The construction sector contributes significantly to the production of greenhouse gases and thus to climate change. This study aims to quantify the environmental performance of selected bearing constructions with special regard to their climate change contribution and resource depletion. Environmental impacts were assessed using environmental indicators, such as global warming potential and abiotic, water and natural resource depletion. The material composition of the wall structures consisted of aerated concrete blocks, ranging from 300 to 375 mm, with different thermal-insulation materials (expanded polystyrene with graphite, and rock wool) and variable interior and exterior plaster. The evaluation was based on life cycle assessment (LCA) methodology within the ‘‘cradle to gate” boundaries. The calculated values of global warming potentials per square metre of wall construction ranged from 234.16 to 283.46 kg CO_{2 eq} for the 20-year time span, from 213.02 to 255.20 kg CO_{2 eq} for the 100-year time span and from 190.40 to 229.90 kg CO_{2 eq} for the 500-year time span. The average water consumption was identified as 3.97 m³, and the abiotic depletion was identified as 1.41 kg Sb_eq per square metre of the wall structure. The lowest environmental impact in all environmental categories evaluated was found for a structure with aerated concrete with a thickness of 300 mm with graphite polystyrene thermal insulation and with silicone outdoor plaster. Using a suitable material composition of the wall structure, up to a 20% reduction in greenhouse gas emissions can be achieved while maintaining the same thermal parameters of the structure.

Sustainability in the construction industry refers to all resource-efficient and environmentally responsible processes throughout the life cycle of a structure. Green buildings may incorporate reused, recycled, or recovered materials in their construction. Concrete is as an important building material. Due to the implementation of by-products and waste from various industries into its structure, concrete represents a significant sustainable material. Steel slag has great potential for its reuse in concrete production. Despite its volume changes over time, steel slag can be applied in concrete as a cement replacement (normally) or as a substitute for natural aggregates (rarely). This paper focused on an investigation of concrete with steel slag as a substitute of natural gravel aggregate. Testing physical and mechanical properties of nontraditional concrete with steel slag as a substitute for natural aggregates of 4/8 mm and 8/16 mm fractions confirmed the possibility of using slag as a partial replacement of natural aggregate. Several samples of concrete with steel slag achieved even better mechanical parameters (e.g., compressive strength, frost resistance) than samples with natural aggregate. Moreover, a life cycle assessment (LCA) was performed within the system boundaries cradle-to-gate. The LCA results showed that replacements of natural aggregates significantly affected the utilization rate of nonrenewable raw materials and reduced the overall negative impacts of concrete on the environment up to 7%. The sustainability indicators (SUI), which considered the LCA data together with the technical parameters of concrete, were set to evaluate sustainability of the analyzed concretes. Based on the SUI results, replacing only one fraction of natural gravel aggregate in concrete was a more sustainable solution than replacing both fractions at once. These results confirmed the benefits of using waste to produce sustainable materials in construction industry.

High water absorption of recycled brick aggregate (RBA) is one of the most discussed parameters in terms of its application in the production of concrete—its influence on the amount of mixing water and, hence, the quality of the concrete, is usually considered negative. In this paper, different methods of decreasing the absorption of RBA and, consequently, the impact on the properties of concrete, are described. The RBA has been treated to decrease the water absorption capacity by impregnation approach using specific impregnators. Afterwards, the RBA samples have been dried at two different temperatures in the laboratory oven—20 and 90 °C. Concretes using 4/8 fraction of the treated RBA instead of natural aggregate (NA) have been mixed and tested. The effectiveness of the RBA treatments have been evaluated on the basis of their influence on the properties of the hardened concrete; by means of the following tests: flexural strength, compressive strength, capillarity, total water absorption capacity, depth of water penetration under pressure, and frost resistance. The method of ranking by ordinal scale has been used as it is suitable for the comparison of a large set of results, while results have been analyzed in terms of the most important technological parameter that influences the quality of the concrete-effective water content. Out of all the tested surface-treatments of RBA, treatment by sodium water glass has the best potential for reduction of the water/cement (w/c) ratio. When the effective w/c ratio is kept within standard limits, concretes containing treated RBA are possible to be specified for various exposure classes and manufacturing in practice. The experiment confirms that at a constant amount of mixing water, with decreasing water absorption of RBA, the effective amount of water in the concrete increases and, hence, the final properties of the concrete decrease (get worse). As the water absorption of the RBA declines, there is a potential for the reduction of the w/c ratio and improvement in the quality of the concrete.

The world faces a number of environmental issues. Many of these problems are man-made, the results of industrialization and building. There are many ways to help our world to become more environmentally friendly and healthier. Cutting back of carbon dioxide emissions by using less energy consumptive materials in the building industry is one of them. Waste products used as a replacement of old raw materials lead to the less energy consumption and cost saving. The tests results of energy waste (fly ash) exploitability as a partial cement replacement into the concrete cover of pavement is described in this paper. Compressive and flexural strengths at hardened ages of 7, 28, 90 days, chemical resistance, freezing and thawing of fly ash concrete composites were measured and compared with the reference specimen (C 30/37), which met the requirements of STN 73 6123 Building of road element.

The current annual worldwide production of by-products is estimated about 700 million tons of which 70 % is fly ash at least. Large quantities of fly ash are available at low costs around the world and its use in concrete seems to offer the best solution to reduce its consumption. With regard to these facts and Slovak needs, the chemical and mechanical properties of hardened concrete composites with various share of fly ash were studied. Other focus of this study is the investigation of the influence of different chemical admixtures on development of the concrete properties, their environmental and economic impacts