Between practice and rule: codification, testing and use of plain concrete in Dutch military architecture (1870s-1910s)

From the last decades of the nineteenth century until the dawn of the First World War, plain concrete was the main building material for fortifications in the Netherlands. Although the architecture and typology of those fortifications has been studied, the development of plain concrete itself has received only limited attention. Nevertheless, archival sources, historic handbooks and early construction regulations show plain concrete as a lively material, of which composition and recipes were tested and adjusted to meet the specific standards of military engineering. Over a short period of time, plain concrete underwent rapid evolution, manifesting in year-to-year variations in recipes and concurrent application of diverse concrete types at the same location. Considering this premise, the paper sheds a light on the development of plain concrete and related construction techniques in Dutch military architecture. Through the crossing of archival sources and on-site observation of case studies (i.e., the fortifications of Naarden), the emerging data show how the development of concrete served the specific military goals. Furthermore, the paper highlights how the work of military engineers was part of a general quest for knowledge in all fields of engineering, showing mutual contributions and collaborative knowledge advancements. Following this historical analysis, the examination extends to contemporary manifestations of damage in concrete constructions, contemplating potential correlations with historical construction techniques. Ultimately, it highlights how this knowledge can promote a better understanding of deterioration processes in relation to experimental construction methods, thus, supporting contemporary preservation practice.