Development of advanced plasters for insulation and renovation of building constructions with regard to their hygrothermal behaviour

Abstract

Thermal insulation and renovation plasters are in still greater demand for the insulation and renovation of existing as well as new buildings. The main reason is the need for thermal protection with the purpose of reducing the energy consumption of existing buildings and the construction of near zero energy buildings. Suitable thermal insulation brings considerable savings in terms of energy costs and reduction of pollutants and emissions generated during heating. Protection of the environment and human health is also very important. Another reason is the need for the materials to be able to withstand increased humidity, which is a problem in older buildings.Research is aimed at developing materials which would be ecological, exhibit capillary activity, have an optimal ratio of thermal insulation and mechanical properties, high porosity, and low diffusion resistance.This paper describes the results of the development of plasters useable for thermal insulation and renovation of buildings and the study of their hygrothermal behaviour including a simulation of thermal and humidity conditions of a selected construction detail.Measurements and simulations showed that the newly developed mixtures had similar or better properties than the reference lime-cement plaster. The optimal mixture in terms of physical, thermal insulation, and mechanical properties was mixture 7 made with lime hydrate and fly ash 2. Simulations were run in the software THERM and WUFI so as to calculate the lowest surface temperatures for 3 different implementations of a jamb. The results showed that the newly developed plasters delivered markedly higher surface temperatures than the reference plaster, i.e. Mixture 1. All the new plasters tested in jamb detail 3 showed a surface temperature above 12.94 °C based on a determination of the dew point according to ČSN 73 0540–2 at a temperature of +21 °C and relative humidity of 60%.