###### Abstract  
Copper slag is an industrial residue with a large unutilized fraction. This study presents the development of alkali-activated composites from a copper slag named Koranel\({}^{\copyright}\). The effects of metakaolinite, ordinary Portland cement (OPC) and surfactants were investigated. The reactivity of Koranel with potassium silicate solutions with molar ratio R = SiO\({}_{2}\)/K\({}_{2}\)O varying from 1 to 2.75, with 0.25 intervals, was investigated using isothermal calorimetry. The reactivity was relatively low at 20 \({}^{\circ}\)C; the reaction started after a few hours with a low silica modulus, to several weeks with the highest silica modulus. The substitution of Koranel by OPC (5 wt.%) or by metakaolinite (10-20 wt.%), both led to higher reaction heat and rate; meanwhile, the addition of 2 wt.% polyethylene glycol/2-methyl 2,4 pentanediol delayed the reaction time in the system containing metakaolinite. Raising the curing temperature from 20 \({}^{\circ}\)C to 80 \({}^{\circ}\)C shortened the setting time of the low reactive systems, from several days to almost instantaneous, opening perspectives for their application in the production of preperties composite materials. The use of carbon fabric as reinforcement in the alkali-activated matrix led to composite materials with flexural strength reaching 88 MPa and elastic modulus of about 19 GPa--interesting for engineering applications such as high-strength lightweight panels. copper slag alkali-activated materials; laminate composite; elastic modulus; flexural strength 4.0.0000-0000-0000-0000-0000-0000-0000-0000-00000-00000-00000-00000-000000-000000-  
mainly made of a woven fabric embedded as reinforcement in a finely grained cementitious matrix [1; 3; 6; 7]. The fabric (\"a manufactured planar textile structure made of fibers and/or yarns assembled by various means such as weaving, knitting, tufting, felting, braiding, or bonding of webs to give the structure sufficient strength and other properties required for its intended use\") [1] could be made of different type of materials including carbon, basalt, aramid, polyethylene (PE), polypropylene (PP), poly-vinyl-alcohol (PVA), glass and also cellulose-based natural fiber [4; 8; 9]. Ordinary Portland cement (OPC) has been commonly used as binder for cementitious matrices for TRC [2; 3; 10]. Research activities on other binder types, including alkali-activated materials (AAMs), have been performed to address sustainability issues or improve specific TRC properties [3; 11; 12; 13]. AAMs are materials enclosing binder systems resulting from the reaction of a solid or dissolved alkali metal source with a solid silicate powder, and they have the potential to reduce up to 70-80% CO\({}_{2}\) emissions compared with the cement industry if optimally formulated [13; 14; 15]. It is worth noting that the development of AAMs could also offer the possibility for upcycling industrial residues [16; 17]. For instance, about 2.2 tons of copper slag (such as Koral-rnel slag) are generated per ton of copper produced [18; 19]. Hence, the production of TRC from a cementitious matrix containing Koranel slag will contribute to waste management. Potential applications of TRC include facing and sandwich panels; thin-walled lightweight elements; lightweight constructions and complex civil engineering structures; repair of existing buildings and constructions; fire resistance; and high temperature performance materials [5; 20; 21; 22]. However, at variance to textile/organic resin-based composites, no prepreg with mineral matrix exists. Prepreg can be prepared and stored for a long period at low temperature and sold before the final shaping. Mineral-based matrices such as AAMs are generally subjected to relatively rapid setting time at ambient temperatures, limiting their flexibility. The development of a mineral-based matrix for TRC with storage flexibility comparable to that of organic resin will widen their potential applications.