Reinforcing pore structure and ITZ of foam concrete enabled by DNA self-assembled CNTs networks

In this study, CNTs networks were formed on the foam and quartz sand based on the self-assembly of deoxyribonucleic acid (DNA), which propose two organic-inorganic hybrid materials (CNTs-sand and CNTs-foam) for reinforcing foam concrete. DNA can not only disperse CNTs by π-π stacking but also form ionic-hydrogen bond with KOH modified quartz sand. On the other hand, a three-phase foam stabilized by DNA/CNTs was prepared. The test results of mechanical properties indicated that the compressive, splitting tensile and bending strength are impressively increased by 2 times, 3 times and 2 times compared to control group. CNTs-foam and CNTs-sand did not promote the hydration reaction , according to XRD and TG test results. The enhancement of mechanical properties is predominantly driven by the optimization of pore structure and interfacial transition zone (ITZ), as evidenced by SEM , X-CT and nanoindentation . This paper provides an innovative strategy for CNTs dispersion in foam concrete and contributes to designing high-performance foam concrete.