In a new format, the Architecture Specialty Group (ASG) held a morning session devoted to presentations by students and recent graduates of architectural conservation programs. These papers presented recent research work carried out by the students on a variety of thesis topics.
Jennifer Schork, a recent graduate of Columbia University now working with Integrated Conservation Resources, presented “New Insights into Dolomitic Lime Mortar.” Ms. Schork carried out a laboratory testing and instrumental analysis program to better understand the constituents and properties of dolomitic lime mortars. Dolomitic lime dominates the North American market for repointing mortars, although some may not be aware that they are using it or the affects that it has on the mortar. Ms. Schork’s research showed that dolomitic lime mortars can be 45% stronger than high calcium lime mortars, with the uncarbonated material (brucite: Mg(OH)2) perhaps contributing to this strength.
Casey Gallagher, a recent graduate of The University of Texas at Austin now with the Texas Historical Commission, studied “Biological Growth on the Alamo.” Ms. Gallagher posed three crucial questions in her research: 1) what is the biogrowth? 2) is the biogrowth damaging to the stone? and 3) do cleaning treatments previously carried out affect the stone? Through lab cultures and DNA analysis, species of cyanobacteria were identified on the Alamo stone. This can be particularly damaging to the stone because they are endolithic, penetrating underneath the surface of the stone, and they secrete amino acids, leading to stone deterioration. In addition, cyanobacteria have a hard sheath that is difficult to remove and they can tolerate long periods of desiccation and extreme heat, leading to recolonization. One year after the application of in situ cleaning tests using D2 Biological Solution, BioWash and water, there are not signs of recolonization. However, photographic records show recolonization after previous cleaning of the stone, and recolonization has also occurred in laboratory culture samples.
A testing program to evaluate “Fatigue Behavior of Adhesives for the Repair of Marble” was presented by Laura Michela, a current student at Columbia University. Ms. Michela’s research compared thermoplastic adhesives (Paraloid B-72, Paraloid B-48N and a 3:1 blend of Paraloid B-72 to Paraloid B48N), thermosetting adhesives (Epo-Tek 301-2 and Akepox 2000) and a sandwich of Paraloid B-72 used as a barrier coat with Epo-Tek 301-2. The broken portions of cylindrical samples of Vermont marble were readhered using the different adhesives and then subjected to repeated vibration to simulate fatigue. Some samples broke during the vibration, but the remaining samples were tested in 4-point loading. Some of the observations from the testing program are that all samples subjected to the repeated vibration experienced loss of strength, the samples repaired using thermosetting adhesives had higher strengths than the thermoplastic adhesive samples, and that some samples broke at an area of the cylinder where the adhesive was not present. The research built on previous work carried out by Columbia University conservation students. Areas of further research include looking at different thermoplastic blends, different solvents with the thermoplastic resins, different marble types and different load testing mechanisms.
Alex Kim, a 2009 graduate of the University of Pennsylvania conservation program who now works in the programs Architectural Conservation Laboratory, presented “Soft Vegetative Capping of Architectural Masonry Walls.” Although “hard” mortar capping is often used on exposed masonry ruin walls, mortar capping is prone to cracking, which allows moisture and vegetation ingress, leading to further deterioration of the wall. Mr. Kim’s presentation examined another approach to protecting exposed masonry ruin walls. “Soft” vegetative capping uses geosynthetic membranes, soil and gravel and vegetation to prevent moisture infiltration. It has the benefits of low maintenance cost, improved aesthetics and legibility and retractability. In situ tests performed at semi-arid sites in the southwest United States and central Anatolia show that there is reduced temperature fluctuation with soft capping compared to hard mortar capping. However, moisture infiltration below the waterproofing membrane was noted at one test site, pointing to the need for improved design and installation procedures.
The final paper of the student session was given by Jessica Kottke, a recent graduate of the University of Pennsylvania conservation program. Ms. Kottke presented “Three-Dimensional Laser Scanning for Imaging, Quantifying, and Monitoring Micro Stone Surface Deterioration at Heritage Sites.” Using the case study of work documenting two lion sculptures at the Merchant’s Exchange in Philadelphia, PA, Ms. Kottke showed that three-dimensional laser scanning was useful in creating a background image that could be annotated for condition surveying. However, given the limitations of resolution, it may be impractical to use the three-dimensional models created from laser scanning programs for monitoring changes over time.
Dr. George Wheeler, Director of Conservation at Columbia University, Fran Gale, Senior Lecturer and Director of the Architectural Conservation Laboratory at The University of Texas at Austin, and Frank Matero, Professor of Architecture at The University of Pennsylvania, made several key points that put the student research presentations in context. The thesis research presented during the session is typically only one part of on-going research and is often followed by additional research by other students as part of their theses. The research also often depends on partnerships with organizations such as the National Park Service or academic departments outside of the preservation programs.
Following the presentations of recent student research and answering of technical questions posed to the presenters, there was a discussion on the possibility of developing an annual forum for student presentations. All present in the session seemed to agree on the usefulness of the presentations by students and recent graduates from architectural conservation training programs of their research. A forum for presenting the work of recent student research is valuable to the development of both the emerging professionals, who get feedback from their more established colleagues, and to the experienced practitioners, who learn about recent research that may affect their work.
Two points of inquiry on the organization of a session for recent student research were debated: what venue is appropriate for a presentation of recent student research and who should participate at presenters. On the first point, most people present for the discussion agreed that a half-day session or even full-day session of student presentations held in conjunction with the ASG session of the AIC Annual Meeting is an appropriate venue. This year, funding to cover all student costs to present at the session was provided through the George Stout Memorial Fund, and it is hoped that similar funding will be available in future years.
The question of what criteria should be used to select potential presenters is more contentious. As presented by Frank Matero in his introductory remarks to the session, there are 24 programs that lead to a Master’s degree in historic preservation, and another 20 or so graduate programs in related fields that award certificates in preservation or conservation. There are ten Master degree programs with one or more courses in architectural conservation, but only a handful of these have a full curriculum in architectural conservation. A number of questions were left undecided, such as whether the opportunity to present papers at a student and recent student session should be limited to just those trained in a program with a full architectural conservation curriculum or open to those doing architectural conservation research in other programs, and whether the universities should preselect the papers submitted for presentation or the papers should be submitted by the students to a ASG program committee. These questions will likely be revisited during the ASG business meeting on Friday, May 14, and in future discussion by ASG members.