# Formulation of Alkali-Activated Slag Binder Destined for Use in Developing Countries
This author concluded that the mortars activated with Na2 SiO3 presented the highest strength, the lowest porosity and the finest pore structure. [PERSON] et al. [14] studied the influence of various factors, such as specific slag surface, curing temperature, activator concentration and the nature of activators. They concluded that an alkaline nature was the most significant factor in obtaining better mechanical strength. The best-employed activator as a mixture of Na2 SiO3 and NaOH to obtain mortars with compressive strength values over 100 MPa and flexural strength at around 12 MPa. BFS was classified as a moderately calcium-rich material that can be activated under relatively moderate alkaline conditions [15]. The main reaction products are gels CSH (calcium silicate hydrate) and CASH (calcium silico-aluminate hydrate), with the minor formation of hydrotalcite and some zeolites like gismondine [15; 16]. Generally speaking, the most widely used activators are NaOH and Na2 SiO3, or a mixture of both. For the BFS system, optimal pH values are around 13-13.6, and the addition of Na2 SiO3 normally causes greater development of mechanical strength compared to those systems activated with only NaOH. The silicate source reacts with Ca*2 from dissolved slag to form denser products [16]. The use of Na2 CO3 instead of other activators can be an environment-friendly and economical alternative for developing countries because it is 2-3 times cheaper than Na2 SiO3 and NaOH [17]. [PERSON] and [PERSON] [18] made a review on the application of alkali-activated slag and also considered Na2 CO3 the most appropriate activator. However, the long setting time and/or slow strength development make their use less appealing than the other activators [17]. Combining Na2 CO3 with other activators can improve AAS performance. For example, the use of MgO and Na2 CO3 mixture improves early strength and drying shrinkage in relation to those mortars that use only Na2 CO3 as an activator [19]. [PERSON] et al. [20] studied the effectiveness of employing calcined-layered double hydroxides to control the kinetics reaction of slags activated with Na2 CO3. These authors concluded that the addition of this reagent resulted in a faster setting and a better hardening process. [PERSON] et al. [21] explored the use of NaOH, Portland cement, and a mixture of silica fume and slaked lime as accelerators for systems BFS-Na2 CO3. Employing accelerators brought about an enhancement of 12 MPa in the mortars cured for 48 h vs. the control mortar. The majority of recent AAS research works have been conducted in developed countries rather than developing AAS to be used in developing countries with specifications of high-level technology and many material resources, especially chemical reagents. This paper aims to formulate an AAS that adapts to the specificities of developing countries, which exhibits rapid urbanization and considers local human and materials resources and existing infrastructures; for example, Sub-Saharan Africa. The ONU memberships formulated the Sustainable Development Agenda and included 17 Sustainable Development Goals (SDG) to protect the planet and to eradicate poverty [22]. SDG 11 proposesmaking cities inclusive, safe, resilient and sustainable, while SDG 13 is about climate action and claims regulating CO\({}_{2}\) emissions. To this end, AAS was formulated to be used in precasting as blocks or tiles that take into account the specifications of developing countries. The present paper investigates employing NaOH, Na\({}_{2}\)CO\({}_{3}\), and a mixture of both to prepare mortars with BFS as a precursor and preparing AAM to be utilized in developing countries.