The main aim of this paper is to carry out the environmentally based enhancement of a concrete mixture containing recycled materials whilst considering natural resource consumption as well as mechanical and thermal property levels. The developed concrete is intended to be used in mortarless masonry wall structures. Ten concrete mixtures with different types and replacement rates of recycled masonry aggregate and recycled expanded polystyrene were prepared, and their mechanical and thermal properties were experimentally investigated. It was found that the use of recycled masonry aggregate led to better thermal properties while maintaining sufficient mechanical properties. On the contrary, the addition of recycled expanded polystyrene did not significantly affect the thermal properties of concrete, but the mechanical properties considerably declined. For this reason, the recycled masonry aggregate is suitable to use as an aggregate for concrete masonry blocks for wall structures.

Sustainable building covers wide range of criteria including environmental, social and economy issues. Relative humidity of the internal environment belongs to the group of social criteria dealing with the quality of indoor microclimate and is one of the important indicators. Low humidity level can cause dry skin, throats and nasal passages and can cause annoying static electric sparks. High humidity level can lead to growth of moulds and bacteria and can cause condensation problems on the cold surfaces. Appropriate level of relative humidity can be operate by building service systems which increases operating energy in buildings and is sensitive to correct set up, control and monitoring. Relative humidity can be also influenced by the choice of building structures and structural materials without any operating energy. The paper summarizes latest research on the influence of relative humidity on health hazards and influence of building structures and structural materials on the relative humidity.

In this article, research on the sorption properties of clay materials in comparison with commonly used building materials is published. The topic is mainly focused on the dynamic sorption properties and their influence on the relative humidity in the indoor environment. The results of comparisons of clay structures, rammed earth panels, clay plaster, and unburned bricks, with commonly used building materials, concrete, lime plaster, and gypsum board are examined. Statistically evaluated results in the form of confidence intervals are presented and the rate of dynamic sorption is analyzed. It is clear from the results that clay materials have a positive effect on the rapid adsorption and desorption of air moisture in the interior of buildings. However, there are many variables, band not every clay material has such excellent sorption properties.