## 1 Introduction  
The high population growth and new global standards of modern construction require more demanding and sustainable infrastructures. Statistical trends estimate an increase in global cement production from 4.3 in 2015 to nearly 6.1 billion metric tons in 2050 [1,2], which would involve demolishing reserves of limestone, increasing global CO\({}_{2}\) emissions by around 7%, and conducting an energy-consuming process with an energy intensity of about 4.8 GJ [3]. Geopolymers, also named \"alkali-activated (AA) binders\", have been introduced as a promising alternative to Portland cement with a lower environmental impact, producing 60% less energy and approximately 80-90% less greenhouse gas [4, 5, 6]. The mechanism of producing geopolymers is a polymerization process that involves the chemical reaction of alumina-silicate materials (such as fly ash (FA), volcanic materials, ground granulated blast furnace slag (GGBFS), metakaolin (MK), etc.) in the presence of alkaline activators (such as sodium sulphate, calcium hydroxide, sodium silicate, etc. ), resulting in three-dimensional Si-O-Al chains/bonds: poly silate (-Si-O-Al-O-), poly silate-siloxo (Si-O-Al-O-Si-O), and poly silate-disiloxo (Si-O-Al-O-Si-OSi-O) [1,2,7-10]. Geopolymers/AA binders provide high mechanical strength, better resistance to corrosion/fire, and lower creep/shrinkage [11]. However, one major constraint associated with the use of geopolymer mortars on a commercial scale is their low-strength development at ambient temperature curing and the need for heat curing [12]. To overcome this problem, additives such as slag, lime, and ultrafine fly ash are being added during their geo-polymerization [13,14]. Research has been conducted on the fresh state and hardened properties of AA/ geopolymer materials and, to improve such properties, nanomaterials and other additives have been added [15-18]. The shrinkage deformation and cracking are more significant in geopolymer paste than in cement due to its lower porosity/pore diameter and quick curing/hardening. This elucidates the importance of improving the volume stability and durability of this material by adding shrinkage compensation compounds such as calcium oxide, calcium sulphoaluminate, and MgO [19-22]. Calcium oxide and calcium sulphoaluminate react violently in a high alkali environment and cannot achieve an excellent compensating shrinkage effect in geopolymers, suggesting the use of MgO, which can induce a self-healing ability [22-24]. More recently, cement-free alkali-activated engineered composites (AAECs) using polyvinyl alcohol (PVA) and other fibers that exhibit strain hardening and micro-cracking characteristics with satisfactory fresh state, strength, durability, and shrinkage characteristics have been developed as more green, sustainable alternatives to traditional engineered cementitious composites (ECCs) [1,4,25-20, 26-30]. The total substitution of cement with industrial by-products in AAECs decreases the energy investment, pollution, and use of virgin materials, which facilitates infrastructure sustainability through the simultaneous enhancement of durability and material greenness [1,31]. One-part ambient-cured AAECs produced using binary combinations of fly ash class C (FA-C) and ground-granulated blast furnace slag (GGBFS) with powder-form alkaline reagents and PVA fiber exhibited higher compressive strengths and ultrasonic pulse velocities, due to the formation of a combination of reaction products (C-S-H/C-A-S-H), compared to the mixture of amorphous (N-C-A-S-H/N-A-S-H) and crystalline (C-A-S-H/C-S-H) binding phases in their ternary (FA-C + FA class F -FA-F + GGBFS) counterparts [1]. An investigation on engineered geopolymer composites (EGCs) made of fly ash, GGBFS, fine silica sand, and a 2% volume fraction of two fiber types showed a significant increase in the tensile strength with the use of steel compared to polyethylene fibers [32]. In recent years, there has been a significant increase in the use of nanomaterials in concrete to achieve enhanced properties.