An innovative hybrid cement, based on type F fly ash (FA), iron and steel slag (ISS) and Portland cement (OPC), is proposed in the present paper. The precursors were activated by powder-form elements – sodium sulphate or sodium chloride – forming what is known as a ‘one part geopolymer’ cement, which was then evaluated considering both mechanical and microstructural perspectives. Results showed that, in these conditions, the reactivity of the ISS is lower than that of the FA, with or without the presence of the activators. In the ternary pastes formed by 50%ISS +25%FA + 25%OPC and 25%ISS +25%FA + 50%OPC, with no activator included, both the ISS and the FA reacted due to its inherent pozzolanic activity. The presence of the powder-form activators increased the mechanical strength of the pastes (which are known as “hybrid cements”, since an activator and OPC are simultaneously present), relatively to the no-activator pastes. Furthermore, the inclusion of Na₂SO₄ or NaCl increased and decreased the activation rate, respectively, relatively to the equivalent binder hydrated with water (i.e. without the presence of an activator). Regardless, in both cases, strength values above 40 MPa and 35 MPa, after 28 days curing, were obtained. In the hybrid cements, the activators first reacted with the OPC phases; with the activator anions originating products such as calcium sulphate, ettringite or Friedel's salt (depending on the activator type), which increase the density of the matrix and, therefore, the resulting mechanical strength. Furthermore, in the presence of the Na⁺ cation, local NaOH is generated, increasing the alkalinity of the medium and, consequently, accelerating the reaction of the ISS and FA, which further improves the mechanical strength. Behind every combination, a C-(A)-S-H gel is the main reaction product.

本文提出了一种基于 F 型粉煤灰 (FA)、钢铁渣 (ISS) 和波特兰水泥 (OPC) 的创新混合水泥。前体由粉末状元素（硫酸钠或氯化钠）活化，形成所谓的“单组分地质聚合物”水泥，然后从机械和微观结构的角度对其进行评估。结果表明，在这些条件下，ISS 的反应性低于 FA，无论是否存在活化剂。在由 50%ISS +25%FA + 25%OPC 和 25%ISS +25%FA + 50%OPC 形成的三元糊剂中，不包含活化剂，ISS 和 FA 由于其固有的火山灰活性而发生反应。粉末状活化剂的存在增加了糊状物（被称为“混合水泥”，因为活化剂和 OPC 同时存在），相对于无活化剂糊剂。此外，包含 Na₂ SO ₄或NaCl 相对于用水水合的等效粘合剂（即不存在活化剂）分别增加和降低活化速率。无论如何，在这两种情况下，在固化 28 天后都获得了高于 40 MPa 和 35 MPa 的强度值。在混合水泥中，活化剂首先与 OPC 相反应；活化剂阴离子源自硫酸钙、钙矾石或弗里德尔盐（取决于活化剂类型），它们增加了基质的密度，从而增加了由此产生的机械强度。此外，在 Na ⁺阳离子，产生局部NaOH，增加介质的碱度，从而加速ISS和FA的反应，进一步提高机械强度。在每个组合的背后，C-(A)-SH 凝胶是主要的反应产物。