Self‐healing of engineered cementitious composites under reversed and sustained loading conditions

Abstract

The present study investigates the effects of reversed and sustained flexural loading cycles on the repeatability of self‐healing in engineered cementitious composites (ECC). The experimental work is designed to test three cases of normal (REF), reverse (REV), and reverse‐sustained (RES) loading and three different exposure conditions of tap water, sea water, and open air. A total of 27 prism specimens (100 × 100 × 350 mm) were fabricated, and a four‐point bending test was used for flexural load application at different stages and to further measure the recovery in mechanical properties. The research is proposed to elaborate on the positive/negative impact of compression cycle on the self‐healing of cracks. Ultrasonic pulse velocity (UPV) test was carried out before and after each loading and the wave travel time was compared as an indicator of healing efficiency. To monitor crack propagation patterns and crack widths, digital image correlation (DIC) technique was used. To further analyze the mineralogy and microstructure of the healing products, X‐ray diffraction (XRD) test was conducted on two groups of tap water and sea water exposures. Concluding results proved that sea water and tap water are suitable environments for autogenous self‐healing process. Furthermore, reverse loading cycles were demonstrated to impact the self‐healing results and should be considered for repeatable self‐healing evaluations.

Innovative Strategies for Enhanced Concrete Durability: A Comparative Analysis of Autogenous and Autonomous Self-healing Mechanisms

“…The same findings were noted by (De Belie et al 2018) when reviewing the different self-healing technologies. Thus, the concrete crack age is essential for healing because it confirms visual inspection results that early-age cracked samples heal larger cracks than late-age ones (Mahmoodi et al, 2019).…”

“…14 show that the earlyage cracked samples have better healing ability than the lateage samples in all mixtures. These results can be explained by the hypothesis that the ability of the unhydrated cement particles to continue hydration is higher in young-age concrete (Mahmoodi et al, 2019;Neville 2002).…”

A Bibliometric Analysis of the Studies on Self-Healing Concrete Published between 1974 and 2021

“…Approaches and techniques used to achieve self-healing in concrete can be categorized into two groups, autogenous and autonomous self-healing. Autogenous self-healing of concrete is a phenomenon where cracks are sealed due to the reaction of unhydrated cement particles with moisture in the air, resulting in crystalline materials forming [8][9][10]. Indeed, this method has great potential but has some drawbacks.…”

Effect of different exposure conditions on the self‐healing capacity of engineered cementitious composites with crystalline admixture

“…[17][18][19][20] However, the formation of healing products is dependent on the properties of the surrounding environment such as presence of moisture, pH, temperature, and ion concentration. 12,[21][22][23][24] In particular, seawater exposure has reported promising results of autogenous self-healing in cementitious materials. Although the extend of healed cracks in the presence of the moisture ranges from 50 to 150 μm, the healed crack width for seawater exposure is ranging between 200 and 700 μm.…”

“…These characteristics of ECC have made it a candidate for improving the autogenous self‐healing mechanism 17–20 . However, the formation of healing products is dependent on the properties of the surrounding environment such as presence of moisture, pH, temperature, and ion concentration 12,21–24 . In particular, seawater exposure has reported promising results of autogenous self‐healing in cementitious materials.…”