OPTIMIZATION OF HYDRATED LIME PUTTIES AND LIME MORTARS USING NOPAL PECTIN FOR CONSERVATION OF CULTURAL HERITAGE
Free (open access)
101 - 111
ANGÉLICA PÉREZ RAMOS, JOSE LUZ GONZÁLEZ CHÁVEZ, LUIS FERNANDO GUERRERO BACA, MIGUEL ÁNGEL SÁNCHEZ ESPINOSA, ANAÍ CHIKEN SORIANO
Hydrated lime as a putty has had a very important role as a binder for mortars and plasters in which hundreds of years of archeological, artistic, and historical heritage have been preserved. There is evidence that the Maya improved the properties of their mortars by adding gum from different Mayan tree barks during lime hydration process. This interdisciplinary investigation made it possible to demonstrate that nopal mucilage can optimize slaked lime properties during lime hydration process, starting from the idea that the cactus produces both, gums and mucilage. During the chemical experimentation, it was possible to isolate the main component of the optimal physical and chemical interaction between lime and nopal mucilage. The main objectives of this research were to rediscover the value of an ancestral production technique, to position hydrated lime putty as an attractive product to builders that work with historic structures by optimizing its properties and lime mortars' behavior, and to reduce hydrated lime putties production time, specifically by speeding up the aging process from months to hours. Rheological and mechanical experiments succeeded in proving that the pectin of the nopal has a direct influence on the slaking lime process, improving lime putties and mortars' properties. Lime putties and lime mortar specimens were tested in XRD (X-Ray Diffraction) and SEM (Scanning Electron Microscope 7800) where crystallographic changes related to the optimization of the properties of lime mortars and lime putties were verified. The results established a new paradigm for the slaking lime process as the main production phase for lime putties and their mortars. Nopal pectin improves lime putties and lime mortars' plasticity, mechanical strength and proclivity to carbonation, while it also produces a reduction in capillarity absorption and mortar cracks.
lime mortars, slaking lime, lime putties, nopal pectin, rheological, mechanical, lime properties, hydrated lime, mortar properties, Mayan