9: Microphotograph of thin sections of some selected mortar samples: (**a**) S1, (**b**) S2, (**c**) S3, (**d**) S5 (12–26) cm, (**e**) S5 (26–38) cm, (**f**) S13, (**g**) S14, (**h**) S7, (**i**) S6 and (**j**) S12 (by polarized optical microscopy; crossed nicols). The TGA analyzes were performed on representative samples: the selection was based on petrographic observations. The samples from attic: S1 (10-15) cm, S2 (9-14) cm, S3 (0-4) cm, S4 (4-20) cm; from the women's gallery: S5 (7-12) cm, S5 (12-26) cm, S5 (26-38) cm; and from the basement S8 (21-38) cm, S12 (0-4) cm, S14 (0-4) cm, and S16 (4-12) cm were analyzed. The variation of hydraulic behavior in the depth were evaluated in samples collected from the women's gallery (S5). Figure 10 shows the plot of the percentage of weight loss attributed to CO\({}_{2}\), as well as the percentage of weight loss attributed to hydraulic water (CO\({}_{2}\)/H\({}_{2}\)O ratio), and % CO\({}_{2}\), the significant parameters for identifying the type of binder used in the mortar mixture [24]. The presence of hydraulic components is registered through weight loss in the 200-600 \({}^{\circ}\)C temperature range, indicated as hydraulic water (%), the values of which range from 3.82% to 8.11%. The parameter %CO\({}_{2}\) is observed through weight loss in the 600-900 \({}^{\circ}\)C temperature range, and these values vary between 18.77% and 26.50%, resulting a material with a hydraulic behavior. The samples extracted from the same area present consistent hydraulic water and %CO\({}_{2}\) values. TGA results show that the samples from the attic, women's gallery, and basements of the Baptistery fall in the typical cluster of hydraulic mortars, and are characterized by a rather homogeneous hydraulicity. In the same cluster, but away from the other samples, S12, has a different setting reaction of binder (setting and hardening both through carbonation of calcium hydroxide and through reaction of calcium hydroxide itself with the hydraulicizing components), which is present in petrographic observation [17]. The S5 samples (analyzed at three different depths) show small differences among samples selected at different depths, suggesting that there is a slight variation of hydraulic behavior. The TGA results confirm the hydraulic behavior, as suggested by the presence of lumps of unburnt Albereese limestone in petrographic observations. The firing of maryl limestone provides natural hydraulic lime, typically produced in the Florentine area [19; 37; 38; 39]. Finally, the mortar samples show, mainly, the presence of lumps which are typical of Alberese limestone, suggesting the use of this stone to produce lime. Moreover, their presence in the mixtures testifies to traditional technologies. This raw material is able to confer to the mortar good performance, durability, and hydraulic behavior, as observed from the TGA results. Through the analysis of core samples at different depths, no substantial differences were found, and incomplete carbonation of the binder was observed in the deepest portion. The mortars of the Baptistery are composed of aggregate consisting of variable compositions (different amounts of monocrystals, carbonate, and silicate rock fragments)  
Figure 10: Plot of CO\({}_{2}\)/H\({}_{2}\)O ratio vs. %CO\({}_{2}\) measured on the enriched binders of mortar samples by TGA analysis. and abundance (B/A ranges from 1/1-1/2 to 1/3-1/4). In attic and basement samples, a predominance of carbonate rock fragments was registered. The macroporosity was medium in the attic and women's gallery mortar samples, and high in the basement samples, due to pores of irregular shape.