Özet:

The material defined as "artificial stone", frequently used on the facades of the late 19th and early 20th century buildings, is a mixture of binder, aggregate and other additives and may either be applied directly as a coating on wall surfaces or precast in moulds and then attached to facades as decorative architectural elements. This new material and technique could not have been possible without a early modern scientific understanding of binders with hydraulic properties at the end of the 18th century and the development of new methods for their artificial production in the early 19th century. Early hydraulic binders included water limes and natural cements as well as the use of fat limes with artificial pozzolanic aggregates such as brick dust and ashes, a combination known since the Roman period that has remained in use through the Middle Ages. Many new cement types were formulated, patented and produced based on the chemical composition of the natural hydraulic limes in the 19th century. Although patented and named before the mid-19th century, Portland cements as we understand them today were not produced before the 1930s. Hydraulic mortars and concrete brought about an engineering revolution at the end of the 18th century when the first large-scaled water structures such as light houses, bridges and wharfs were constructed. But this new material was soon adapted to architecture as well and found a wide range of new applications both structural and decorative, and including the stone-imitating plasters or artificial stones that soon replaced the time-consuming and costly traditional stone masonry. The techniques of application and/or production may be summarized as follows: flat plaster coatings applied in-situ, which could be modeled with various tools, imitate ashlars with knifecut joints or be decorated with stamp moulds; architectural elements with decorative mouldings and friezes produced in-situ with running moulds; and architectural elements precast at the workshop, including load-bearing bricks, steps, lintels etc. as well as decorative elements such as balustrades, relief panels, sculptural elements and base-column/pilaster-capital combinations of various orders. The precast elements could be produced using a large variety of moulds, adapted for the different binder and mortars used.