The effects of crystallization of Na2SO4 and NaCl on the weathering of various granites

Four granites widely used in the construction and restoration of old buildings and monuments in Galicia (N.W. Spain) were subjected to sodium sulphate and sodium chloride crystallization tests in a climatic chamber under diverse sets of temperature aπd humidity conditions, including those of RILEM. The effects of manually working some of the faces of the tes...

Πλήρης περίληψη

Αποθηκεύτηκε σε:
Κύριοι συγγραφείς: Rivas T., Prieto B., Silva B.
Συλλογικό Έργο: International symposium on the conservation of monuments in the Mediterranean, International Group on the Conservation of Monuments in the Mediterranean Basin (I.G.C.M.M.), Community of Mediterranean Univ., ΕΜΠ, European Commission - Directorate General X, Intern. Centr. of Mediterranean Studies, Νομαρχία Δωδεκανήσου, Δήμος Ρόδου, ΤΕΕ - Τμ. Δωδεκανήσου
Κατηγορία Υλικού: Εισήγηση συνεδρίου
Γλώσσα: Αγγλικά
Γλώσσα περίληψης: Αγγλικά
Στοιχεία έκδοσης: ΤΕΕ , 1997
Πηγή:Νέες αντιλήψεις, τεχνολογίες και υλικά για τη συντήρηση και διαχείριση ιστορικών πόλεων και συνόλων (4ο:1997:Ρόδος, Ελλάδα) / / ed. A. Moropoulou, E. Zezza, E. Kollias, I. Papachristodoulou . τ.1
Θέματα:
Γενική θεματική ενότητα:ΤΕΧΝΟΛΟΓΙΑ ΥΛΙΚΩΝ
Διαδίκτυο:Το πλήρες κείμενο
Φυσική περιγραφή:vol.1, pp.271-281 : fig., tabl.
Βιβλιογραφία:Biblgr.:p.281
Εκδότης:ΤΕΕ
Περίληψη:Four granites widely used in the construction and restoration of old buildings and monuments in Galicia (N.W. Spain) were subjected to sodium sulphate and sodium chloride crystallization tests in a climatic chamber under diverse sets of temperature aπd humidity conditions, including those of RILEM. The effects of manually working some of the faces of the test samples, and of the orientation of the granite (taking the horizontal plane of the quarry as reference plane) relative to the direction of absorption of the salt solution, were also examined. Sodium sulphate (deposited as both thenardite and mirabilite) was the most aggressive salt, causing sand disaggregations and scaling. The intensity of sand disaggregations increased with the porosity of the granite and was greatest οn the worked faces. Scaling mostly affected sample faces parallel to the horizontal plane of the quarry. Sodium chloride only induced sand disaggregation, which increased in intensity with NaCI concentration, drying temperature, and granite porosity. Experiments with sodium sulphate solution alone showed that hydration of deposited thenardite to mirabilite could not be induced by increasing the humidity, but rather that mirabilite precipitated οn the thenardite crystals when fresh sodium sulphate solution was supplied. Once formed, the mirabilite rapidly reverted to thenardite, even at relative humidities above 8096. Similar experiments with solutions of sodium chloride showed that it crystallized as smaller crystals at 60°C than at 20°C, which contradicts the temperature effects observed in the salt crystallization tests. (AU)
ISBN:960-7018-59-1 (set)
960-7018-60-5 (τ.1)
Κωδικός DEWEY:660.284298 - (Κρυσταλλωση:Φυσικες διεργασιες:Χημικη μηχανικη)
552.3 - (Γρανιτες:Πετρολογια)
620.1122 - (Διάβρωση φυσικών λίθων:Αντοχή υλικών)
720.288 - (Συντήρηση μνημείων:Αρχιτεκτονική)
DEWEY Γενικού θέματος:620.11 - (ΤΕΧΝΟΛΟΓΙΑ ΥΛΙΚΩΝ)