Title : Mathematical modelling and ANOVA investigation of lightweight concrete incorporated with ultra-fine stone sludge
The presented study provides a modified mix design to create cellular foamed concrete (CFC) utilising low-grade dolomitic marble slurry (MS), a hazardous micro-fine in-situ stone sludge waste, in place of fine river sand (FRS) and tap water. The Box-Behnken design (BBD) of the response surface approach was used for optimization. The effects of three effective variable parameters, namely the temperature of the water to be added into the foaming agent solution (Tw), the flow value (FV), and the percentage replacement level of MS (per cent Rms), on the four responses, namely the oven-dry density (ODD), the compressive strength at 28 days (fc.28d), the strength performance factor at 28 days (PFc.28d), and the thermal conductivity (k-value), were statistically analysed. To create the blend with the desired hardness and functional qualities, ANOVA and multi-objective optimization were used. The range of the ODD, fc.28d, and k-values for CFC were 985 kg/m3 to 1268 kg/m3, 3.89 MPa to 4.94 MPa, and 0.34 to 0.44 W/m.K, respectively. To study how MS interacts with the CFC microstructure and cement paste matrix, advanced characterisation techniques, including field emission scanning electron microscopy (FE-SEM) and 3D morphological analysis, were also used. The ODD, compressive strength (CS), and k-value of the final optimized mix were 1046 kg/m3, 4.19 MPa, and 0.372 W/mK, respectively when mixed with about 60.0 wt per cent MS.
Keywords: Stone wastes utilization, Lightweight concretes, Thermal Performance, Statistical modelling, Multi-attribute optimization