Heritage in the crossfire: Developing novel field-based methods for assessing ballistic impact driven deterioration of heritage stone

Gilbert, Oscar

Abstract

This PhD project aims to advance current understanding of the damage caused by ballistic impact into stone-built heritage monuments in arid Middle Eastern and North African climates. Damage was assessed through the development of novel rapid, non-destructive, in-situ techniques for assessing geo-technical metrics of impacted stone across varied impact conditions (target lithology, ammunition type, impact angle). Further to the damage caused by the initial impact, the risk that ballistic impact poses of exacerbating long-term deterioration of impacted stone caused by weathering processes was also studied.
The ultimate application of this research is the creation of a risk matrix and field methods that allow conservation professionals to triage stone-built heritage monuments most at risk of deterioration in the aftermath of armed conflict. This will aid in decision making when seeking to allocate time and resources to the heritage assets most at risk, in order to prevent greater deterioration. To achieve this aim, a variety of methods were developed, including surveys of damaged stone surfaces for rebound hardness and permeability, and Protimeter assessment for the detection of weathering agents. These surveying techniques were coupled with Ultrasonic pulse velocity analysis and photogrammetry to assess aspects of the exterior and interior damage to stone caused by ballistic impact and subsequent weathering. All these methods were portable and non-destructive, and thus well suited to the application of assessing immovable heritage sites damaged in armed conflict. Finally, the data collected using these methods was used to quantify the damaged caused by combinations of various impact conditions (lithology, impact angle, projectile, presence of weathering agents) to construct a risk matrix. This matrix can then be used to assess at-risk heritage stone in situ and prioritise those sites at greatest risk of deterioration.
Results demonstrate that the most important variable in determining ballistic damage to heritage stone is the target lithology and its mechanical properties, whilst impact angle and projectile construction also influence damage levels depending on target lithology. Damage to stone samples was found to be worsened when exposed to subsequent haloclasty weathering simulation, with lithology again being a key determinant of damage. Laboratory findings were further supported with field studies of damaged heritage sites at risk of weathering deterioration. Results from these show that the methods and risk matrix developed during this project are viable in a field setting, and the methods described here have already begun to be used in active heritage conservation projects. Therefore, this project represents an original contribution to the field of heritage science, having elucidated a little-understood risk factor which contributes to and exacerbates haloclasty weathering deterioration of heritage stone (namely, conflict driven ballistic impact). Further to this contribution to knowledge of conditions likely to exacerbate weathering deterioration, the research presented here has developed methods to identify and quantitively compare those sites most at risk of haloclasty weathering deterioration in the aftermath of conflict driven ballistic impact.

• Thesis Type: Thesis
• Deposit Date: Apr 6, 2023
• Publicly Available Date: Nov 28, 2023
• Keywords: heritage, conflict, weathering, built environment
• Public URL: https://uwe-repository.worktribe.com/output/10611589
• Award Date: Nov 28, 2023