Toward antiquity-inspired design in materials and construction: Insights into the production and durability of the ancient materials Egyptian blue and Roman concrete

Abstract

With increasing pressure on the global climate, there is a dire need to reduce the impact of both resource use and production of manufactured materials. In particular, modern ordinary Portland cement is responsible for up to 8% of global greenhouse gas emissions and offers a design life on the order of decades, requiring continued maintenance and reconstruction of buildings and infrastructure. Antiquity-inspired design, or examining past engineering achievements to inspire modern design, is a new paradigm through which properties of interest from ancient materials are understood and translated to new design applications. This thesis examines two ancient materials of interest, Egyptian blue and Roman concrete, to understand properties that can be translated to sustainable design.

First, visible-induced luminescence, a property of interest for photovoltaics and forensics, is mapped at the micron-scale in ancient Egyptian blue pigment samples. The luminescence is correlated to specific crystalline structures and production pathways, including a modern antiquity-inspired sample using non-traditional raw materials.

Next, the interfacial zone of aggregates within and cementing binder of ancient Roman mortars are characterized. Ancient Roman structures, produced with predominantly local materials, have remained standing for millennia in a variety of seismic and climatic conditions. High-resolution chemical and microstructural characterization techniques, including synchrotron micron-scale computed tomography, synchrotron x-ray diffraction, Raman microspectroscopy, scanning electron microscopy and thinsection petrography, map complex, heterogeneous dissolution processes throughout the cementing matrix of mortar samples. Samples from the Tomb of Caecilia Metella (First Century BCE) indicate that dissolution in the interfacial zone of volcanic aggregates (pozzolane rosse scoriae, fresh leucite and pyroxene) is not inherently detrimental to the mortars. Raman microspectroscopy maps the C-A-S-H binding phase in both pozzolane rosse mortars and lime-ceramic mortars from ancient water infras3 tructure of Rome and Pompeii. Finally, aggregate-scale lime clasts inform on possible production pathways for both the ancient mortar of the Privernum archaeological site and antiquity-inspired materials of the future.

This work provides a characterization framework for the study of ancient materials; introduces new insights into the durability of ancient Roman concrete; and identifies a path forward for sustainable, durable design in civil engineering.