Implementación de nanomateriales como material cementicio suplementario (SCM) en el desarrollo de hormigones de ultra alta resistencia (UHPC)

Abstract

The present work includes the results obtained after the incorporation of Nanosilica (NS) at 1%, 2% and 3%, as well as Carbon Nanotubes (CNT) at 0.05%, 0.25% and 0.45% to a Master Sample (MM) referred as Ultra-High Performance Concrete (UHPC). Nationally produced materials were implemented except for the NS and CNT, which were imported. 389 cubic samples of 50 mm edge and 71 cylinders of 10 x 20 were made. Mixing times varied between 16 and 20 minutes. Two curing regimes were tested, 18 ° C and 60 ° C (for the first 48 hours) and growth curves were established generally between 3 and 56 days, depending on the curing method. Lastly, resistance to simple compression, splitting tensile strength, modulus of elasticity and pulse velocity were studied. A decrease in workability and an increase in density is reflected as the higher the percentage of incorporation of the nanomaterial. The best results (in both curing regimes) were obtained with the addition of 2% NS and 0.25% CNT; There is an improvement with respect to MM of between 8% and 12% in compression and traction testing, and a slight improvement in its elasticity modulus. The CNT-0.25% were established as the best addition according to cost/benefit, however, they increase by 31% in the carbon footprint and 14% in the energy demand according to the Life Cycle Analysis (LCA) studied. The potential of the inclusion of CNT through a correct dispersion method could further improve the properties, induce a nanoscale reinforcement, dispersing uniformly in the matrix, creating more bridges for a rapid formation of hydration products with the combination of the nucleation effect. Further studies are encouraged to achieve a balance in the emissions caused by industrialized CNT production and promote its use in the market.