Cement, Energy and Environment

23 M30 Concrete mix design Material Quantity per M3 (Kg) PSC Cement 440 20 mm Aggregate 641 12.5 mm Aggregate 427 Crushed stone sand 725 Water 185 Results of Concrete Trial Parameter PSC 1 PSC 2 PSC 3 PSC 4 PSC 5 Fresh wet density (Kg/M3) 2403 2412 2418 2420 2423 Workability (Slump Height); Unit: mm Initial 125 135 130 135 130 30 min 100 100 100 95 100 60 min 65 65 70 70 65 Determination of Compressive Strength Curing time Compressive strength (MPa) 72±1 Hrs (3 Days) 17.50 17.86 16.90 18.05 17.15 168±2 Hrs (7 Days) 23.24 25.47 23.73 24.43 23.77 672±4 Hrs (28 Days) 35.47 37.60 36.00 37.27 35.87 Table 4: Details of concrete trial for blended cements. 3.5 Concrete application Concrete is the principal mode of application of cement for civil construction. Concrete provides the structural strength of a building or any civil structure in the form of columns, beams, roof basement, precast blocks, etc. Hence lab lab- scale concrete trial has been performed with the developed blended cements (PSC 1 to PSC 5). The concrete mix design, workability of concrete, fresh wet density, and CS after water curing have been demonstrated in Table 4. It was found that all the developed cement samples (without GEOFS and with GEOFS) showed comparable workability (till 1 h) with gradually decreasing slump height for concrete. This supports the compatibility of GEOFS for concrete applications which provides similar workability with control (PSC 1: Cement without GEOFS). Moreover, an increasing fresh wet density of the concrete mix was found while moving from PSC 1 to PSC5. This can be explained by considering the more replacement of low-density GGBS (Bulk Density: 1.003 g/cc) by high-density GEOFS (1.222 g/cc) in PSC 2 to PSC 5. Compressive strengths of the casted cubes have been demonstrated in Table 4 and Fig. 7. Concrete cubes for all five cement samples demonstrated gradually increasing CS with a progressive time scale (3 days-7 days-28 days). This indicates that the normal cement hydration process with time in all concrete cubes, is in progress. Comparing the trend of CS of the concrete cubes of all five cement samples (PSC 1 to PSC 5), it was observed that 28 days’ CS of PSC 2, 3, and 4 is higher than PSC 1. PSC 5 showed a similar CS to PSC 1. This indicates that the addition of GEOFS shows a