Cement, Energy and Environment

19 gypsum) have been prepared. To assess the performance of the developed cements all the performance parameters have been analyzed (according to IS: 4031). The tolerance ranges of ground EOF slag (GEOFS) in blended cement have been optimized concerning maximum usage of GEOFS without compromising the compressive strength and other parameters. Finally, the optimized blended cement has been used for concrete trials to evaluate its applicability in concrete. 2.0 MATERIALS AND METHODS 2.1. Material: EOF slag (from JSW Steel Ltd, Salem Works, India), GGBS, and OPC (from JSW Cement Ltd, Vijayanagar Works, India). 2.2.Pre-application processing of EOF Slag The collected EOF slag was gray and with an irregular shape (<10mm). First, the slag sample (20 Kg) was kept in a hot-air oven at 110 °C for 5 h to remove the moisture contained. Then the moisture-free slag sample was crushed using a lab-scale jaw-crusher to make a smaller granule size (< 3 mm). Then the crushed slag sample was passed through a magnetic separator to isolate the metallic iron particles. Finally, the non-magnetic EOF slag was ground finely using a lab-ball mill. The specific surface area of the ground EOF samplewasmaintained at ~350 m2/Kg. This ground EOF slag (GEOFS) was used for further characterizations and applications. 2.3.Preparation of blended cement The collected OPC Cement was composed of clinker (~93 %) andmineral gypsum (7 %). The specific surface area of OPC and GGBS were 350 and 345 M2/ Kg. Different compositions of blended cement were made (50 Kg each) by blending OPC (50 %), GGBS (35-50 %) and GEOFS (0-15 %). Thus the produced blended cements belong to the Portland Slag Cement (PSC) class. The prepared cements were used for different applications and trials, explained later. 2.4. Materials characterization Optical microscopy of GEOFS andGGBSwas performed in an optical polarizing microscope (Make: Leica, Model: DM4P). The image acquisition was performed in transmitted polarized light. The elemental compositions of GEOFS was analyzed by XRF analysis (Instrument: ARL 9900 Series, Thermo Scientific). The XRD analysis of GEOFS, Portland Cement Clinker, and GGBS samples were performed for phase identification and quantification (Instrument: Empyrean 200684, Panalytical). 2.5. 2.5 Evaluation of physical parameters according to Indian standard (IS 4031) 2.6. Different physical parameters were evaluated according to the Indian Standard (IS: 4031). The normal consistency, and setting times were determined as per the procedure mentioned in IS: 4301. The cement paste was cast using proper molds (as per IS: 4031) to evaluate the soundness behavior of cement. After 1 day of curing these casted samples are analyzed for autoclave and Le-Chatelier expansion. Finally, cement-sand mortar was prepared by manual mixing and cast in cubical molds. After demolding the mortar cubes emerged for water curing. The compressive strength was determined by using a Compressive Strength Testing Machine (CTM) after 1, 3, 7, and 28 days of curing. 2.7. Determination of heat of hydration The heat of hydration of prepared samples (PSC 1 to PSC 5) was determined in an isothermal calorimeter (TAM Air, from TA Instrument). 2.5 g of each sample was taken in a glass ampule and followed by the addition of 1 g of water. The ampule was shaken gently for homogeneous mixing. Then the ampule was sealed with a cap and put in the sample chamber of an isothermal calorimeter for measurement of heat flow and total heat liberation. 2.8.Concreteapplication Lab-scale concrete trials of developed blended cement were conducted for M30 design to evaluate the applicability as well as the compressive strength in concrete. After concrete mixing the workability of the concrete was checked followed by concrete cube casting for compressive strength determination after water curing for 3, 7, and 28 days. 3.0 RESULTS AND DISCUSSION 3.1. Pre-application processing of EOF slag and preparation of blended cement The moisture content of collected EOF slag was ~2% (weight %). Then the experiment to separate magnetic content has found ~12% segregated magnetic material. Then the GEOFS was blended with OPC and GGBS to make different compositions of blended cements (PSC 1 to PSC 5). The compositions of these samples have been demonstrated in Table 1. Among the all prepared blended cement grades, PSC 1 has having least GEOFS content (0 %) and PSC 5 has having maximum GEOFS content (10 %). The PSC 1 sample was considered as a control