Thermal and sound insulation characteristics of CNT infused ultra-high-strength lightweight concrete (UHSLC)

초록

This study investigates the properties of carbon nanotube (CNT) infused ultra-high-strength lightweight concrete (UHSLC), focusing on its thermal and sound insulation characteristics. Five UHSLC mixtures, with a specific strength higher than 52.2 MPa m3/t, were prepared by incorporating 0.05 wt% CNT and 1 vol% of different types and combinations of fibers (steel and polyethylene). The results indicated that CNT reduced the slump flow diameter due to its large specific surface area, with PE fibers causing a greater reduction in flowability than steel fibers. All UHSLC specimens exhibited densities below 1600 kg/m3, meeting the maximum limit of lightweight concrete (LWC), while steel fibers increased density more significantly than PE fibers. The addition of CNT improved the pore structure, lowering porosity, but the incorporation of fibers increased total and continuous porosity, enhancing sound absorption, particularly in the UC-PE mixture. Mechanical properties showed that CNT and steel fibers significantly increased compressive and tensile strengths, with UC-ST achieving the highest compressive strength and UC-STPE exhibiting optimal strain capacity due to fiber hybridization. Thermal conductivity remained around 0.600 W/m & sdot;K across all UHSLC, benefiting from the utilization of hollow microspheres and the low thermal conductivity of PE fibers. The study concludes that CNT infused UHSLC effectively combines mechanical strength with superior thermal and sound insulation properties, positioning it as a viable material for energy-efficient construction and reduced carbon footprint in the modular construction sector.

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