Investigation of the Effects of Re-burial on Materials Used at Archaeological Excavations to Separate and Mark Objects.

Institution
Studio Västsvensk Konservering (SVK).
Gamlestadsvägen 2-4 B2, 415 02 Göteborg. Sweden.

Co-ordinator
 BSc, BA Inger Nyström Godfrey. inger.nystrom@vgregion.se

Aim
In archaeology a number of modern products are used to separate, mark and support archaeological objects during excavation. These products are essential both for identifying and supporting the objects. Consequently the durability of these products are of great importance especially in a situation where finds are to be re-buried after registration and documentation. Knowledge of and information about the most suitable products and material to use not only improves the quality of cultural heritage management but also improves the efficiency of the work that are to be conducted, since the correct material can be used directly from the start of an excavation. The aim of this sub-project is therefore to investigate the degradation and durability of relevant products used by archaeology today, to compare and judge their usefulness in relation to reburials.

Method The study will include a wide variety of products and materials. The products can be placed in the following groups:

  • Products/material to separate objects, like boxes/containers, bags, nets and sacks.
  • Products/material for identification of objects like tags with stamped numbers and Dymo-band, but also written identification with pencil, waterproof filt-pen and ball-point pen (Svenskt arkiv, RA-AF 1992:4).
  • Products/material for binding, like different kind of cords.
  • Products/material for support and protection, like wadding, geo-textile and synthetic rubber geo-membrane

The study will thus mainly include a variety of plastics, like polyethylene (PE), polypropylene (PP), polyester, polyamide (nylon) and polyether/polyurethane. Dymo-steelband for marking will be tested and compared with plastic Dymo-band, likewise a wooden container will be tested in relation to a PE-container.

In-situ test
Nine units with samples will be packed and eight of them will be deposited in-situ. Each unit will contain three samples of each product (except for the PE-box). A ninth unit will be kept as a reference in ambient storage condition at SVK. Three units will be retrieved, one each year, during the first part of the project. Ocular, photographic and SEM-examination will be conducted along with written documentation. Tensile strength will be tested and result analysed on the samples in the third unit (that is after 3 years of reburial).

Accelerated ageing test
Eight products/material mentioned will also be tested by accelerated ageing tests. The aim of the accelerated ageing tests is to clarify the connection between temperature and ageing time in the specific environment and to determine the acceleration degree and length of life of some commercial products/materials The accelerated ageing will be accomplished in a reburial environment, using sediments from Marstrand. The ageing will be accelerated by heating to three different temperatures. The tensile strength of each aged material will be tested, evaluated and reported.

The accelerated ageing tests will be performed by SP, Swedish National Testing and Research Institute.

Analyses All samples will be carefully documented prior to deposition/accelerated ageing and after each retrieval session, using:

  • Photographic and written documentation
  • Ocular inspection and microscopically examination
  • SEM analyses
  • Tensile strength

List of products/materials to be tested:

  • Plastic box/container, HDPE
  • Box/container, wood
  • Plastic bags, "Minigrippåsar", PE
  • Plastic net, PE
  • Plastic vowed sacks, PP
  • Plastic labels (Dymo), PE
  • Plastic labels with pre-stamped numbers, polyether/polyurethane
  • Labels (Dymo), steel
  • Pencil
  • Waterproof filt-pen
  • Ball-point pen
  • Cord, polyester,
  • Cord, nylon
  • Cord, PE
  • Geo-textile, Class IV, PP
  • Geo-membrane, synthetic rubber, EPDM
  • Wadding, polyester

 

 

 

 

  

 

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Work in progress and results 2004

Work in progress and results 2003


 

 


Inger Nyström Godfrey