Straw in Clay Bricks and Plasters—Can We Use Its Molecular Decay for Dating Purposes?

Abstract

Dating of clay bricks (adobe) and plasters is a relevant topic not only for building historians in the Pannonian region. Especially in vernacular architecture in this region, clay with straw amendments is a dominant construction material. The paper presents the potential of the molecular decay of these amendments to establish prediction tools for age based on infrared spectroscopic measurements. Preliminary results revealed spectral differences between the different plant parts, especially culms, nodes, and ear spindles. Based on these results, a first prediction model is presented including 14 historic samples. The coefficient of determination for the validation reached 62.2%, the (RMSE) root mean squared error amounted to 93 years. Taking the limited sample amount and the high material heterogeneity into account, this result can be seen as a promising output. Accordingly, sample size should be increased to a minimum of 100 objects and separate models for the different plant parts should be established.

Recent developments in using the molecular decay dating method: a review

“…It has also been applied to dating models (e.g., Refs. 13, 14, and 16). The field of machine learning bore several techniques with completely different statistical approaches.…”

“…FTIR spectra hint at a degradation process comparable with a piece several hundred years older. This might mean exceptional 15 and part of the wood (trunk, branch, 16 and root)…”

“…Straw is not a very common finding in an archaeological context, whereas it is quite common in clay constructions as an amendment for reinforcement 57 . Tintner et al 16 . presented a preliminary prediction model for age based on the MD of straw in clay bricks and plasters measured by using FTIR spectroscopy based on 14 historic objects spanning about 480 years with a prediction error of 93 years.…”