PSI - Issue 70

M. Vignesh et al. / Procedia Structural Integrity 70 (2025) 650–657

652

Waste foundry exhaust sand (WFS) is a byproduct from foundry industry produced during the manufacturing of green sand mould that has a combination of sand, bentonite, and charcoal (Siddique & Singh, 2011). WFS particles had specific gravity of 2.18, bulk density of 1215 kg/m 3 and fineness modulus of 3.66. 2.6. Waste marble powder Waste marble powder arises from processing of these marble stones for various purposes. WMP used in this work possessed CaCO 3 , MgCO 3 contents at 54% and 45% respectively. Itsdensity ranged about 0.85 gm/cc.

2.7. Mix Proportion

The materials were mixed in the proportion as shown in Table 4. Lime and WMP replaced cement and gypsum. M-sand was replaced by WFS. Water to binder (Lime, WMP and FC) ratio (w/b) was tried from 0.1 to 0.3. Proper consistency of mix was obtained at (w/b) of 0.3. Figure 1 depicts the ingredients used for making the samples

a.) Lime

b.) CDW

d.) Flyash

e.) WMP

c.)WFS

Fig 1. Ingredients for specimens

3. Experimental methods 3.1. Strength Activity Index (SAI)

SAI was conducted as per code provisions of ASTM C311. The control specimen was prepared using 1350 g of sand, 450 g of cement and 225 ml of water. For test samples 20% of cement is replaced by CDW for the first sample and by WFS for the second. SAI values at 7 and 28 days are calculated as per equation (1) SAI = ℎ ℎ ×100 (1) 3.2. Compressive strength The ingredients were first mixed roughly and water was added as per the required consistency while mixing. The prepared mix is then placed in 70×70×70mm mould in 3 layers, each being compacted 25 times. The specimens were demou lded after 24 hours and placed in an hot air oven at a temperature of 60 ⁰C for 24 hours. A part of the cast specimens have been shown in Figure 2.a The specimens were taken out and they were allowed to cool at room temperature and tested for compressive strength as per BIS (IS 3495 Part 1 : 2002) shown in Figure 2.b.

Fig 2. a) Cast samples b) Compressive strength testing of samples