scholarly journals Self-Healing Concrete Using Rubber Particles to Immobilize Bacterial Spores

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2313 ◽  
Author(s):  
Hongyin Xu ◽  
Jijian Lian ◽  
Maomao Gao ◽  
Dengfeng Fu ◽  
Yue Yan
Keyword(s):  
Particle Size ◽  
Construction Material ◽  
Plain Concrete ◽  
The Self ◽  
Bacterial Spores ◽  
Self Healing ◽  
Strength Tests ◽  
Rubber Particles ◽  
Practical Engineering ◽  
Rubber Concrete

Bacteria-based self-healing concrete is a construction material used to repair cracks in concrete, in which the bacterial spores are immobilized by bacteria carriers. However, the currently available bacteria carriers are not always suitable due to a complicated procedure or high cost. To develop a more suitable bacteria carrier as well as improve the anti-crack capability of self-healing concrete, in this study we evaluate the feasibility of using rubber particles as a novel bacteria carrier in self-healing concrete. Two types of self-healing concrete are prepared with rubber particles of different sizes to quantify the crack-healing effect. In addition, the fluidity and mechanical properties of the self-healing rubber concrete are compared with those of plain concrete and normal rubber concrete. The experimental results show that the self-healing rubber concrete with a particle size of 1~3 mm has a better healing capacity than the self-healing rubber concrete with a particle size of 0.2~0.4 mm, and the width value of the completely healed crack is 0.86 mm. The self-healing rubber concrete has a higher slump than the plain concrete and normal rubber concrete. According to the strength tests, the compressive strengths of the self-healing rubber concrete are low early on but they exceed those of the corresponding normal rubber concrete at 28 days. Moreover, the self-healing rubber concrete has higher splitting tensile strengths than the plain concrete and a better anti-crack capability. The results of a comparison to the other two representative bacterial carriers indicate that rubber particles have potential to be a widely used bacteria carrier for practical engineering applications in self-healing concrete.

scholarly journals Transformation of Construction Cement to a Self-Healing Hybrid Binder

2019 ◽  
Vol 20 (12) ◽  
pp. 2948 ◽  
Author(s):  
Werner E.G. Müller ◽  
Emad Tolba ◽  
Shunfeng Wang ◽  
Qiang Li ◽  
Meik Neufurth ◽  
...  
Keyword(s):  
Soil Bacteria ◽  
Construction Material ◽  
Water Soluble ◽  
The Self ◽  
Average Chain Length ◽  
Self Healing ◽  
Cement Concrete ◽  
Low Concentrations ◽  
Natural Mechanism ◽  
Long Chain

A new biomimetic strategy to im prove the self-healing properties of Portland cement is presented that is based on the application of the biogenic inorganic polymer polyphosphate (polyP), which is used as a cement admixture. The data show that synthetic linear polyp, with an average chain length of 40, as well as natural long-chain polyP isolated from soil bacteria, has the ability to support self-healing of this construction material. Furthermore, polyP, used as a water-soluble Na-salt, is subject to Na+/Ca2+ exchange by the Ca2+ from the cement, resulting in the formation of a water-rich coacervate when added to the cement surface, especially to the surface of bacteria-containing cement/concrete samples. The addition of polyP in low concentrations (<1% on weight basis for the solids) not only accelerated the hardening of cement/concrete but also the healing of microcracks present in the material. The results suggest that long-chain polyP is a promising additive that increases the self-healing capacity of cement by mimicking a bacteria-mediated natural mechanism.

Application of bacterial spores coated by a green inorganic cementitious material for the self-healing of concrete cracks

2020 ◽  
Vol 113 ◽  
pp. 103718 ◽  
Author(s):  
Mingyue Wu ◽  
Xiangming Hu ◽  
Qian Zhang ◽  
Weimin Cheng ◽  
Di Xue ◽  
...  
Keyword(s):  
Cementitious Material ◽  
The Self ◽  
Bacterial Spores ◽  
Self Healing

Influence of Cement Coarse Particle on the Self-Healing Ability of Concrete Based on Ultrasonic Method

2010 ◽  
Vol 177 ◽  
pp. 526-529 ◽  
Author(s):  
Zhi Qiang Li ◽  
Zong Hui Zhou ◽  
Dong Yu Xu ◽  
Jing Hua Yu
Keyword(s):  
Particle Size ◽  
Wave Amplitude ◽  
Ultrasonic Method ◽  
The Self ◽  
Experimental Results ◽  
Coarse Particle ◽  
Head Wave ◽  
Self Healing ◽  
Before And After ◽  
The Relationship

The influences of particle size and mixing content of coarse cement on the self-healing ability of concrete were researched by ultrasonic method. Damaged degree was measured through the decrease of ultrasonic head wave amplitude (UHA) before and after loading. The relationship between damaged degree and self-healing ratio of concrete was built based on the experimental results as well as the relationship between cement diameter and self-healing ratio of concrete. Analyzing results show that UHA can evaluate the damaged degree of concrete clearly. There exists a damaged threshold of the concrete during loading. Under the same mixing content of coarse cement, when the damaged degree is higher than the threshold, the self-healing ratio of concrete decreases with the increase of damaged degree and increases with the increase of coarse cement diameter, however, while the damaged degree is less than the threshold, the self-healing ratio of concrete increases with both the increase of damaged degree and coarse cement diameter.

