Effect of Amorphous Metallic Fibers on Thermal and Mechanical Properties of Lightweight Aggregate Cement Mortars Containing Carbon Nanotubes

Lightweight aggregate concrete can reduce the self-weight of a structure with a low unit weight; however, disadvantages such as reduced strength and brittleness remain. This study evaluated the thermal and mechanical properties of lightweight aggregate cement mortars containing carbon nanotubes (CNTs) and amorphous metallic fibers (AMFs). A thermal property test indicated that the peak temperature of the C1A1 and C1A2 samples using AMFs was approximately 91.5–93.8 °C (approximately 57.2–61.1% higher than the C1A0 sample without AMFs). The time to reach the peak temperature was approximately 15–27 min (21.1–38.0% of that for the C1A0 sample). The 28-day split tensile strength of the sample using 20 kg/m3 of the AMFs was approximately 3.6–3.8 MPa (approximately 46.1–50.0% higher than that of CNT-only samples). The 56-day flexural strength of the C2A2 sample using 0.2% CNTs and 20 kg/m3 AMFs was the highest at approximately 11.2 MPa (approximately 24.4% higher than that of the control sample). The results of this study indicate that using CNTs and AMFs can enhance the strength and reduce the brittleness of lightweight aggregate cement mortar. Furthermore, the performance of the cement mortar is significantly improved when combined with AMFs compared to using CNTs alone.