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The suitability of two different low-grade kaolinitic clays and limestone locally available in Switzerland to produce a limestone calcined-clay cement at industrial scale was investigated. Firstly, the clays characteristics related to reactivity were presented. Then, the effect of calcined clays on cement performance was explored according to EN 197-5 and EN 197-1 requirements. Finally, the new cement was produced at industrial scale by using a Swiss cement plant equipped with a Lepol kiln for clay calcination and clinker production and used to manufacture 3 different concretes mixes for 3 different environmental exposure classes (EN 206). The concrete mixes were tested for mechanical and durability performance. The results show that the two calcined low-grade clays are suitable to produce a limestone calcined-clay cement classified as CEM II/C-M (Q-LL). Moreover, all the 3 concretes manufactured with the new cement meet the minimum mechanical and durability standard requirements of the corresponding exposure classes. [ABSTRACT FROM AUTHOR]

This paper presents the results of an experimental investigation which was carried out with the purpose of assessing the performance-related properties of self-compacting cement-bound mixtures to be employed in pavement foundations in road tunnels. The mixtures contained a significant quantity of recycled components and function-specific additives. Characteristics of the mixtures, which were produced in a concrete batch plant, were studied by means of laboratory and field tests. Investigated properties included flowability, compressive strength, resilient modulus and bearing capacity. It was found that mixtures prepared with a cement dosage of up to 100 kg/m3 possess the required properties of flowability, strength and stiffness. On the contrary, mixtures with higher cement dosages (150 and 200 kg/m3) fail to meet all the performance-related requirements as a result of their high long-term strength which jeopardises excavatability. Obtained results also highlighted the effects of the different components on the properties of the mixtures and led to the definition of acceptance criteria which can be adopted in actual construction works. [ABSTRACT FROM AUTHOR]

Featured Application: The research work presented in this paper may be of value for the management of sawing sludge in the context of a circular economy approach. Potential applications may occur in all modern infrastructures in which high-voltage cables are buried in the pavement subgrade. The management of sawing sludge originated from cutting operations of ornamental stones represents a challenging task as a consequence of its peculiar composition that includes non-negligible amounts of heavy metals resulting from the wear and tear of cutting tools. The aim of the research work presented in this paper was to investigate the feasibility of using these by-products as supplementary constituents of cementitious mixtures employed for the formation of Fluidized Thermal Backfills (FTB). These mixtures are designed and produced for filling operations in pavement subgrades in which high-voltage electrical transmission cables are buried for protection purposes. Two different types of sawing sludge were thoroughly analyzed from a physical and chemical point of view and thereafter employed for the laboratory production of four FTB mixtures. Then, these were subjected to thermal, mechanical, and environmental tests in order to verify their suitability for their intended use. All investigated FTB mixtures exhibited a satisfactory and stable thermal conductivity, and they also displayed enhanced stiffness properties in comparison to standard subgrade and sub-base materials. Controversial results were obtained with respect to environmental properties resulting from leaching tests, thus suggesting that further investigations are needed before any full-scale application can take place. [ABSTRACT FROM AUTHOR]