Mechanical and Microstructure Study of the Self Healing Bacterial Concrete

2019 ◽  
Vol 969 ◽  
pp. 472-477
Author(s):  
Sachin Tiwari ◽  
Shilpa Pal ◽  
Rekha Puria ◽  
Vikrant Nain ◽  
Rajendra Prasad Pathak
Keyword(s):  
Compressive Strength ◽  
Bacillus Megaterium ◽  
Construction Material ◽  
Research Work ◽  
Bacillus Sphaericus ◽  
Maximum Amount ◽  
The Self ◽  
Self Healing ◽  
Scanning Electron ◽  
Bacterial Concrete

Concrete largely used for construction material, degrades with the development of cracks that becomes easy passage for entry of chemicals and harmful compounds. Self healing capability is helpful to mitigate the deterioration of the concrete structures. This research work focuses on the self healing behaviour and mechanical properties of the bioconcrete supplemented with three different bacteria namely Bacillus sphaericus, Bacillus cohnii and Bacillus megaterium. Concrete supplemented with Bacillus cohnii exhibited 35.31% increase in compressive strength compared to control mix after 28 days. Concrete supplemented with other bacteria Bacillus sphaericus and Bacillus megaterium also showed enhanced compressive strength. Interestingly, addition of bacteria aided in healing of artificially generated cracks by formation of CaCO3 minerals. Maximum amount of healing (bacterial precipitation) which could be quantified as calcite minerals present in the bacterial concrete was 11.44% with B. cohnii confirmed by the Scanning Electron Microscope (SEM) with Energy Dispersive Spectroscopy (EDS).

scholarly journals Preparation and Properties of Self-Healing Waterborne Polyurethane Based on Dynamic Disulfide Bond

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2936
Author(s):  
Gongbo Ye ◽  
Tao Jiang
Keyword(s):  
Particle Size ◽  
Tensile Strength ◽  
Healing Process ◽  
Waterborne Polyurethane ◽  
The Self ◽  
Polymer Materials ◽  
Self Healing ◽  
Heat Treated ◽  
Healing Efficiency ◽  
Excellent Stability

A self-healing waterborne polyurethane (WPU) materials containing dynamic disulfide (SS) bond was prepared by introducing SS bond into polymer materials. The zeta potential revealed that all the synthesized WPU emulsions displayed excellent stability, and the particle size of them was about 100 nm. The characteristic peaks of N-H and S-S in urethane were verified by FTIR, and the chemical environment of all elements were confirmed by the XPS test. Furthermore, the tensile strength, self-healing process and self-healing efficiency of the materials were quantitatively evaluated by tensile measurements. The results showed that the self-healing efficiency could reach 96.14% when the sample was heat treated at 70 °C for 4 h. In addition, the material also showed a good reprocessing performance, and the tensile strength of the reprocessed film was 3.39 MPa.

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

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2818 ◽  
Author(s):  
Lianwang Yuan ◽  
Shuaishuai Chen ◽  
Shoude Wang ◽  
Yongbo Huang ◽  
Qingkuan Yang ◽  
...  
Keyword(s):  
Particle Size ◽  
Portland Cement ◽  
Ultrasonic Test ◽  
The Self ◽  
Internal Crack ◽  
Cement Particle ◽  
Hydrated Cement ◽  
Self Healing ◽  
Optical Micrograph ◽  
Suitable Amount

Overgrinding of Portland cement brings excessive shrinkage and poor self-healing ability to concrete. In this paper, through the ultrasonic test and optical micrograph observation, the self-healing properties of concrete prepared by cement with different particle size distributions were studied. Besides, the effect of carbonation and continued hydration on self-healing of concrete was analyzed. Results show that, for the Portland cement containing more particles with the size 30~60 μm, the concrete could achieve a better self-healing ability of concrete at 28 days. For the two methods to characterize the self-healing properties of concrete, the ultrasonic test is more accurate in characterizing the self-healing of internal crack than optical micrograph observation. The autogenous self-healing of concrete is jointly affected by the continued hydration and carbonation. At 7 days and 30 days, the autogenous self-healing of concrete is mainly controlled by the continued hydration and carbonation, respectively. The cement particle size could affect the continued hydration by affecting un-hydrated cement content and the carbonation by affecting the Ca(OH)2 content. Therefore, a proper distribution of cement particle size, which brings a suitable amount of Ca(OH)2 and un-hydrated cement, could improve the self-healing ability of concrete.

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