Mechanical Recovery of Cracked Fiber-Reinforced Mortar Incorporating Crystalline Admixture, Expansive Agent, and Geomaterial

Abstract

This research is sought to characterize the stimulated autogenous healing of fiber-reinforced mortars that incorporate healing agents such as crystalline admixtures, expansive agents, and geomaterials. The effects of the healing materials on mechanical performance and water permeability were evaluated experimentally. Furthermore, microscopic and microstructural observations were conducted to investigate the characteristics and physical appearance of healing products within healed cracks. Test results are presented herein regarding index of strength recovery (ISR), index of damage recovery (IDR) and index of dissipation energy gain (IDEG) in relation to crack healing, and reduction of water flow rate. The self-healing capability of the mortars was greater in terms of resisting water flow rather than recovering mechanical performance likely because water flow depends on surface crack sealing, whereas mechanical performance depends on bonding capacity as well as full-depth healing of cracks; thus, mechanical performance may further be improved after longer healing duration.

Calcium hydroxide influence in autogenous self-healing of cement-based materials in various environmental conditions

“…Therefore, the further anhydrous cement grains´ hydration and the calcium hydroxide carbonation are the main mechanisms for its development. In the autonomous self-healing, different methodologies can promote the cracks healing or sealing, such as: crystalline admixtures (ARNDT, 2019;BORG et al, 2018;CUENCA;TEJEDOR;FERRARA, 2018;ROIG-FLORES et al, 2015), superabsorbent polymers (SILVA, 2018; SNOECK; PEL; DE BELIE, 2020), microorganisms (DA SILVA et al, 2015;; ERŞAN et al, 2018;GONZÁLEZ et al, 2020), vascular networks (MINNEBO et al, 2017SELVARAJOO et al, 2020), and fibers (BULLER et al, 2019;MORETTI, 2016;NISHIWAKI et al, 2012;ZHANG;MA, 2014). Lastly, the repair is called the external action produced in the finished matrix to promote the crack healing, for example, crystalline admixture as a surface treatment (CAPPELLESSO, 2016), and microorganism compounds (DE MUYNCK;VERSTRAETE, 2009).…”

Stimulated autogenous-healing capacity of fiber-reinforced mortar incorporating healing agents for recovery against fracture and mechanical properties

“…To prepare HA1, Na 2 CO 3 was dissolved in water, zeolite was added to the mix, and the mixture was dried at 40 • C for 24 h and then immediately dried at 100 • C for 72 h. Powdered healing agents passed through a 0.06 mm sieve were obtained by sieving and crushing HA1 composed of such a mix and stearate. HA2 comprised HA1 powder, calcium sulfoaluminate (CSA) as an expansion agent, and bentonite as a geomaterial in the proportions of 3:2:1 [10].…”

“…where P is the maximum load attained by the specimen, L is the support length during 3-PBT (300 mm), b is the width of the prism (100 mm), d is the prism depth (100 mm), and a is the notch depth (40 mm) [10]. After obtaining the stress values, the area under the curve (W o ) for all mix type specimens was obtained and the required fracture energy was calculated by the following Eq.…”

“…Ferrara et al [9] investigated the effect of crystalline admixture on the self-healing behavior of concrete by evaluating mechanical performance in terms of index of load recovery (ILR) and index of damage recovery (IDR). Another work was conducted by Buller et al [10] and they investigated the mechanical performance of FRC mortar using special selfhealing agents at an early age of healing duration. This study investigated the IDR, index of stress recovery (ISR), and index of dissipation energy gain (IDEG) at 28 days and 56 days of healing duration and found that due to the use of self-healing agents, narrower cracks attained better recovery (50%) in terms of IDEG at 56 days of healing duration.…”

A Review on Cementitious Self-Healing and the Potential of Phase-Field Methods for Modeling Crack-Closing and Fracture Recovery

“…Commonly used are sulfoaluminate based expansive additives (C-S-A) [ 78 ]. The geo-material-based additives consist of silicon dioxide, sodium aluminum silicate hydroxide, and bentonite clay, which have the capacity to swell [ 79 , 97 , 98 ]. When this type of geo-material is exposed to water, its volume may increase 15–18 times its initial dry volume [ 79 ].…”