The effect of multi-walled carbon nanotubes on mechanical properties and water adsorption of lightweight foamed concrete

The paper investigates the impact of carbon nanotube-based modifiers on the performance characteristics of lightweight foamed concrete (LFC). The method involves saturating quartz sand with a solution containing a catalyst for carbon nanotube (CNT) growth, followed by the subsequent chemical vapor deposition (CVD) synthesis of CNTs. Evaluation of nanomodified sand samples was conducted using SEM and TEM, thermogravimetry, Raman spectroscopy, and XRD. Compression and flexural strength tests of (LFC) specimens indicated that the optimal proportion of nanomodified sand introduced is 1% by weight with a particle size of 0.16 mm. This resulted in a notable 35% increase in compressive strength and an approximately 32% improved in flexural strength. Furthermore, the modified sample with CNT-based sand exhibited a 27% reduction in water absorption. The paper also presents a potential mechanism to explain the impact of carbon nanotube-based modified sand on the evolving structure of (LFC).