Synchrotron Microtomography and Neutron Radiography Characterization of the Microstruture and Water Absorption of Concrete from Pompeii

TL;DR

This study employs advanced imaging techniques like synchrotron microtomography and neutron radiography to analyze the microstructure and water absorption properties of ancient Pompeii concrete, revealing insights into its porosity, crack propagation, and permeability.

Contribution

It introduces a comprehensive methodology combining imaging and classical analysis to characterize ancient Roman concrete's microstructure and water absorption behavior.

Findings

Pompeii concrete has high porosity and low connectivity.

Crack patterns indicate ductile fracture behavior.

Permeability predictions align with pore structure analysis.

Abstract

There is renewed interest in using advanced techniques to characterize ancient Roman concrete. In the present work, samples were drilled from the "Hospitium" in Pompeii and were analyzed by synchrotron microtomography (uCT) and neutron radiography to study how the microstructure, including the presence of induced cracks, affects their water adsorption. The water distribution and absorptivity were quantified by neutron radiography. The 3D crack propagation, pore size distribution and orientation, tortuosity, and connectivity were analyzed from uCT results using advanced imaging methods. The concrete characterization also included classical methods (e.g., differential thermal-thermogravimetric, X-ray diffractometry, and scanning electron microscopy). Ductile fracture patterns were observed once cracks were introduced. When compared to Portland cement mortar/concrete, Pompeii samples had relatively high porosity, low connectivity, and similar coefficient of capillary penetration. In addition, the permeability was predicted from models based on percolation theory and the pore structure data to evaluate the fluid transport properties.