| About this Abstract |
| Meeting |
Materials Science & Technology 2020
|
| Symposium
|
Art and Cultural Heritage: Discoveries and Education
|
| Presentation Title |
Cementitious Systems in Roman Reactive Glass Marine Concretes |
| Author(s) |
Marie D. Jackson, Cory L. Trivelpiece, Nanfei Cheng, Barbara Nash, Nobumichi Tamura |
| On-Site Speaker (Planned) |
Marie D. Jackson |
| Abstract Scope |
The beneficial corrosion of reactive volcanic glass in the pumiceous pozzolan of ancient Roman marine concretes produces cementitious systems that have maintained cohesion and resilience for two millennia. Long after hydrated lime (Ca(OH)2) was fully consumed through pozzolanic reaction, fluids percolating through the concrete structures dissolved residual alkali-rich volcanic glass and crystals in the pumice. Post-pozzolanic mineral cements, mainly phillipsite and Al-tobermorite, crystallized from these fluids -- refining pore space, repairing fracture surfaces, and preserving chemical resilience by incorporating cations and anions in their crystal lattices. Micrometer-scale maps of pumice clasts from the Portus Cosanus (1st C BCE), Baianus Sinus (ca. 55 BCE), Caesarea (30 BCE), and Portus Neronis (60 CE) concretes with synchrotron X-ray microdiffraction and microfluorescence experiments describe these post-pozzolanic cementitious fabrics. Results of parallel dissolution experiments with Campi Flegrei pumice in diverse solutions provide a geochemical framework for understanding hydrological processes in the ancient maritime concrete structures. |