The Experts below are selected from a list of 1089 Experts worldwide ranked by ideXlab platform
Henk M. Jonkers - One of the best experts on this subject based on the ideXlab platform.
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a bacteria based bead for possible self healing Marine Concrete applications
Smart Materials and Structures, 2016Co-Authors: Damian Palin, Virginie Wiktor, Henk M. JonkersAbstract:This work presents a bacteria-based bead for potential self-healing Concrete applications in low-temperature Marine environments. The bead consisting of calcium alginate encapsulated bacterial spores and mineral precursor compounds was assessed for: oxygen consumption, swelling, and its ability to form a biocomposite in a simulative Marine Concrete crack solution (SMCCS) at 8 °C. After six days immersion in the SMCCS the bacteria-based beads formed a calcite crust on their surface and calcite inclusions in their network, resulting in a calcite–alginate biocomposite. Beads swelled by 300% to a maximum diameter of 3 mm, while theoretical calculations estimate that 0.112 g of the beads were able to produce ~1 mm3 of calcite after 14 days immersion; providing the bead with considerable crack healing potential. The bacteria-based bead shows great potential for the development of self-healing Concrete in low-temperature Marine environments, while the formation of a biocomposite healing material represents an exciting avenue for self-healing Concrete research.
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A bacteria-based bead for possible self-healing Marine Concrete applications
Smart Materials and Structures, 2016Co-Authors: Damian Palin, Virginie Wiktor, Henk M. JonkersAbstract:A bacteria-based bead for possible self-healing Marine Concrete applications View the table of contents for this issue, or go to the journal homepage for more 2016 Smart Mater. Struct. 25 084008 Abstract This work presents a bacteria-based bead for potential self-healing Concrete applications in low-temperature Marine environments. The bead consisting of calcium alginate encapsulated bacterial spores and mineral precursor compounds was assessed for: oxygen consumption, swelling, and its ability to form a biocomposite in a simulative Marine Concrete crack solution (SMCCS) at 8 °C. After six days immersion in the SMCCS the bacteria-based beads formed a calcite crust on their surface and calcite inclusions in their network, resulting in a calcite–alginate biocomposite. Beads swelled by 300% to a maximum diameter of 3 mm, while theoretical calculations estimate that 0.112 g of the beads were able to produce ∼1 mm 3 of calcite after 14 days immersion; providing the bead with considerable crack healing potential. The bacteria-based bead shows great potential for the development of self-healing Concrete in low-temperature Marine environments, while the formation of a biocomposite healing material represents an exciting avenue for self-healing Concrete research.
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Bacteria-based agent for self-healing Marine Concrete
Proceedings of the 5th International Conference on Self-Healing Materials, 2015Co-Authors: Damian Palin, Virginie Wiktor, Henk M. JonkersAbstract:Concrete can crack reducing its functional water tightness. If this water contains harmful chemicals such as those found in sea-water deterioration can further ensue until a Concrete structures possible demise. A novel approach to self-healing is a bio-inspired technique, whereby bacteria immobilized in Concrete are able to form a mineral healing precipitate hindering the ingress of aggressive chemicals. Calcium alginate is presented as a method for encapsulating both bacterial spores and magnesium acetate for the production of bio-based self-healing agent. Calcium alginate effectively encapsulated magnesium acetate, leaching the acetate within 24 hours when submerged in pure water. Capsules housed in cement paste expanded by 10 % and only in the first hour. Specific bacteria were able to respire on magnesium acetate and calcium alginate. These results provide key information on the way towards developing bacteria based self-healing Concrete for application in the Marine environment.
Damian Palin - One of the best experts on this subject based on the ideXlab platform.
