# Reactivity Assessment of Modified Ferro Silicate Slag by R\({}^{3}\) Method
As an important finding, the authors suggested that the Frattini test was found to be the most reliable method to assess the pozzolanic reactivity due to the fact that the Frattini test evaluates the CH consumption (related to pozzolanic reaction). In the work of [PERSON] et al. [23], pozzolanic activity of metakaolin, silica fume, fly ash, and incinerated sludge have been studied using the Frattini test, the saturated lime test and the strength activity index. In this scenario, the authors stated that no significant correlation could be found between the SAI test and saturated lime test results. In the recent work of [PERSON] et al. [26], replacement of cement by Ferronickel slags (FNS) was investigated. It was observed that increasing the FNS content in the mix tends to decrease the compressive and flexural strength. Interestingly, the presence of higher silica content in the FNS leads to the formation of a higher polymerization degree of the silica chains in the C-S-H structures. In the recent work of [PERSON] et al. [27], pozzolanic activity of granulated copper slag modified with CaO (GCS) was studied. The following were the interesting findings: (1) Pastesynthesized with PC-GCS showed increased heat release after seven days and compressive strength at 28 and 91 days, and (2) TGA and SEM analyses showed more gel phases and less pores in PC-GCS paste. In the work of [PERSON] et al. [28], the impact of slag fineness on the reactivity of blended cements with non-ferrous slag by R\({}^{3}\) was examined. It was stated that R\({}^{3}\) isothermal calorimetry showed that the slag was similar in reactivity to siliceous fly ash and increasing the fineness increases the reactivity of the slag. Moreover, [PERSON] et al. [24] studied the pozzolanic reactivity of artificial pozzolanic materials by the Frattini method, Chapelle method, and SAI test. The reactivity was assessed for eight different materials of siliceous and aluminosilicates composition, and the authors stated that further investigation is needed to study the reaction mechanism of SCM due to the influence of clinker phases during the reactivity assessment. In the work of [PERSON] et al. [25], isothermal calorimetry, Chapelle test, Frattini test, and SAI test were used to assess the pozzolanic reactivity of Cu slag. The authors concluded that the pozzolanic activity of the Cu slag mainly depends on temperature, the curing age, and the specific surface area. In another recent work of [PERSON] et al. [29], porosity of reactive powder concrete (made with PC, copper slag, and additives) based on automated analysis of back-scattered-electron images was analyzed. However, the proposed analysis did not show similar results to the MIP data due to the different sizes and characteristics of the pores examined with MIP and back scattered electron images. The studies [21; 22; 23; 24; 25] used PC as an activator to study the reactivity of the SCM. Due to the influence of clinker phases on the reactivity assessment, only speculative conclusions can be made on the reactivity of the SCM. To overcome this drawback, a recent report [30] published by RILEM technical committee TC 267-TRM (which partly turned into the ASTM standard C1897-20 (2020)) proposed a novel method to evaluate the reactivity of SCMs. The method is termed as \"R\({}^{3}\)\", which stands for rapid, reproducible, and relevant. The method uses mixes of SCM, CH, and H\({}_{2}\)O, supplemented with alkali sulfate (SO\({}_{4}\)\({}^{2-}\)) and carbonate (CO\({}_{3}\)\({}^{2-}\)) resembling the pH of the alkaline pore solution created by PC. By using this method, the reactivity of the SCM can be easily quantified from measured heat release, bound water, and CH consumption. In this article, reactivity of Modified Ferro Silicate (MFS) Cu slag was assessed according to the novel R\({}^{3}\) model system reported in RILEM TC 267-TRM. Reactivity of the R\({}^{3}\) model MFS slag paste was compared with quartz filler and the widely used pozzolanic material siliceous FA and latent hydraulic SCM GGBFS.