Development of ultralightweight foamed concrete modified with silicone dioxide (SiO2) nanoparticles: Appraisal of transport, mechanical, thermal, and microstructural properties

Over the last few decades, researchers have devoted significant consideration to the use of nanoscale elements in concrete. Silicone dioxide nanoparticles (SDNs) have been a popular subject of study among the several types of nanoparticles. This article describes the findings of a laboratory study that examines the properties of ultra lightweight foamed concrete (ULFC) including different proportions of SDNs. Wide range of properties were evaluated specifically slump flow, density, consistency, flexural strength, modulus of elasticity, compressive strength, split tensile strength, thermal properties, porosity, water absorption, sorptivity, intrinsic air permeability and chloride diffusion. Additionally, scanning electron microscope (SEM) analysis and pore distributions of different mixes were determined and analyzed. Results confirm a noticeable increase in ULFC mechanical properties, with respective improvements in 28-day compressive, split tensile, and flexural strengths of up to 70.49 %, 76.19 %, and 51.51 % at a 1.5 % SDNs inclusion. However, further increases in the SDNs percentage did not result in remarkable enhancements. As the SDN percentage increased from 1.5 % to 2.5 %, the ULFC's sorptivity, porosity, water absorption, intrinsic air permeability, and chloride diffusion all showed substantial improvements. When compared to the control sample, ULFC with SDNs showed higher thermal conductivity values. The reason for this occurrence was determined to be the smaller pore size observed in ULFC specimens containing SDNs. A great adjustment in the distribution of pore diameters was observed in ULFC mixes when the percentages of SDNs were adjusted. The ULFC specimens, which included SDNs at percentages of 0.5 %, 1.0 %, and 1.5 %, showed a reduction in the total number of large voids measuring 500 nm or more, compared to the control ULFC specimen. The findings of this study highlight the potential benefits of incorporating SDNs into ULFC, which may improve its overall properties.