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a bacteria based bead for possible self healing Marine Concrete applications
Smart Materials and Structures, 2016Co-Authors: Damian Palin, Virginie Wiktor, Henk M. JonkersAbstract:This work presents a bacteria-based bead for potential self-healing Concrete applications in low-temperature Marine environments. The bead consisting of calcium alginate encapsulated bacterial spores and mineral precursor compounds was assessed for: oxygen consumption, swelling, and its ability to form a biocomposite in a simulative Marine Concrete crack solution (SMCCS) at 8 °C. After six days immersion in the SMCCS the bacteria-based beads formed a calcite crust on their surface and calcite inclusions in their network, resulting in a calcite–alginate biocomposite. Beads swelled by 300% to a maximum diameter of 3 mm, while theoretical calculations estimate that 0.112 g of the beads were able to produce ~1 mm3 of calcite after 14 days immersion; providing the bead with considerable crack healing potential. The bacteria-based bead shows great potential for the development of self-healing Concrete in low-temperature Marine environments, while the formation of a biocomposite healing material represents an exciting avenue for self-healing Concrete research.
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A bacteria-based bead for possible self-healing Marine Concrete applications
Smart Materials and Structures, 2016Co-Authors: Damian Palin, Virginie Wiktor, Henk M. JonkersAbstract:A bacteria-based bead for possible self-healing Marine Concrete applications View the table of contents for this issue, or go to the journal homepage for more 2016 Smart Mater. Struct. 25 084008 Abstract This work presents a bacteria-based bead for potential self-healing Concrete applications in low-temperature Marine environments. The bead consisting of calcium alginate encapsulated bacterial spores and mineral precursor compounds was assessed for: oxygen consumption, swelling, and its ability to form a biocomposite in a simulative Marine Concrete crack solution (SMCCS) at 8 °C. After six days immersion in the SMCCS the bacteria-based beads formed a calcite crust on their surface and calcite inclusions in their network, resulting in a calcite–alginate biocomposite. Beads swelled by 300% to a maximum diameter of 3 mm, while theoretical calculations estimate that 0.112 g of the beads were able to produce ∼1 mm 3 of calcite after 14 days immersion; providing the bead with considerable crack healing potential. The bacteria-based bead shows great potential for the development of self-healing Concrete in low-temperature Marine environments, while the formation of a biocomposite healing material represents an exciting avenue for self-healing Concrete research.
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Bacteria-based agent for self-healing Marine Concrete
Proceedings of the 5th International Conference on Self-Healing Materials, 2015Co-Authors: Damian Palin, Virginie Wiktor, Henk M. JonkersAbstract:Concrete can crack reducing its functional water tightness. If this water contains harmful chemicals such as those found in sea-water deterioration can further ensue until a Concrete structures possible demise. A novel approach to self-healing is a bio-inspired technique, whereby bacteria immobilized in Concrete are able to form a mineral healing precipitate hindering the ingress of aggressive chemicals. Calcium alginate is presented as a method for encapsulating both bacterial spores and magnesium acetate for the production of bio-based self-healing agent. Calcium alginate effectively encapsulated magnesium acetate, leaching the acetate within 24 hours when submerged in pure water. Capsules housed in cement paste expanded by 10 % and only in the first hour. Specific bacteria were able to respire on magnesium acetate and calcium alginate. These results provide key information on the way towards developing bacteria based self-healing Concrete for application in the Marine environment.
Cccc Fourth - One of the best experts on this subject based on the ideXlab platform.
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Field Investigation of the Durability of Marine Concrete Structures
China Harbour Engineering, 2020Co-Authors: Fan Zhi-hong, Cccc Fourth, Cccc Shanghai, Cccc Tianjin, Cccc WuhanAbstract:In this paper the site investigations about durability of Marine Concrete structures carried out in North China, East China and South China are described.The damage caused by corrosion of steel bars of the Marine Concrete is analyzed through the appearance survey,and the data of Concrete cover thickness,Concrete strength and reinforcement corrosion potential is obtained by using special detection methods.Such job will provide the basis of durability data for mastering the real durability situation and formulating strategies to develop durability of Marine Concrete structures
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A Study on High Performance Marine Concrete Mixing Technology for Qingdao Bay Bridge
2020Co-Authors: Wang Ying-fei, Cccc FourthAbstract:For the high-salinity and freeze-thaw cycles environment in Jiaozhou Bay,the good-quality mineral admixtures such as fly ash and slag powder,the lower water-binder ratio and highly efficient water reducing agent matched to cementation materials are used to produce high performance Marine Concrete,which could meet the requirement of 100-year service life.The changes of mechanical properties and chlorineion penetration resistance with the age of Concrete are studied.The rapid frozen thaw method and air void spacing factor method are used to analyze and evaluate the freezing resistance of high performance Marine Concrete.The test results show that large number of slag powder and appropriate micro-bubbles could be used to improve the durability of Marine Concrete.
