Hayen, K. Van Balen, D. Van Gemert
Since the Ancient Greeks and Romans lime has been the most important binder for the production of mortar in the building technology in Europe throughout many centuries. It is only by the introduction of scientific research in the field of building technology in the 18th and 19th century that gradually a new and stronger binder, known as cement, was introduced. By the beginning of this century the use of cement in the building practice had become that important, that lime as binder was only seldom used for the construction of new buildings and even so for the restoration of our cultural built heritage. At present almost all knowledge, gained by means of practice for many centuries, has been lost. For a sound restoration of our precious cultural built heritage the knowledge of the physical, chemical and mechanical behavior of this ancient binder is however essential.
As a result an extensive test program has been set up with as main objective the study of the physical, chemical and mechanical behavior of hydrated lime mortar. In a first approach the influence of the ‘traditional’ methods for slaking, the binder/aggregate ratio and the type of aggregates on the physical and mechanical properties of the mortar is studied. Three different production methods for the lime will be studied; commercially produced hydrated lime, wet and dry slaked quicklime. As for the binder/aggregate ratio three different ratio’s will be examined for two sand types with completely different grain size distributions; one mixture with a perfect filling of the pores in the sand matrix by the lime binder, one meager and one fatter mixture of sand with lime binder. The first results from this extensive test program will be presented and discussed.
Key words: heritage, restoration, lime mortar, slaking, granulometry, porosity