The interest in passive construction that has low demand for thermal energy continues to grow every year. It is related to both the reduction in maintenance costs of buildings and the growing environmental awareness in societies. Passive houses are characterised by very good thermal insulation properties of their external partitions. This paper presents the results of tests on the thermal conductivity for three different types of building materials, assuming their use as thermal insulation. The materials were subjected to water absorption tests during long-term immersion. The purpose of this study was to simulate water absorption caused by long-term water exposure. The tests were carried out on a perlite concrete block, a sheet of polyurethane foam applied by spraying and expanded clay in a loose form in three different fractions. The tested insulation materials were selected due to their different form, structure, and porosity characteristics, which largely determined the value of the thermal conductivity. A perlite concrete block is a new, innovative product, of which manufacturer’s data are not yet available as the product is currently at the stage of detailed research. The results were analysed statistically and used in graphs to show the dependence of the value of the thermal conductivity on moisture content of the samples. The purpose of this study was to indicate the importance of the proper incorporation of insulation materials into buildings, their storage before construction and use in the post-construction phase. Building standards for passive houses place high demands on materials used. In order to fully enjoy the advantages of passive buildings, i.e., lower energy consumption and benefits for the natural environment due to lower consumption of energy generated from non-renewable energy sources, it is necessary to use certified building materials and ensure proper use of objects. The studies quoted in this paper indicate to what extent the influence of moisture content negatively affects the properties of insulation materials in external partitions.

These days, the use of natural materials is required for sustainable and consequently plus-, zero- and low-energy construction. One of the main objectives of this research was to demonstrate that pelite concrete block masonry can be a structural and thermal insulation material. In order to determine the actual thermal insulation parameters of the building partition, in situ experimental research was carried out in real conditions, taking into account the temperature distribution at different heights of the partition. Empirical measurements were made at five designated heights of the partition with temperature and humidity parameters varying over time. The described experiment was intended to verify the technical parameters of perlite concrete in terms of its thermal insulation properties as a construction material used for vertical partitions. It was shown on the basis of the results obtained that the masonry made of perlite concrete blocks with dimensions of 24 × 24.5 × 37.5 cm laid on the mounting foam can be treated as a building element that meets both the structural and thermal insulation requirements of vertical single-layer partitions. However, it is important for the material to work in a dry environment, since, as shown, a wet perlite block has twice the thermal conductivity coefficient. The results of the measurements were confirmed, for they were known from the physics of buildings, the general principles of the formation of heat and the moisture flow in the analysed masonry of a perlite block. Illustrating this regularity is shown from the course of temperature and moisture in the walls. The proposed new building material is an alternative to walls with a layer of thermal insulation made of materials such as polystyrene or wool and fits into the concept of sustainable construction, acting against climate change, reducing building operating costs, improving living and working conditions as well as fulfilling international obligations regarding environmental goals.

This study investigates the deflection behaviour of Bubble Deck slabs using numerical and experimental approaches. Two techniques—numerical homogenization and 3D cross-sectional integration—are applied to derive equivalent properties for simplified finite element models. A scaled slab specimen (1020×2040×60 mm) with a reinforcement mesh of Ø4 bars spaced at 30 mm (top and bottom) and plastic spheres (Ø40 mm, spaced at 60 mm) is tested under self-weight and a mid-span linear load. The slab, simply supported on two shorter edges, is modelled both in full 3D and using simplified 2D model with homogenized parameters. Experimental deflections are compared with numerical and analytical/theoretical predictions to validate the proposed techniques, demonstrating their effectiveness in simplifying structural analyses while maintaining accuracy.

Sulfate corrosion is a significant durability issue for concrete used in sewage and hydraulic infrastructure. In sulfate-rich environments, the formation of expansive products (e.g., ettringite and thaumasite) leads to a progressive loss of performance. Unlike conventional protection methods, which rely on surface-applied coatings or impregnation, this study examines the use of water-dilutable epoxy resins as an internal, volume-wide admixture dispersed throughout the concrete matrix to provide whole-body protection. The experimental program evaluated the mechanical performance, microstructure, and sulfate ion ingress/penetration dynamics of resin-modified concretes. The results suggest that using the appropriate amount of resin can limit the penetration of aggressive ions and slow the harmful changes associated with sulfate attack while maintaining the material’s overall performance. Overall, these findings suggest that water-based epoxy admixtures are a promising strategy for improving the durability of concrete in sulfate-exposed environments. They also provide guidance for designing more resistant cementitious materials for modern infrastructure applications.

The increasing production of solid waste and the scarcity of natural aggregates as a matter of fact have made waste recycling a necessity. One such waste, which is generated in large quantities, is slag. However, slag from incineration plants may contain harmful elements that adversely affect the physical, chemical and mechanical properties of cement composites. This study presents laboratory research results on the effect of slag from the Poznan Municipal Waste Thermal Conversion Plant (Poland) on the physicochemical properties of cement composites. The samples were analyzed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It was shown that the slag analyzed contained significant amounts of aluminum, which had a direct effect on the structure of the concrete. An example of this influence is the release of hydrogen during reactions, which causes swelling and cracking of the concrete and reduces its mechanical strength. The authors emphasize that waste aggregate (slag) can be effectively used in the production of concrete after appropriate processing that reduces the risk of adverse effects.

Waterborne epoxy systems enable a polymer phase to be introduced uniformly into cementitious materials, but their curing requirements differ from those of the mineral binder. Cement hydration requires moisture, whereas concentration and crosslinking of the dispersed epoxy phase require progressive removal of water. The study compared ten curing sequences for a mortar containing a two - component waterborne epoxy system at a polymer - to - cement ratio of 15%. All mixtures had identical composition and were evalua ted after 28 days; only the sequence of water, air and thermal curing was changed. The investigated regimes included continuous water curing, continuous air curing, water - to - air sequences of different duration, immediate thermal treatment, and thermal treatment introduced after an initial water - curing stage. Compressive strength was determined on halves of 40 × 40 × 160 mm prisms. Descriptive comparisons were supplemented with one - way analysis of variance at a significance level of 0.05. The curing regime had a statistically significant overall effect on 28 - day compressive strength (ANOVA, p < 0.001). The highes t mean value was obtained after 7 days in water followed by 21 days in air (S2, 28.4 MPa). Similar results were recorded for 14 days in water followed by 14 days in air (S1, 27.5 MPa) and for a sequence consisting of 5 days in water, 1 day at 60 °C and 22 days in air (S7, 26.9 MPa). Continuous water curing produced 19.3 MPa, whereas immediate unprotected thermal treatment followed by air curing gave the lowest value of 16.6 MPa. Relative to continuous water curing, the S2 regime increased the mean strength by 47%. The results show that neither permanent saturation nor premature drying is favorable for the investigated epoxy - cement system. An initial moist period supports development of the cementitious skeleton, while a subsequent air stage creates conditions for polymer - phase formation. Thermal treatment ca n be beneficial only when introduced after adequate initial hydration. The findings support formulation - specific design of curing sequences for waterborne epoxy - modified mortars rather than direct transfer of conventional cement - mortar curing procedures.