Self-healing performance of aged cementitious composites

Yıldırım, Gürkan; Khiavi, Arash Hamidzadeh; Yeşilmen, Seda; Şahmaran, Mustafa

doi:10.1016/j.cemconcomp.2018.01.004

Cited by 120 publications

(39 citation statements)

References 32 publications

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“…As the building blocks in cementitious materials are consumed over time due to ongoing hydration, the material may behave differently upon loading and healing at different ages. In literature, a recent study showed that autogenous healing is still present in 1-year old specimens (Yıldırım et al, 2018). However, in this research, specimens with an age up to 8 years are studied.…”

Section: Introductionmentioning

confidence: 94%

Autogenous Healing in Strain-Hardening Cementitious Materials With and Without Superabsorbent Polymers: An 8-Year Study

Snoeck

Belie

2019

Front. Mater.

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To obtain a more sustainable concrete, occurring cracks should be repaired. However, as manual repair is time-consuming and expensive, self-healing may provide a proper solution. Autogenous healing is an already a present feature in cementitious materials, but it is an inferior mechanism as it can only completely heal cracks up to 30 µm in the presence of water. Therefore, a cementitious material with synthetic microfibers to limit the crack widths and superabsorbent polymers (SAPs) to provide the necessary water was proposed. However, due to ongoing hydration, autogenous healing based on further hydration of unhydrated cement may be less efficient in time. In this study, the ability of autogenous healing in time (on specimens with an age of 7 days, 28 days, 3 months, 1 year, 3 years, and 8 years) is investigated by comparing the mechanical characteristics after performing four-point-bending tests. The specimens were first loaded to 1% strain at their respective age, stored in a specific healing condition (a relative humidity of 60%, more than 90% and wet/dry cycles) for 28 days and were subsequently reloaded. The results show that, with increasing age, the mean crack width decreases. All specimens can partially heal and regain some of the mechanical properties after being preloaded and re-cracked under four-point-bending. If SAPs are added, there is partial healing in an environment without liquid water (more than 90% RH). At an early age, the healing is governed by further hydration and calcium carbonate crystallization. From 3 months onwards, the main autogenous healing mechanism is calcium carbonate crystallization. Overall, mixtures with SAPs generally showed more self-healing and are thus a promising material to be used in future building applications.

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Section: Introductionmentioning

confidence: 94%

Autogenous Healing in Strain-Hardening Cementitious Materials With and Without Superabsorbent Polymers: An 8-Year Study

Snoeck

Belie

2019

Front. Mater.

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“…According to Clear, to achieve an increased self‐healing efficiency, crack widths should be less than 300 μm level. Moreover, it was concluded very recently that cracks almost as wide as half a millimeter (458 μm) could easily be closed by autogenous self‐healing mechanism as long as proper further environmental conditioning is applied for an adequate duration (30 days) even when specimens are relatively old (1‐year‐old) . It can be stated based on these findings from the literature that there is a very high likelihood for individual restrained shrinkage cracks of ring specimens produced with HPFRC mixtures to be closed and/or minimized easily in width especially at early ages to be harmless in accordance with the allowable crack widths presented in Figure which may serve well for increased serviceability of structures utilizing such mixtures.…”

Section: Resultsmentioning

confidence: 96%

Dimensional stability of deflection‐hardening hybrid fiber reinforced concretes with coarse aggregate: Suppressing restrained shrinkage cracking

Yıldırım

2018

Structural Concrete

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High Performance Fiber Reinforced Concretes (HPFRCs) with deflection‐hardening capability are relatively novel materials with high damage tolerance. However, mixture proportions of such materials are mostly designed with fine aggregates for easier/homogenous fiber distribution and low matrix fracture toughness which increases the amount of cementitious materials as the main binder and related risk for dimensional instability, high cost, and environmental unfriendliness. Here, with the idea of developing concrete that is free of shrinkage‐related cracking at a more reasonable price, deflection‐hardening HPFRC mixtures incorporating different amounts of coarse aggregates (with maximum size of 12 mm) were developed with different mixture parameters (fiber types/dosages and fly ash contents) and tested for their dimensional stability by focusing mainly on the drying and restrained shrinkage measurements. Experimental results reveal that the combined effectiveness of utilizing hybrid fiber reinforcement and high amounts of coarse aggregates by properly adjusting the matrix properties without compromising high ductility (deflection‐hardening behavior) can help the realization of possible producibility of HPFRC mixtures that are completely free of restrained shrinkage‐related cracking. The findings of this study are believed to make a significant impact on the wide‐spread usage of deflection‐hardening HPFRC mixtures with similar ingredients to that of conventional concrete in actual field conditions.

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“…Although some researchers have already concluded that crack will be self-healed with the width less than 50 μm (Yıldırım et al 2018;Zhu et al 2012Zhu et al , 2016, the crack will worsen with interaction of freeze-thaw cycle and carbonation in the study. Hydration reaction for un-hydrated cement particle, carbonation effect for carbon dioxide and pozzolanic reaction for fly ash exist during the interaction process of Eco-HDCC.…”

Section: Crack Trendmentioning

confidence: 81%

“…Considerable efforts have been made regarding the self-healing performance of HDCC in relation to various crack width. If the crack width was less than 100 μm, self-healing rate of HDCC exposed in water for 90 days can reach 80%, while self-healing rate of HDCC exposed in CO 2 -air conditions may reach 40% (Yıldırım et al 2018). Studies also concluded that crack self-healing performance of HDCC subjected to freeze-thaw cycle was obvious with a crack width of less than 43 μm (Zhu et al 2012(Zhu et al , 2016.…”

Section: Introductionmentioning

confidence: 99%

Flexural Behaviors of Ecological High Ductility Cementitious Composites Subjected to Interaction of Freeze-Thaw Cycles and Carbonation

Chai

Guo

Chen

et al. 2019

ACT

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To explore flexural behaviors of ecological high ductility cementitious composites (Eco-HDCC) for bridge deck link slab under severe service conditions, interaction experimental schemes of freeze-thaw cycles and carbonation were designed. Factors such as interaction cycle and preloading stress level were considered. Carbonation front and pore structure of Eco-HDCC were analyzed. The results show that ultimate flexural strength and ultimate deflection of Eco-HDCC decrease when interaction cycle or preloading stress level increases. Besides, all flexural load-deflection curves exhibit four stages: linear elastic, non-linear, deflection hardening and deflection softening stage. In addition, carbonation front of Eco-HDCC increases when interaction cycle or preloading stress level increases. With the same depth range in Eco-HDCC, pore structure deteriorates as interaction cycle increases, and deterioration degree of pores decreases as depth increases. For general consideration, after interaction cycles of 15, flexural property of Eco-HDCC with preloading stress level of 0.5 can be adopted for bridge deck link slab design with the aim to safety.

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Self-healing performance of aged cementitious composites

Cited by 120 publications

References 32 publications

Autogenous Healing in Strain-Hardening Cementitious Materials With and Without Superabsorbent Polymers: An 8-Year Study

Autogenous Healing in Strain-Hardening Cementitious Materials With and Without Superabsorbent Polymers: An 8-Year Study

Dimensional stability of deflection‐hardening hybrid fiber reinforced concretes with coarse aggregate: Suppressing restrained shrinkage cracking

Flexural Behaviors of Ecological High Ductility Cementitious Composites Subjected to Interaction of Freeze-Thaw Cycles and Carbonation

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