| About this Abstract |
| Meeting |
MS&T22: Materials Science & Technology
|
| Symposium
|
Art and Cultural Heritage: Discoveries during the Pandemic Year
|
| Presentation Title |
Binder and Volcanic Aggregate Transformations in the Mortar of Tomb of Caecilia Metella Concrete, 1C BCE, Rome |
| Author(s) |
Marie D. Jackson, Linda Seymour, Nobumichi Tamura, Admir Masic, Gabriele Vola |
| On-Site Speaker (Planned) |
Marie D. Jackson |
| Abstract Scope |
The mortar of robust conglomeratic concrete that forms a subterranean corridor of the Tomb of Caecilia Metella, 1C BCE, Rome, records reactivity of volcanic aggregate components and calcium-aluminum-silicate-hydrate (C-A-S-H) binding phase long after pozzolanic production of C-A-S-H and consumption of (Ca(OH)2) were complete. Micrometer-scale maps of Raman and SEM-EDS spectroscopic analyses and synchrotron X-ray microdiffraction studies reveal that C-A-S-H is reorganized into wispy halos and tendril-like strands, some with nanocrystalline preferred orientation or, alternatively, split into elongate features with short silicate chain lengths. Chemical and structural destabilization occurred during excessive incorporation of Al3+ and K+ derived from leucite dissolution in the Pozzolane Rosse tephra aggregate. The intermittent toughening of interfacial zones of tephra aggregate with post-pozzolanic strätlingite and Al-tobermorite mineral cements and long-term remodeling of the C-A-S-H binding phase through beneficial hydrologic interactions with surface and ground waters added to the chemical and mechanical resilience of the ancient concrete structure. |