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Variation analysis of cover depth of existing Marine Concrete structures
Port & Waterway Engineering, 2020Co-Authors: Cccc FourthAbstract:The cover-meter testing method is used to measure the cover depths of Marine Concrete structures.A statistical treatment is applied to the cover depth from field inspection for three existing Marine wharves.The results show that the derivation of the testing values is very large,the mean value is very close to the design value,and the testing values of cover depths follow a normal probability distribution function.
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The State of the Art of Durability Monitoring and Its Applications in Marine Concrete Structure
Guangdong Chemical Industry, 2020Co-Authors: Cccc FourthAbstract:The state of the art,technical characteristics,and applications of durability monitoring for Marine Concrete structures were surveyed in the paper.The trend in development of the durability monitoring techniques was forecasted.It would provide references for the development of the durability monitoring technique.
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Durability assessment for Marine Concrete member by grey relational analysis
2020Co-Authors: Cccc FourthAbstract:Two improved grey relational analysis methods,i.e.absolute relational analysis (ARA)and point-slope relational analysis(PSRA), were used to assess the durability of Marine Concrete members based on in-situ tests,in which optimal serials were properly constructed from project-detected durability parameters and Concrete durability grades were decided corresponding to existing codes.The results show that ARA is more preferred for short service-life member with large differentiation;While PSRA,due to taking both similarity and proximity into account,is available to identify the status of Concrete structure member and classify its durability grade.
Zuhua Zhang - One of the best experts on this subject based on the ideXlab platform.
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potential application of geopolymers as protection coatings for Marine Concrete iii field experiment
Applied Clay Science, 2012Co-Authors: Zuhua Zhang, Hao WangAbstract:Abstract Previous studies have shown a high potential of using geopolymers as new inorganic coatings in protecting Marine Concrete. This article reports the results of the experiment on field application. Geopolymer coatings were in-situ applied on the surfaces of Concrete accropodes along the coast. It was observed that the geopolymer coatings set within 4 hours, bound strongly with Concrete and were able to resist the wave shock in the first tide rise. There was a modicum of calcite detected by X-ray diffraction (XRD) but no sulphate was found in the coatings within 6 months. One issue raised during in-situ application is the large shrinkage of the geopolymer paste under ambient condition. Micro-cracks on the surfaces were observed after 7 days although the MgO-based expansion agent and polypropylene (PP) fibers were added to withstand the shrinkage. The humidity of the atmosphere and the thickness of the coating layer are the two significant factors affecting the integrity of coatings. It was noted that the coating with a thickness of 5 mm at the tidal area, where contact with seawater periodically, exhibited the best integrity. To solve the problem of large shrinkage, it is recommended to use suitable aggregates in coating paste and to develop appropriate shrinkage reducing agents together with careful curing procedures.
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potential application of geopolymers as protection coatings for Marine Concrete ii microstructure and anticorrosion mechanism
Applied Clay Science, 2010Co-Authors: Zuhua ZhangAbstract:The excellent anticorrosion property of geopolymers in sea water and their efficient bonding to hardened cement paste did not only depend on the chemical compositions but were also influenced by the microstructure. This study presents an investigation into the interfaces between the geopolymer and cement paste and mortar and the pore structure of geopolymers by scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP) and Brunauer–Emmett–Teller (BET) nitrogen adsorption. The interface between the geopolymer and cement paste was compact and its chemical composition changed due to the reaction between the geopolymer slurry and the surface of cement. Open pores in the geopolymer synthesized with 90% metakaolin (MK) and 10% granulated blast furnace slag (GBFS) were < 15 nm in an average, thus much smaller than the average open pore size in ordinary Portland cement (OPC) paste. The compact microstructure of the geopolymer made it difficult for sea water to penetrate. The amorphous aluminosilicate geopolymeric gels, which were chemically stable in sea water or in air, provided a sustainable protection for Marine Concrete structures.
