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Hemp-lime composite is mainly used as thermal insulation for walls. As a wall material, it is exposed to the influence of rainwater and groundwater through capillary action. Due to the high content of highly porous organic filler (hemp shives), the material is characterized by high water absorption. Despite the presence of a lime binder, the action of increased moisture may lead to the development of biological corrosion. It is advisable to look for ways to reduce water absorption. The study involved modification of the binder with the admixture of biopolymer in the form of gum arabic in the amount of 1% and 3% (as a partial substitute for the binder). It is a natural resin that hardens in air. The influence of the modification was verified on the basis of the mass water absorption and capillary rise tests using gravimetric and TDR method. [ABSTRACT FROM AUTHOR]

The hemp-lime composite is mainly used as wall insulation material in timber frame structures. Due to the highly porous aggregate in the form of hemp shives, this material is characterized by high water absorption. The absorbed water adversely affects the parameters of the composite, including the decrease in thermal insulation and mechanical strength parameters. The article presents an analysis of the influence of the modification of lime based binder with casein on the reduction of water absorption and capillary rise of a hemp-lime composite. Casein is a protein of animal origin, used in ancient times in lime mortars to improve their mechanical strength and resistance to water. The capillary rise test was performed using TDR probes (Time Domain Reflectometry) and the gravimetric method. [ABSTRACT FROM AUTHOR]

Moisture accumulation and transport in the building barriers is an important feature that influences building performance, causing serious exploitation problems as increased energy use, mold and bacteria growth, decrease of indoor air parameters that may lead to sick building syndrome (SBS). One of the parameters that is used to describe moisture characteristic of the material is water absorption coefficient being the measure of capillary behavior of the material as a function of time and the surface area of the specimen. As usual it is determined using gravimetric methods according to EN 1925:1999 standard. In this article we demonstrate the possibility of determination of water absorption coefficient of autoclaved aerated concrete (AAC) using the Time Domain Reflectometry (TDR) method. TDR is an electric technique that had been adopted from soil science and can be successfully used for real-time monitoring of moisture transport in building materials and envelopes. Data achieved using TDR readouts show high correlation with standard method of moisture absorptivity coefficient determination. [ABSTRACT FROM AUTHOR]