Research on the Improvement of Concrete Autogenous Self-healing Based on the Regulation of Cement Particle Size Distribution (PSD)

Yuan, Liang; Chen, Shuaishuai; Wang, Shoude; Huang, Yongbo; Yang, Qingkuan; Liu, Shuai; Wang, Jinbang; Du, Peng; Cheng, Xin; Zhou, Zhen

doi:10.3390/ma12172818

Cited by 34 publications

(39 citation statements)

References 52 publications

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“…During the research on the self-healing of cement-based composites, when assessing the scale of the changes caused by autogenous self-healing in particular, the change in material properties over time through the progressive hydration of binders [ 14 , 15 , 16 ] should be considered. Figure 1 presents a general diagram of changes in cement-based composite strength during maturation and the restoration of strength during self-healing (at any time point t i of the research) that was lost due to material degradation (at time point t 0 ).…”

Section: Introductionmentioning

confidence: 99%

Self-Sealing Process Evaluation Method Using Ultrasound Technique in Cement Composites with Mineral Additives

2020

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The self-sealing process, associated with chemical and microstructural changes inside damaged cement-based composites, leads to the recovery of the original material integrity. Assessing the magnitude of internal changes in samples using non-destructive techniques to capture only the self-sealing effects is difficult. The challenge is evaluating the differences between subsequent observations in time and between samples with different properties. This paper proposes a new approach to the use of an ultrasonic technique for self-sealing investigation. The method allows the quantification of material changes strictly related to self-sealing processes, excluding changes caused by the naturally progressing hydration of binders. The applied ultrasonic pulse velocity (UPV) data processing procedure allows the investigation of material changes inside and near the cracks, the effects of stimulating the self-sealing of cement composites with mineral additives, and the assessment of changes over time. An important aspect of the method is the sample preparation procedure and testing conditions that reduce the impact of moisture content on the UPV measurements. New parameters allowing the quantitative characterization of the self-sealing process are proposed. The method was evaluated using cement mortars modified with siliceous fly ash with induced cracks 0 to 750 µm wide, which were then cured in water for 152 days. The maximum degree of effective crack filling as a result of autogenous self-sealing in the tested mortars was determined to range from 33% to 57%. Observations of the microstructure of the crack surface confirmed that apart from the volume of the newly formed products, the density of these products may have a key impact on the ultrasonic measurements of the self-sealing performance. The studies were supplemented by the examination of the compression strength of mortars, mortar sample scanning and computer image processing, and observations using an optical microscope and scanning electron microscope with energy dispersive spectroscopy.

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Section: Introductionmentioning

confidence: 99%

Self-Sealing Process Evaluation Method Using Ultrasound Technique in Cement Composites with Mineral Additives

2020

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“…This fine powder involves the risk of inhalation, as all fine binders, during processing and all the necessary measures for protection (such as mask and gloves) should be taken into account during the preparation of the suspension. The exact impact of the nano-particles’ use is not clear due to the lack of available toxicity information [ 36 , 37 ].…”

Section: Discussionmentioning

confidence: 99%

The Influence of Curing Regimes in Self-Healing of Nano-Modified Cement Pastes

2020

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The present study proposes nano-calcium oxide (NC) and nano-silica (NS) particles as healing agents in cement pastes, taking into account the curing conditions. Two series of specimens were treated in water and under wetting-drying cycles. The addition of NC (1.5%wt of binder) triggered early healing since cracks were healed within 14 days in underwater immersion and before 28 days at wetting-drying cycles. Attenuated Total Reflectance (ATR) spectroscopy and SEM analysis revealed that the healing products were mainly aragonite and calcite in water conditions and more amorphous carbonates under wetting-drying cycles. The combination of NS and NC (3.0%wt in total) offered healing under both curing conditions before 28 days. The presence of NS assisted toward porosity refinement and NC increased the carbonates’ content. The newly formed material was dense, and its elemental analysis by SEM revealed the C-S-H compounds that were also verified by ATR.

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“…Securing the long-term durability of marine concrete structures, which are difficult to maintain, is an important issue. One of the ultimate factors affecting the durability of concrete structures is the occurrence of micro-cracks [1][2][3][4][5]. In particular, the infiltration of chloride ions into the micro-cracks could destroy the passive film of rebars embedded in reinforced concrete structures due to electrochemical reactions, thereby causing the corrosion of rebars [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…Crack-closure work, therefore, is fundamental to protect the concrete from deterioration factors and to improve the long-term durability. In general, there is an autogenous healing system of concrete itself; however, its crack healing efficiency depends on environmental factors and the crack width that can be filled is restricted [3,10,11]. As a new concept of self-healing technology, the microbial metabolism-based crack healing mechanism has garnered attention.…”

Section: Introductionmentioning

confidence: 99%

Impact of Bio-Carrier Immobilized with Marine Bacteria on Self-Healing Performance of Cement-Based Materials

et al. 2020

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The present study evaluated the self-healing efficiency and mechanical properties of mortar specimens incorporating a bio-carrier as a self-healing agent. The bio-carrier was produced by immobilizing ureolytic bacteria isolated from seawater in bottom ash, followed by surface coating with cement powder to prevent loss of nutrients during the mixing process. Five types of specimens were prepared with two methods of incorporating bacteria, and were water cured for 28 days. To investigate the healing ratio, the specimens with predefined cracks were treated by applying a wet–dry cycle in three different conditions, i.e., seawater, tap water, and air for 28 days. In addition, a compression test and a mercury intrusion porosimetry analysis of the specimens were performed to evaluate their physico-mechanical properties. The obtained results showed that the specimen incorporating the bio-carrier had higher compressive strength than the specimen incorporating vegetative cells. Furthermore, the highest healing ratio was observed in specimens incorporating the bio-carrier. This phenomenon could be ascribed by the enhanced bacterial viability by the bio-carrier.

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Research on the Improvement of Concrete Autogenous Self-healing Based on the Regulation of Cement Particle Size Distribution (PSD)

Cited by 34 publications

References 52 publications

Self-Sealing Process Evaluation Method Using Ultrasound Technique in Cement Composites with Mineral Additives

Self-Sealing Process Evaluation Method Using Ultrasound Technique in Cement Composites with Mineral Additives

The Influence of Curing Regimes in Self-Healing of Nano-Modified Cement Pastes

Impact of Bio-Carrier Immobilized with Marine Bacteria on Self-Healing Performance of Cement-Based Materials

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