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potential application of geopolymers as protection coatings for Marine Concrete i basic properties
Applied Clay Science, 2010Co-Authors: Zuhua ZhangAbstract:Abstract Coatings can extend the service life of Concrete structures exposed to Marine environments by inhibiting the intrusion of corrosive ions. In the present paper, the possibility of using geopolymer as an innovative inorganic coating for Marine Concrete protection was evaluated by 5 basic properties: setting time, permeability, anticorrosion and bond strength as well as volume stability. Fresh coat needed about 2 h to finally set at 25 °C. A compound geopolymer was developed by adding 10% granulated blast furnace slag (GBFS) in metakaolin as starting materials at the liquid/solid ratio of 0.60 ml/g. The presence of GBFS had a beneficial effect on reducing the permeability of the geopolymer. Although the strength development was relatively slower under the condition of seawater curing, it convincingly confirmed that geopolymer had excellent anticorrosion property. Furthermore, the average bond strength between geopolymer and cement paste or between geopolymer and mortar was higher than 1.5 MPa, which could be explained by the coexistence of calcium silicate hydrate (C–S–H) gels in cement and geopolymer matrix under strong alkaline condition. In addition, the large shrinkage of the geopolymer was controlled by using polypropylene (PP) fiber and self-prepared MgO expansion agent, later of which could produce a shrinkage compensating effect.
Wang Sheng-nian - One of the best experts on this subject based on the ideXlab platform.
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A Study on Long-term Exposure Test of Marine Concrete
South China Harbour Engineering, 2020Co-Authors: Wang Sheng-nianAbstract:The rules of the chloride ion penetration in Concrete are investigated,based on the long-term exposure test under the ocean environment of South China.The influences of time、water/binder ratio、admixtures upon the durability of Marine Concrete are analyzed.
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Development and current situation for durability technology of Marine Concrete in China
Port & Waterway Engineering, 2020Co-Authors: Wang Sheng-nianAbstract:The corrosive environment and the characteristics of durability damage for Marine Concrete structures are summarized The development process of durability technology from 1980's,the research on the durability technology and its application for Marine Concrete in China are described.Also,the durability technology for Marine Concrete is prospected.
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Research progress on invasion of chloride iron of Marine Concrete structures under alteration of wetting and drying
Port & Waterway Engineering, 2020Co-Authors: Wang Sheng-nianAbstract:The Marine Concrete structures at splash zones or tidal zones are often corroded seriously due to the continual alteration of drying and wetting.The paper mainly introduces the chloride ion transporting mechanism,influence factors and service life prediction model of chloride ingress under the alternation of wetting and drying,which may serve as reference for the durability design of the Marine Concrete located at the area of drying-wetting alteration.
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Research on Theory and Method of Service Life Prediction of Marine Concrete Structures Based on Exposure Test and Filed Investigation
China Harbour Engineering, 2020Co-Authors: Wang Sheng-nian, Cccc FourthAbstract:Some research results of one Western transportation construction project named "Service Life Prediction and Health Monitor of Marine Concrete structures" which is funded by Ministry of Transport are introduced in this paper.In the paper the key parameters of degradation model of Marine Concrete are modified rationally through statistical analysis to data obtained from long-(?)rm exposure test(20 years) and field investigation carried out in typical coastal areas of China,and then the service life prediction model that is suitable for the Marine Concrete of Chinese occasion is established.Through " recovery test" of exposure test,the relationship between indoor test and exposure test for Concrete durability is studied and then the quantitative relation between durability performance and design life of Marine Concrete structures is established.