Archaeological Mortar Characterization Using Laser-Induced Breakdown Spectroscopy (LIBS) Imaging Microscopy

Area of Science:

• Archaeometry
• Materials Science
• Geochemistry

Background:

• Lime mortar, a historical building material, varies significantly in composition based on origin and use.
• Understanding these variations is crucial for building archaeology and cultural heritage preservation.
• Archaeological mortars offer insights into past construction techniques and material sourcing.

Purpose of the Study:

• To characterize the elemental composition of archaeological lime mortar samples.
• To investigate the potential of laser-induced breakdown spectroscopy (LIBS) for archaeometric analysis.
• To extract aggregate properties like granulometry and circularity from mortar samples.

Main Methods:

• Utilized a micro-laser-induced breakdown spectroscopy (µ-LIBS) instrument for elemental analysis.
• Applied image processing and mask creation for data extraction.
• Analyzed three lime mortar samples from diverse geographical locations (Angers, Dardilly, Pompeii) and building types (cathedral, aqueduct, house).

Main Results:

• Successfully characterized the elemental composition of the lime mortars.
• Identified the lime signature and the nature of the aggregates within the samples.
• Quantified aggregate granulometry and circularity using image analysis.

Conclusions:

• Laser-induced breakdown spectroscopy (LIBS) is a powerful technique for the archaeometric analysis of historical lime mortars.
• The study demonstrates LIBS's capability to provide detailed insights into mortar composition and aggregate characteristics.
• This research contributes valuable data for building archaeology and the conservation of cultural heritage.