This paper describes the use of cement‐based waterproofing screed and waterproofing coating, in which 10% of the original amount of cement was replaced by fly ash and 2% of the crystallization admixture was added by weight of cement, as a mean of protection of concrete against aggressive environments. The modified materials were applied to the underlying concrete and subjected to testing of physical and mechanical properties after exposure to effects of aggressive environments for up to 18 months. The results of the analysis have shown that after the application of waterproofing materials, there is a sufficient development of the crystals in the underlying concrete to enhance its durability. Thus, it is possible to use fly ash functionally and efficiently in polymer cement systems as a substitute for the cement together with the crystallization admixture.

This article presents research on the behavior of cement-bonded particleboards under mechanical stress caused by the static load. The composition of the boards was modified using alternative raw materials–dust (DU) forming during the processing of cement-fibre boards and particle mixture (PM) generated in the production of cement-bonded particleboards. The particleboards (1-year-old) were subjected to an adverse environment (100 to 250 frost cycles). Mechanical parameters were tested, and the development of defects during static load of the boards by bending was analyzed using acoustic emission. Particleboards with modified compositions are slightly more resistant to adverse environments. The results of the acoustic emission showed the different types of defects occurring under stress by bending. Standard-composition particleboards showed defects located mainly under the cylindrical stress-test head. The modified boards showed larger location distribution of the occurring defects that were also concentrated further away from the cylindrical stress head. The energy during the occurrence of defects was higher in the modified boards in the location of weight application than in the reference boards.

Limestone (LS) and stabilised secondary spruce chips (SCs) utilisation in wood–cement composites is still an unexplored area. Therefore, the main objective of the research presented here is the assessment of the long-term behaviour of cement-bonded particleboards (CBPs) modified by LS and SCs. Cement (CE) was replaced by 10% of LS, and spruce chips by 7% of SCs. The test specimens were stored in a laboratory and exterior environment (Middle Europe) for up to 2 years. The density, strength, and modulus of elasticity were evaluated after 28 days, and then in 6-month periods. The hygroscopicity was analysed separately. The mineralogical composition and microstructure were analysed due to possible LS participation during hydration. SC synergic behaviour in CBPs was also studied. After 2 years, the microstructure of the CBP was more compact, and denser. Strong carbonatation contributes to the improvement of CBP properties. The products of carbonatation were present in both the matrix and wood chips. The hydration of the matrix was almost finished. LS has a positive effect on the matrix microstructure development. LS acts both as an active component participating in the formation of the cement matrix structure and as an inert microfiller, synergic with hydration products. SCs have a positive effect on the hygroscopic behaviour of CBPs and slightly negative effect on the tensile strength.

Straw has been used as a building material since time immemorial and has been considered as a waste product from the agricultural sector, usually used for feed, bedding, or fertilization. Nowadays, the construction industry strives to reduce greenhouse gas emissions and is focusing on renewable materials; hence, straw seems to be an attractive, low-energy option. Straw bales or blown insulation are common uses, with limited detailed knowledge regarding the properties of different straw types. Straw is made up of the dry stems of crops. Straw’s chemical composition will differ with different crops and can have a great impact on its effectiveness. As a renewable material, straw also has the potential to be used in buildings, enhancing thermal insulation and reducing environmental impacts. This study considers four kinds of straw: barley, oats, oilseed rape, and triticale, regarding their possible usage in insulation materials. The thermal conductivity, bulk density, and dust generation of each type were tested in the laboratory. Among them, the best performance was shown by the barley straw treated with mechanical pulping using a knife mill at 4000 rpm for 60 s, which showed the lowest bulk density and thermal conductivity and generated the least dust. It is thus proven to be an environmental insulation material with significant implications for sustainable construction and energy-efficient building design, further helping in maintaining environmental sustainability in building construction.

This article addresses the potential use of secondary polymer fibres in the field of structural concrete as a replacement for primary polymer fibres (mainly polypropylene/PP/), which are used in concrete to enhance its resistance when exposed to high temperatures (especially in the case of fire). Research has shown that, in addition to PP fibres, polyethylene terephthalate/PET/fibres, produced by recycling packaging materials (mainly PET bottles), can also be used as an alternative. These fibres are industrially produced in similar dimensions as PP fibres and exhibit similar behaviour when added to fresh and hardened concrete. In terms of their effect on increasing resistance to extreme heat loads, it has been found that despite a higher melting point (Tm), concrete with these fibres demonstrates comparable fire resistance. Therefore, it can be concluded that secondary PET fibres represent an interesting alternative to primary PP fibres from the perspective of a circular economy, and their use in construction represents a potentially valuable application for PET obtained through the collection and recycling of PET packaging materials.