Preparation and performance of graphene oxide/self-healing microcapsule composite mortar

Author(s):  
Liang Tang ◽  
Zhihe Cheng ◽  
Xianzhang Ling ◽  
Shengyi Cong ◽  
Jiaming Nan

Abstract To meet the unique requirements for concrete durability and resistance in power transmission projects in Northwest China. Microcapsules were created physically using sodium silicate and bentonite as the capsule core and ethyl cellulose as the capsule wall. By using graphene oxide as a conductive medium, standard specimens of cement-based materials were created. Indoor experiments and micro technology were used to determine the optimal ratio of graphene-microcapsules, study the effects of graphene content, microcapsule content, and curing age on compressive strength, resistance, and self-repairing effect of the composite material. The average microcapsule size was 1.25 mm, according to the findings. The microcapsule was a relatively regular sphere with a rough surface and dense structure. The recommended content was 2% microcapsules and 0.1% graphene oxide. The compressive strength first increased and then decreased as the number of microcapsules and graphene oxide increased, and the resistance gradually increased. The repairing rate of compressive strength was 57% after the cracks were repaired, and the recovery rate was 81%.

2020 ◽  
Vol 990 ◽  
pp. 8-12
Author(s):  
Sasan Farhadi ◽  
Shervin Ziadloo

The cracks naturally exist in concrete and make it weak to the deleterious environment, ending with structure degradation. According to this fact, concrete requires to be improved and remediated. Self-healing methods are considered as a helpful way to mitigate the propagation and development of the cracks in the concrete. Bio-mineralization methods can heal the concrete by using bacteria suchlike Bacillus subtilis and Bacillus pasteurii, which can seal the cracks by CaCO3 precipitation. The literature represents the MICP method of using bacteria in concrete, which can improve the concrete durability by increasing the compressive strength. Furthermore, the different kinds of bacteria used in the concrete structure and the methods of employing as a self-healing agent review. Moreover, it illustrates B. Pasteurii and B. Sphaericus has more efficient results between other bacteria due to increasing the compressive strength and lifespan of the concrete.


2021 ◽  
pp. 51371
Author(s):  
Yulong Wang ◽  
Yaqiong Li ◽  
Maoyong He ◽  
Jingjing Bai ◽  
Bingxiao Liu ◽  
...  

Author(s):  
Kui Xu ◽  
Ming Zhang ◽  
Jie Liu ◽  
Nan Sha ◽  
Wei Xie ◽  
...  

Abstract In this paper, we design the simultaneous wireless information and power transfer (SWIPT) protocol for massive multi-input multi-output (mMIMO) system with non-linear energy-harvesting (EH) terminals. In this system, the base station (BS) serves a set of uplink fixed half-duplex (HD) terminals with non-linear energy harvester. Considering the non-linearity of practical energy-harvesting circuits, we adopt the realistic non-linear EH model rather than the idealistic linear EH model. The proposed SWIPT protocol can be divided into two phases. The first phase is designed for terminals EH and downlink training. A beam domain energy beamforming method is employed for the wireless power transmission. In the second phase, the BS forms the two-layer receive beamformers for the reception of signals transmitted by terminals. In order to improve the spectral efficiency (SE) of the system, the BS transmit power- and time-switching ratios are optimized. Simulation results show the superiority of the proposed beam-domain SWIPT protocol on SE performance compared with the conventional mMIMO SWIPT protocols.


2019 ◽  
Vol 129 ◽  
pp. 285-291 ◽  
Author(s):  
Jing Li ◽  
Zhenwei Li ◽  
Qingkang Feng ◽  
Hanxun Qiu ◽  
Guangzhi Yang ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4139
Author(s):  
Yanju Wang ◽  
Zhiyang Lin ◽  
Can Tang ◽  
Wenfeng Hao

The amounts of the components in a microcapsule self-healing system significantly impact the basic performance and self-healing performance of concrete. In this paper, an orthogonal experimental design is used to investigate the healing performance of microcapsule self-healing concrete under different pre-damage loads. The strength recovery performance and sound speed recovery performance under extensive damage are analyzed. The optimum factor combination of the microcapsule self-healing concrete is obtained. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) are carried out on the concrete samples before and after healing to determine the healing mechanism. The results show that the healing effect of self-healing concrete decreases with an increase in the pre-damage load, and the sound speed recovery rate increases with an increase in the damage degree. The influence of the sodium silicate content on the compressive strength and compressive strength recovery rate of the self-healing concrete increases, followed by a decrease. The optimum combination of factors of the microcapsule self-healing system is 3% microcapsules, 30% sodium silicate, and 15% sodium fluosilicate. The results can be used for the design and preparation of self-healing concrete.


2015 ◽  
Vol 3 (33) ◽  
pp. 17445-17458 ◽  
Author(s):  
Wei Cui ◽  
Jin Ji ◽  
Yi-Feng Cai ◽  
Hang Li ◽  
Rong Ran

Illustration of a self-healing, anti-fatigue GHA gel being applied as a recyclable adsorbent for dye wastewater treatment.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Wei Wang ◽  
Shuo Liu ◽  
Qizhi Wang ◽  
Wei Yuan ◽  
Mingzhang Chen ◽  
...  

Based on forced vibration tests for high-performance concrete (HPC), the influence of bridge vibration induced by traveling vehicle on compressive strength and durability of HPC has been studied. It is concluded that 1 d and 2 d compressive strength of HPC decreased significantly, and the maximum reduction rate is 9.1%, while 28 d compressive strength of HPC had a slight lower with a 3% maximal drop under the action of two simple harmonic vibrations with 2 Hz, 3 mm amplitude, and 4 Hz, 3 mm amplitude. Moreover, the vibration had a slight effect on the compressive strength of HPC when the simple harmonic vibration had 4 Hz and 1 mm amplitude; it is indicated that the amplitude exerts a more prominent influence on the earlier compressive strength with the comparison of the frequency. In addition, the impact of simple harmonic vibration on durability of HPC can be ignored; this shows the self-healing function of concrete resulting from later hydration reaction. Thus, the research achievements mentioned above can contribute to learning the laws by which bridge vibration affects the properties of concrete and provide technical support for the design and construction of the bridge deck pavement maintenance.


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