Environmental concerns are becoming increasingly more significant worldwide, thus creating the urgent need for new sustainable alternatives in the industrial sector. The present study assesses the fundamental properties of ceramic residue (CR) originated by demolition operations, specifically, the floor and wall tiles and sanitaryware furniture, for further incorporation in the construction sector, namely in alkali-activated binders, mixed with other better-known precursors - fly ash (FA) and ladle furnace slag (LFS). Different CR/FA and CR/LFS weight ratios were considered and analyzed by mechanical behavior and microstructural analysis, which included uniaxial compression strength (UCS) tests, Scanning Electron Microscopy (SEM), X-ray Energy Dispersive Analyser (EDX), X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). Results obtained showed that the combination of CR and FA or LFS, activated with sodium silicate, produced UCS values higher than 20 MPa and 59 MPa, respectively, after 90 days curing.

The environmental impact due to the overexploitation of nonrenewable resources, the processing and transportation of materials, and waste production is a global concern that the construction industry must urgently address, since it is among the greatest contributors. Earth construction can be seen as an alternative building solution, enhancing sustainability, despite traditional techniques being nowadays in disuse in most developed countries. Construction with interlocking compressed earth blocks (iCEBs) is a recently developed technique, put in evidence in the last few decades, for overcoming many earth construction limitations. Here, this technique is studied as a sustainable building solution for Northern Portugal, where the typical soils are sandy, granitic residual soils with low clay content. These soils typically demand cement stabilization to produce earthen materials, which compromise the sustainability of the construction solution. In order to improve sustainability, stabilization with hydraulic lime is proposed as a partial replacement of cement. For this purpose, the properties of the selected soil were characterized through a set of geotechnical tests, with different percentages of cement and lime in the mixture composition tested, concerning the compressive strength of the specimens. A mixture composed of 87.5% of soil, 7.5% of cement, and 5% of lime was shown to be the most suitable for producing iCEBs with adequate mechanical performance. The compressive behavior of the iCEBs masonry was characterized by testing prisms and wallettes, considering both dry stack and mortar joints cases. The obtained results showed that using mortar in the bed joints allows for the improvement of the compressive strength (a 5%–18% increase) and Young’s modulus (a 65%–92% increase) of the masonry. Thus, it can be concluded that masonry built with locally produced iCEBs and stabilized with cement and lime is a feasible building solution, for a sustainable earth masonry built from sandy granitic residual soils, where the mechanical behavior is substantially enhanced by using bed-joint mortar.