Cement, Energy and Environment

20 sample to assess the performance of GEOFS as a cement additive. Digital images of EOF slag, GEOFS, GGBS, OPC, and PSC 3 have been 3.2 MATERIALS CHARACTERIZATION Optical Microscopy: Fig. 2 demonstrates the optical microscopy images of GGBS (a) and GEOFS (b). The particle size chosen for this analysis of both materials are 90 µ < sample < 45 µ. In this figure, most of the GGBS particles were found transparent. This supports the glassy amorphous nature of GGBS. Again GEOFS has demonstrated glittering colorful particles. This implies the birefringence properties of crystalline particles. Hence it can be assumed that GEOFS is predominantly crystalline. XRF Analysis: Table 2, has demonstrated the elemental compositions of GEOFS and GGBS in the form of corresponding oxides, derived from XRF analysis. From this result, it has been found that the CaO and SiO2 content of GEOFS are 31.53 % and 13.13 %. The other major oxides are Fe2O3 (20.20 %), MgO (18.33 %), Al2O3 (4.87 %), MnO (3.48 %) etc. From this composition, it has been found that the ratio of CaO and SiO2 content is 2.37. So at molten condition, CaO and SiO2 may combine for some calcium silicate-based cementitious phases like Dicalcium silicate, tricalcium silicate, etc. Different phases present in GEOFS have been investigated further by XRD analysis. Table 2. XRF analysis report of GEOFS XRD Analysis: Fig. 3 demonstrates the XRD diffractograms of GGBS Portland clinker and GEOFS samples. Appeared broad signal of the GGBS sample suggests the amorphous nature of the material. The sharp signals of both the diffractograms of clinker and EOF slag suggest the predominated crystalline nature of both samples. Moreover, there are certain signals appeared in both the diffractograms of EOF slag and clinker (marked with a red dotted arrow in Fig 3). Those common signals [(30.1 °, 32.1 °) and (29.4 °, 34.26 °)] are probably responsible for crystalline phases of dicalcium silicate (denoted by C2, Fig. 3) and tricalcium silicate (denoted by C3, Fig. 3) [8]. Hence it is confirmed that EOF slag contains some cementitious phases as similar to clinker. Figure 1: Digital images of (a) EOF slag, (b) GEOFS, (c) GGBS, (d) OPC, and (e) PSC 3. Figure 2: Optical polarizing microscopy images of (a) GGBS, (b) GEOFS. Grades of blended cement Composition of blended cement (%) OPC [350 M2/Kg] GGBS [345 M2/Kg] GEOFS [350 M2/ Kg] PSC 1 50 50 0 PSC 2 50 47.5 2.5 PSC 3 50 45 5 PSC 4 50 42.5 7.5 PSC 5 50 40 10 Components Content in GEOFS (%) Loss on Ignition 6.262 CaO 31.530 MgO 18.330 SiO2 13.130 Al2O3 4.870 Fe2O3 20.200 MnO 3.480