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 ◽  
...  
Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 380 ◽  
Author(s):  
Gerlinde Lefever ◽  
Didier Snoeck ◽  
Dimitrios G. Aggelis ◽  
Nele De Belie ◽  
Sandra Van Vlierberghe ◽  
...  

Addition of superabsorbent polymers (SAPs) to cementitious mixtures promotes the self-healing ability of the material. When cracking occurs; SAPs present inside the crack will swell upon contact with water and subsequently release this water to stimulate the further hydration of unhydrated cement particles and the calcium carbonate crystallization. However; the inclusion of SAPs affects the mechanical performance of the cementitious material by the creation of macro-pores as water is retracted from the swollen SAP. To counteract the reduction in strength, part of the cement is replaced by nanosilica. In this research, different mixtures containing either SAPs or nanosilica and a combination of both were made. The samples were subjected to wet–dry cycles simulating external conditions, and the self-healing efficiency was evaluated by means of the evolution in crack width, by optical measurements, and a water permeability test. In samples containing SAPs, an immediate sealing effect was observed and visual crack closure was noticed. The smaller influence on the mechanical properties and the good healing characteristics in mixtures containing both nanosilica and SAPs are promising as a future material for use in building applications.


2021 ◽  
Vol 907 (1) ◽  
pp. 012006
Author(s):  
S A Susanto ◽  
D Hardjito ◽  
A Antoni

Abstract Concrete is a well-known versatile material, and its application is very common in most structures. Concrete performance is high in compression but low in tensile strength, this leads to the appearance of microcracks when the structure bears the designed loading. Such microcracks when ignored, leaves the structure vulnerable to attacks such as seepage of water, chlorides, and other materials that lead to a reduction in performance, and extreme cases failure of the structure. Since cracking is inevitable in concrete, new materials with self-healing properties are introduced into the mixture to take advantage of the external materials while making the concrete stronger. This type of concrete is widely researched from 1970 until the present day and is still in ‘proof of concept stages, and very few to no applications of autonomous self-healing concrete in real-world structures. This paper is an attempt to further classify the existing methodologies and find the gaps between researchers. The autonomous healing of concrete in present-day research varies in results; this means that the self-healing methodology requires standardization. Furthermore, self-healing in concrete does not mean maintenance is not required, it implies an easier maintenance method is possible due to the benefits gained through a possibly higher early cost in construction.


Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2313 ◽  
Author(s):  
Hongyin Xu ◽  
Jijian Lian ◽  
Maomao Gao ◽  
Dengfeng Fu ◽  
Yue Yan

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.


AIP Advances ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 075018
Author(s):  
Xi Wang ◽  
Hao Qiao ◽  
Ziwei Zhang ◽  
Shiying Tang ◽  
Shengjun Liu ◽  
...  

2021 ◽  
Vol 11 (2) ◽  
pp. 700
Author(s):  
Irene A. Kanellopoulou ◽  
Ioannis A. Kartsonakis ◽  
Costas A. Charitidis

Cementitious structures have prevailed worldwide and are expected to exhibit further growth in the future. Nevertheless, cement cracking is an issue that needs to be addressed in order to enhance structure durability and sustainability especially when exposed to aggressive environments. The purpose of this work was to examine the impact of the Superabsorbent Polymers (SAPs) incorporation into cementitious composite materials (mortars) with respect to their structure (hybrid structure consisting of organic core—inorganic shell) and evaluate the microstructure and self-healing properties of the obtained mortars. The applied SAPs were tailored to maintain their functionality in the cementitious environment. Control and mortar/SAPs specimens with two different SAPs concentrations (1 and 2% bwoc) were molded and their mechanical properties were determined according to EN 196-1, while their microstructure and self-healing behavior were evaluated via microCT. Compressive strength, a key property for mortars, which often degrades with SAPs incorporation, in this work, practically remained intact for all specimens. This is coherent with the porosity reduction and the narrower range of pore size distribution for the mortar/SAPs specimens as determined via microCT. Moreover, the self-healing behavior of mortar-SAPs specimens was enhanced up to 60% compared to control specimens. Conclusively, the overall SAPs functionality in cementitious-based materials was optimized.


Sign in / Sign up

Export Citation Format

Share Document