The effect of the addition of construction & demolition waste on the properties of clay-based ceramics

Waste glass and reclaimed brick are types of construction and demolition waste (C&DW) that could potentially be used as secondary raw materials in the production of ceramics. Ceramics based on clay, waste demolished brick (5-15 wt.%) and waste glass (5-20 wt.%) were produced by pressing (P = 68 MPa) and subsequently sintered at 900, 950, 1000, and 1050 ° C for one hour. The physical and mechanical properties of the ceramics obtained were evaluated. The addition of demolished brick decreased the density and mechanical properties of the clay specimens and increased the water absorption. The incorporation of waste glass improved the sintering behavior and its mechanical properties. The addition of 20 wt.% waste glass and 10 wt.% waste demolished brick into the clay matrix improved the flexural strength by up to 20.6 % and decreased the water absorption by up to 22 %. The approach presented promotes an opportunity to recycle construction and demolition waste into alternative resource materials, and represents a positive contribution to the environment

Manual for use of Al-containing residues in low-carbon mineral binders

Our society can no longer be imagined without its modern infrastructure, which is inevitably based on the use of various mineral and metallic materials and requires a high energy consumption. Parallel to the production of materials, as well as the production of electricity, huge amounts of various industrial and mining residues (waste/by-product) are generated and many of them are sent to landfill. The European Union (EU) aims to increase resource efficiency and the supply of ”secondary raw materials“ through recycling [1], inventory of waste from extractive industries [2], and waste prevention, waste re-use and material recycling [3]. Much of the industrial and mining waste is enriched with aluminium (Al) and therefore has a potential to replace natural sources of Al in mineral binders with a high Al demand. However, the use of industrial residue in mineral binders requires an extensive knowledge of its chemical composition, including potential hazardous components (e.g. mercury), mineral composition, organic content, radioactivity and physical properties (moisture content, density, etc.). This manual addresses the legislative aspects, governing the use of secondary raw materials in construction products, description of the most common Al-containing industrial and mining residue (bauxite deposits, red mud, ferrous slag, ash and some other by products from industry), potentiality for their reutilisation and its economic aspects, potential requirements/barriers for the use of secondary raw materials in the cement industry and a description of belite-sulfoaluminate cements, which are a promising solution for implementing the circular economy through the use of large amounts of landfilled Al-rich industrial residue and mining waste cement clinker raw mixture. This manual was prepared by partners of the RIS-ALiCE project. It provides a popular content, which targets relevant stakeholders as well as the wider society. Moreover, it offers education material for undergraduate, master and PhD students.Other links: [http://www.zag.si/dl/manual-alice.pdf

Self-healing of cement mortars based on fly ash and crystalline admixture

The actual study has followed the effect of fly ash and crystalline admixture on cement mortars' mechanical and self-healing properties. Three types of cementitious mortars composed of (i) 16 wt.% fly ash, (ii) crystalline admixture, and (iii) 16 wt.% fly ash and crystalline admixture were compared to the standard mortar (in compliance with EN 196-1). The capillary water absorption determined the sealing efficiency of the cracks over a period of time. The experimental results showed that by autogenous self-healing the standard mortar has a sealing efficiency of 40% after 28 days of treatment and 70% after 6 months of treatment, but the addition of fly ash and crystalline admixtures stimulated the autogenous self-healing. The best results showed the mortar (iii) containing 16 wt.% fly ash and crystalline admixture, where the sealing efficiency achieved 79% after 28 days of treatment and 98% after 6 months

The valorisation of selected quarry and mine waste for sustainable cement production within the concept of circular economy

The cement industry could potentially consume large amounts of solid industrial waste in order to improve its sustainability. The suitability of selected quarry and mine waste as secondary raw materials (SRM) was examined for the sustainable production of cement following the concept of a circular economy. The chemical, mineralogical, and radiological characterization of SRM was conducted in this study. Its potential use in low-carbon and low-energy belite-sulfoaluminate cement was investigated by incorporating the examined SRM into cement clinker. Various characterization methods were used to characterize the cement, including X-ray powder diffraction (XRD), thermal analysis (DTA/TG), and isothermal calorimetry. Depending on the chemical composition of the waste, lower or higher amounts were allowed to be incorporated into the raw clinker mixture for a targeted clinker phase composition. Among the samples, differences were observed in the phase composition of synthesized clinkers, which slightly influenced the reactivity of the cement but did not significantly change the compressive strength of the final product