Analisi dei campioni prelevati dalla cupola del Duomo di Siena e dalle strutture limitrofe

From the observation in thin section of the samples taken from the internal nucleus of the wall the mortar is aerial lime mortar, made hydraulic by the abundant presence of cocciopesto; there is no evidence of the use of a hydraulic binder, but we do not have any remnants from firing either, to affirm with certainty which limestone was used. As regards the samples of mortar taken from the dome, there are great differences between samples TA1, DS B and DS 7a/b on one side and TA2 on the other. While the first three samples are very similar as to presence of carbonate binder, a well selected aggregate from the compositional and granulometric point of view (which is evident in samples TA1, DSB, a bit less in DS 7a/b where there is less selection), presence of lumps and microcracks, the sample TA2 has a cement binder.