The thermal and mechanical properties of concrete in which normal weight aggregate has been substituted with lightweight aggregates were investigated. The properties were found to be dependent on the volume fraction of the lightweight aggregate, as well as on the nature and quality of the aggregate. The addition of lightweight aggregates resulted in a decreased thermal conductivity, as well as a decreased thermal diffusivity in all samples. The compressive strength ...
Ambient pressure dried hydrophobic silica aerogel monoliths were prepared via simultaneous solvent exchange and surface modification in order to minimize volume shrinkage and density. At room temperature, the obtained silica aerogels had a low density of 0.096 g/cm³, a high surface area and hydrophobicity, and a low thermal conductivity of 0.0217 W/m·K. The effect of heating on these properties was also determined. After the aerogel had been heated to 300°...
A porous matrix was prepared using low-density sawdust and a metakaolin-based geopolymer paste. The matrix was prepared in order to evaluate its performance as a thermally insulating building envelope. The matrices that had approximately 4 MPa of bi-axial four points flexural strength were prepared in a ratio of geopolymer paste:sawdust of between 1:1 and 1:1.5, and the thermal conductivity of these matrices was between 0.2-0.3 W/m·K....
A variety of tannin-formaldehyde aerogels were produced in order to examine the effects of pH and dilution during their manufacture. The authors produced a phase diagram that could describe them. Extensive physical property characterization was performed on the sample aerogels, including porosity, thermal conductivity, volume shrinkage, BET surface area and microscopic texture. Conditions under which the highest surface area and pore volumes were produced were identified. The TPS instrument was ...
This article discusses the creation of a porous mullite ceramic through the incorporation of fly ash cenospheres (FAC) into mullite powder through the gelcasting process. Sintering temperature and the amount of FAC added were investigated as factors affecting density and strength. The authors found that the porous mullite ceramics had a high strength, and high porosity (48.1-72.2%) Thermal conductivity was measured and was determined to be 0.16-0.22 W/mK....
