Investigation of hydration kinetics, microstructure and mechanical properties of multiwalled carbon nano tubes (MWCNT) based future emerging ecological economic ultra high-performance concrete (E3 UHPC)

Abstract

In recent years, attest to the growing prominence of sustainable buildings and the integration of advanced materials like nanomaterials in construction practices. Among these advancements, the strategic application of multi-walled carbon nanotubes (MWCNTs) alongside dispersion techniques such as surfactant agents, functionalization, and ultrasonication is pioneering. These techniques are instrumental in elevating the mechanical strength and durability of cement paste and mortar. The approach involves gradually introducing nanomaterials to create a cementitious composite, allowing for a systematic analysis of their effects on each type and determination of the optimal dosage. The influence of MWCNT with various dosage combination on rheological, mechanical and microstructural properties of ultra high-performance concrete (UHPC) were investigated in this study. According to test results, the UHPC MWCNT 0.06 % mix can be considered as the best UHPC mix due to discussed specifications. The outcomes of the research demonstrate that the optimal dosage of MWCNT enhances various mechanical properties of UHPC significantly. At 28 days of curing, the addition of MWCNT resulted in improvements of 32.97 % in compressive strength, 49.72 % in split tensile strength, 40.41 % in flexural strength, and 9.09 % in dynamic modulus. The observed enhancements in mechanical properties can be attributed to the pore-filling, bridging, and densification effects of MWCNT within the calcium-silicate-hydrate structure of UHPC. Moreover, the incorporation of MWCNT facilitates the development of a more sustainable and environmentally friendly UHPC, thereby supporting sustainable construction practices.