Performance optimization of ultra-lightweight foamed concrete using dimethicone-infused organosilicon compound.

The study investigated the solid-phase modification of ultralightweight foamed concrete (ULFC) cementitious composites using dimethicone compound at five different concentrations (0.5%, 1.0%, 1.5%, 2.0%, and 2.5% by weight). This research focused on studying the characteristics of dimethicone-based ULFC, including its fresh, mechanical, pore structure, and thermal properties. In this study, we examined the characteristics of fresh concrete, such as the time it takes to set initially and finally (Si, Sf), its workability, and its wet density. The transport characteristics, such as the sorptivity coefficient (S), water absorption (Wa), intrinsic permeability (IP), and rapid chloride permeability (RCP), underwent testing. The mechanical characteristics examined included compressive strength (fc), splitting tensile strength (ft), flexural strength (ff), modulus of elasticity (E), and dry shrinkage (Sh). The measurements of dry density and oven (D), porosity, dispersion, scanning electron microscopy (SEM), pore organization, thermal conductivity (K), and diffusivity (α) were conducted. The results indicated that by increasing the foam to a density of 49.4 kg/m³, it was possible to generate ULFC with a dry density of 450 kg/m³. Incorporating 0.5–2.5% dimethicone into ULFC mixes enhanced the properties of fresh, transport, mechanical, pore organization, and dry density, while raising the thermal conductivity and diffusion by 22% and 9.8%, respectively. The incorporation of 2% dimethicone into ULFC blends enhanced the workability and initial and final setting time by 8%, 61%, and 28% and reduced both the dry and oven-dried density by 1.3% and 1.25%, respectively. Its inclusion resulted in a 27% improvement in S, a 17.7% improvement in Wa%, a 22.5% improvement in IP, and a 30% improvement in RCP as transport characterizations at 28 days of age. The inclusion of this material significantly enhanced the mechanical properties of the control mix, which improved fc, ft, ff, E, and Sh by 182%, 237%, 200%, 207%, and 48%, respectively, at 28 days. The inclusion of a 2% additive resulted in a pore arrangement improvement that was almost comparable to that of a 2.5% additive. The 2% additive enhanced the porosity, small capillary pores, and average particle size by 8%, 18%, and 46%, respectively, after 28 days. These results were consistent with the SEM results. Dimethicone can be used successfully to improve the water resistance and mechanical properties of ULFC.