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In this paper, we proposed an alternative thermal treatment of sewage sludge, aimed at its application in blended cements, which can reduce the energy demands and requires less technologically sophisticated processing. The life cycle assessment (LCA) was performed to quantify the environmental impact of the sewage sludge used as a partial cement replacement. The LCA was focused on the CO2 emission and energy consumption. The functional unit of 1 m3 of blended mortars composed of Portland cement CEM I 42.5, silica sand, and thermally treated sewage sludge, where the sludge was used as partial cement substitute in a dosage of 10, 20, and 30% by mass of cement, was analyzed. The positive effect of the use of sewage sludge as a partial cement replacement with respect to the energy consumption and GHG emission, considering the compressive strength of the analyzed composites, was quite apparent. The decrease of energy consumption necessary for the production of the analyzed blended binders was nearly 10% per each 10% of sewage sludge used as Portland cement replacement. The energy needed for the sludge thermal treatment at 700degC was 220 MJ/t. The emission of GHG related to the sludge thermal treatment was 40kg/t. The presented data were strongly affected by the applied distribution of electricity sources, with a high share of coal combustion plants.

Due to the increasing amount of waste tyres and also to their properties, it is necessary to look for suitable ways for their recycling. For production of rubber concrete, the crushed tyre rubber of fraction 0/4 and 4/8 was used for partial substitution of silica sand at the rate of 10 % by mass. For comparison, a reference concrete without rubber aggregate was also studied. Both natural and rubber aggregate were first assessed in terms of their physical parameters and thermal transport and storage properties. Evaluation of produced lightweight rubber concrete included measurement of basic physical properties, strength tests, and microstructural analysis. Thermal properties were studied from dry to fully water saturated state. The experimental results showed that concrete with a small amount of rubber aggregate had improved thermal insulation performance and can serve as an eco-friendly material for structural applications in civil engineering.

Lightweight renders with improved thermal performance, resistant against moisture and respecting specific behaviour of original plasters and substrates became attractive materials for surface finishing of both historical and old wall structures. In this respect, structural, mechanical and thermal properties of cement-lime based renders containing a different amount of perlite as fine silica sand substitution are researched in the presented paper. Experimental tests conducted for 28 days samples showed significant lightening of hardened renders with increased perlite content in their fresh mix. Gained strength parameters were, because of higher total open porosity of perlite enriched samples, lower compared with reference material. On the other hand, newly developed lightweight renders exhibited improved thermal insulation performance due to the highly porous perlite particles. In summary, cement-lime renders with incorporated lightweight aggregate based on expanded perlite were considered as alternative and promising materials for application in repair and restoration of historical masonry.

Plastic waste and its low recycling rate make a significant contribution towards the pollution of the environment. Therefore, it is essential that plastic waste is utilised in different applications, such as aggregates in concrete. Since the coefficient of thermal expansion of polypropylene (PP) is significantly higher than for the ordinary concrete, the resulting mismatch in thermal expansion behaviour of the lightweight concrete can cause many problems, especially when the external temperatures reach the higher values. In this paper, an investigation of a manufactured plastic aggregate as a partial replacement for natural silica aggregate in concrete is presented. For concrete manufacturing, regranulated polypropylene (R-PP) waste coming from PP pipes production was used for the partial replacement of silica sand in concrete mix composition by 10, 20 and 30 mass % respectively. The studied materials were heated up to 120 degC. The basic physical properties before and after thermal treatment were studied. To analyse the thermal strain and the coefficient of thermal expansion of the studied materials, the horizontal thermodilatometry was applied.

Resource efficiency and building energy consumption is in recent years an open question for construction industry. Recycled plastic aggregate can be used as an alternative aggregate to produce lightweight concrete with low environmental impact of both concrete and waste plastic and moreover, the obtained lightweight concrete is characterized by improved thermal insulation properties. In the present study, waste expanded polypropylene (EPP) aggregate is used for partial replacement of natural aggregate to produce lightweight cement-based composites containing synthetic coagulated amorphous SiO2 as supplementary cementitious material. For the applied EPP, basic physical properties were measured and specific attention was paid to thermal transport and storage properties that were studied in dependence on compacting time. The effect of EPP content on the mechanical characteristics and on the thermal properties of developed material was investigated for 28 and 90 days water cured samples. Composite with incorporated EPP aggregates exhibits enhanced thermal insulation properties with sufficient mechanical resistance and can be considered as promising material for building subsoil or floor structures.

Waste glass in the form of finely grounded powder can be, due to its assumed pozzolanic behaviour, used in cement and concrete industry as a Supplementary Cementing Material (SCM) helping to reduce the consumption of natural resources and emission of greenhouse gases. In this sense, the presented paper is focused on the use of waste borosilicate glass in production of cement-based lightweight composites. For both Portland cement and glass admixture, chemical composition, pozzolanic activity and basic physical characteristics were accessed. In composite mixes, cement binder was partially replaced with glass powder in the amount of 15 and 20 mass %. In order to produce lightweight materials, foaming agent in the amount of 0.58 ml/kg of blended binder was used. For the developed materials, bulk density, matrix density, total open porosity, mechanical resistance, water transport parameters and thermal properties were tested The obtained experimental results revealed pozzolanic activity of micro scale milled waste glass that led to the decrease in porosity and thus improved mechanical resistance of the investigated composites. High porosity of foamed concretes significantly improves their thermal-insulation function and helps to save raw materials for their production.