Carbon dioxide (CO₂) emissions associated with Portland cement (PC) production is ranked as the highest among the construction materials and it is estimated that 8% of the worlds CO₂ discharges is due to PC production. As an average, the production of PC clinker including calcination process generates 0.81 kg of carbon dioxide per one kg of cement. Hence, new approaches which limit the negative environmental impacts of cement production and are aimed at the development of advanced methodologies are introduced. Implementation of lower energy consumption materials in production, which could moderately substitute PC in binders, can be addressed as one of the probable methods in mitigating environmental risks. Therefore, alternative binders fit into the most promising solutions. Present research investigates the environmental impact of the building sector, if an alternative to PC binder is used. Life cycle assessment (LCA) was used in this research to assess the environmental impact of the alternative ternary gypsum-PC-pozzolan binder in the production of mortar, and the environmental benefits were calculated and compared to traditional cement-based building materials. Phosphogypsum was considered as a secondary raw material, as in the current approach it is collected in open stacks bringing environmental concerns. SimaPro LCA software with the Ecoinvent database was used for most of the calculation processes. Results indicate that with alternative binders up to 30% of energy can be saved and 57 wt.% of CO₂ emissions can be reduced, bringing positive impact on the construction industries contribution to the environment.

The construction industry is one of the largest emitters of CO₂ because the production of traditional building materials is highly energy-intensive and uses considerable amounts of raw materials. This research aims to decrease the negative environmental impact of the construction industry by providing biocomposites with a low environmental impact due to their bio-based components and efficient use of the materials through 3D printing. Agricultural waste products—hemp shives—are used in these materials as a filler together with three different types of fast-setting binders—magnesium, calcium sulphoaluminate (CSA) and those that are gypsum-based. The study determines the setting time and compressive strength of these binders, as well as the formation of biocomposites of different densities for different applications; extrusion tests and preliminary life cycle assessment (LCA) are also performed. Results show that biocomposites with hemp shives and fast setting binders have a possible application in 3D printing due to their shape stability and buildability, as well as relatively high compressive strength, which allows for load-bearing use at high densities and thermal insulation use at low densities, although printability at low binder content remains a significant challenge. Preliminary LCA results show that CSA and gypsum binders have the lowest environmental impact from the binders considered.

The utilisation of Portland cement has aroused tremendous concerns owing to its production exerting a lot of pressure on the environment. Alternative eco-binders have been developed to replace it, among which alkali-activated materials (AAMs) have drawn great attention, especially due to the possibility of encompassing industrial and agricultural waste, which significantly improves the sustainability and cost-efficiency of the material. Biomass wood ash (BWA) is a by-product generated from power plants and, along with the advocation for biomass fuel as a renewable energy resource, there have been increasing applications of BWA in building and construction materials. This review examines the use of BWA as a precursor source in AAMs. Due to its low chemical and hydraulic reactivity, more active binary precursors are usually introduced to guarantee mechanical properties. Whereas the increment of BWA content can have a negative influence on material strength development, it is still a promising and feasible material, and new approaches should be developed to improve the effectiveness of its utilisation. Currently, study of BWA-based AAMs is still in the beginning stages and more research is needed to investigate the effects of BWA characteristics on the property evolution of AAMs, focusing on the durability and analysis of eco-efficiency. Overall, this review provides a comprehensive overview of the characterisation of BWA and its potential applications in AAMs, and meanwhile, based on the analysis of present research trends, proposes some prospective directions for future research.

Using a zig-zag model the free damped vibrations of sandwich shells of revolution are investigated. As special cases the vibration analysis under consideration of damping of cylindrical, conical and spherical sandwich shells is performed. A specific sandwich shell finite element with 54 degrees of freedom is employed. Starting from the energy method the damping model is developed. Numerical examples for the free vibration analysis with damping based on the proposed finite element approach are discussed. Results for sandwich shells show a satisfactory agreement with various reference solutions.