Evaluation of the Self-healing Capability of Ultra-High-Performance Fiber-Reinforced Concrete with Nano-Particles and Crystalline Admixtures by Means of Permeability

Abstract

Self-healing is the capability of a material to repair its damage autonomously. Ultra-High-Performance Fiber Reinforced Concrete (UHPFRC) has potentially higher self-healing properties than conventional concrete because of its lower water/binder content and controlled microcracking due to the high fiber content. This work uses a novel methodology based on the permeability to evaluate autogenous selfhealing of UHPFRC and enhanced self-healing, incorporating several additions. To this purpose, one UHPFRC was selected and modified to include alumina nanofibers in 0.25% by the cement weight, nanocellulose (nanocrystals and nanofibers), in a dosage of 0.15% by the cement weight, and 0.8-1.6% of a crystalline admixture. The results obtained show that the methodology proposed allows the evaluation of the self-healing capability of different families of concrete mixes that suffered a similar level of damage using permeability tests adapted to the specific properties of UHPFRC.

Suspended Multifunctional Nanocellulose as Additive for Mortars

“…The first literature works in the field were mostly about the addition of microcellulose [ 7 , 8 , 9 ]; the exclusive use of NC is more recent [ 10 , 11 , 12 ], as a result of extensive efforts in reducing clogging due to flocculation issues. Indeed, NC demonstrated potential in modifying both fresh and hardened properties of concrete and mortars, from the reduction of bleeding and segregation phenomena [ 13 ], to enhanced cement paste curing and, more generally speaking, strengthening effects [ 14 , 15 ] and to self-healing [ 16 ]. Moreover, Guo et al summarized the effects of cellulose nanocrystals (CNC), cellulose nanofibrils (CNF), bacterial cellulose (BC), and cellulose filaments (CF) not only on the mechanical resistance of cementitious materials, but also on their fresh properties, such as rheology, shrinkage, hydration, as well as their durability [ 17 ].…”

Numerical Modelling of UHPFRC: from the Material to the Structural Element

“…This is not the case of UHPFRC with SH constitutive behaviour and high grade of homogeneity in its properties. Therefore, for UHPFRC with SS is necessary to take into account the durability by means of very well cast and poured concrete and maybe the use of particular additions related to self-healing and improvement of concrete matrix microstructure durability properties (Doostkami et al 2020;Ferrara et al 2016Ferrara et al , 2017Ferrara et al , 2018Kim et al 2019;Negrini et al 2019;Roig Flores 2018;Serna et al 2019;Wang et al 2014).…”