# The Mortars of Florence Riverbanks: Raw Materials and Technologies of _Lungarni_ Historical Masonry
## 5 Results and Discussion  
### Chemical, Minero-Petrographic Results  
The main mineralogical and petrographic characteristics of the analysed samples are summarized in Tables S1 and S2, respectively. The minero-petrographic data carried out on the finer portions (mortar) of the samples extracted from cores of _Lungarno degli Acciaiuoli_ and _Lungarno delle Grazie_ show similarities and differences. Mineralogical analysis indicates the presence of calcite (CaCO\({}_{3}\)) referred to the binder and aggregate fractions; this is due to the presence, in the aggregate, of carbonate fragments of rocks and single calcite crystals. Other minerals present in the aggregate are quartz (SiO\({}_{2}\)), plagioclase ((Na,Ca)(Si,Al)\({}_{4}\)O\({}_{8}\)), micas (muscovite), and clay minerals (clinochlore and montmorillonite). K feldspars are present only in the samples C5-W and C10-Y. A calcium aluminium silicate (tobermorite, Ca\({}_{5}\)Si\({}_{6}\)O\({}_{16}\) (OH)\({}_{2}\)-4(H\({}_{2}\)O)) was recorded in cores C11-X and C13-X. Tobermorite was also present in the lumps extracted from cores C2b-Y L2, C3-X L, C7-X L, and C13-X L. Vaterite, a polymorph of calcium carbonate, was identified in C7-X and the lumps extracted from C2b-Y and C13-X samples. Tobermorite and vaterite can be found in natural hydraulic lime [38; 48; 49] and pozzolanic ancient roman mortars [50; 51]. Gypsum (CaSO\({}_{4}\cdot\)2H\({}_{2}\)O) was registered in samples C5-Z and C5-W and in the lumps of samples C2b-Y, C3-X, and C13-X. Ettringite (Ca\({}_{6}\)Al\({}_{2}\)(SO\({}_{4}\))\({}_{3}\)(OH)\({}_{12}\cdot\)26(H\({}_{2}\)O)) was detected in sample C5-Z and can be ascribed to the rection between cement phases and water [52]. In Figure 4a, a representative diffractometric pattern of a lump extracted from the core of the C2-X sample is shown; calcite, vaterite, tobermorite and gypsum were identified. Moreover, analyzing the lump via FTIR analyses concerning the wavenumber from 4000 to 400 cm\({}^{-1}\) (Figure 4b), the XRD composition was confirmed; in fact, the presence of tobermorite is highlighted in the spectra. Figure 4: XRD pattern of sample C2-X lump. The most intense peaks for calcite, vaterite, tobermorite and gypsum are indicated (**a**). FTIR spectra of sample C2-X lump. The vibrational bands of tobermorite are highlighted (**b**). The petrographic observation performed on _Lungarno degli Acciaiuloli_ samples reveals a binder for samples C2-X, C2b-Y, C3-X, and C6-Y with heterogeneous structure and micritic/microsparitic texture (Figure 5a-c,f). Some areas with low birefringence color were also identified. Lumps are present as remnants both of not well mixed binder and of overburnt limestone fragments in samples C2-X, C2b-Y, and C3-X. The aggregate is very abundant, not well selected, with a heterogeneous grain size distribution, and composed of quartz (mono and polycrystalline), plagioclase, K feldspar, calcite, arenaceous rock fragments, siltstones, and marly limestone fragments. The sample C5-Z was obtained mixing a hydraulic binder with abundant aggregate (B/A 1/3) and has a very heterogenous composition (Figure 5d). Remains of unhydrated clinker grains have been identified. Quartz (mono and polycrystalline), plagioclase, K feldspar, arenaceous and carbonate rock fragments, siltstones, and magmatic and metamorphic rock fragments were identified under an optical microscope. The grain size distribution varies in the range of 1-2 mm for rock fragments and 100-800 um for monocrystals. The shape is sub angular/sub rounded. A low macroporosity, due to microcracks and pores of irregular and rounded shape, was observed. The C6-Y sample also contains few fragments of magmatic rocks (Figure 5f). The rock fragments have a pluri-millimetric size, while the monocrystalline portion ranges from 100 to 500 um, shaped from sub-angular to sub-rounded. The macroporosity is of medium/high amount due to microcracks and pores of irregular and rounded shape.