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You searched for subject:(autogeneous healing). Showing records 1 – 2 of 2 total matches.

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Delft University of Technology

1. Sangadji, S. Porous Network Concrete: A bio-inspired building component to make concrete structures self-healing.

Degree: 2015, Delft University of Technology

The high energy consumption, its corresponding emission of CO2 and financial losses due to premature failure are the pressing sustainability issues which must be tackled by the concrete infrastructure industry. Enhancement of concrete materials and durability of structures (designing new infrastructures for longer service life) is one solution to overcome the dilemma. Concrete is a quasi-brittle material with properties that are high in compression but weak in tension, therefor concrete is prone to cracking. In the case that a continuous network of cracks is formed, the permeability of concrete will increase and the reinforcement bars may be open to the ambient atmosphere. This opening provides easy means for aggressive substances to enter into concrete and reach rebars which may start to corrode. Further cracks may threaten the tightness of the retaining structures, e.g. liquid containing structures tank wall, aqueducts, underground spaces, tunnels, etc., which undergo tensile forces. In these cases cracks may facilitate the flow of fluid – liquid or gas – into and out of the structures which considerably alters its serviceability, leads to unhealthy environments within a structure, and diminishes its functionality. In case the container or reservoir contains waste, highly toxic materials or radioactive materials, leakage through the concrete is catastrophic and unacceptable. One promising concept to design new concrete structures to achieve higher durability is incorporating self-healing mechanisms that are found in nature into the cement-based materials or the concrete structural element. If unavoidable cracks due to inherent brittleness in concrete could be self-sealed/healed/repaired, concrete will certainly serve longer and be more durable and sustainable. In general, on attempting to solve engineering problems, one can (always) seek inspiration from biology (nature). Though, borrowing nature’s idea to enhance our living environment is as old as humankind, the post-industrial technical advent makes the process more systematic and deliberate, hence makes use of bio-mimicry to solve problems and inspire innovation. Observing the domain of biology, there are several wound healing mechanisms found in nature: cut skin and bone fracture healing in human and animal, and plant response to injury. The present work takes inspiration from studies on bones of present-day mammals and birds and its healing mechanism. Two of appropriate principles that might be constructive are identified; (1) bone morphology comprises of cortical (solid) bone and trabecular (spongious) bone and (2) a feedback loop process is present in the remodelling and healing process. These two principles formed the basis for the development of a healable concrete material and for a method for healing it with healing agents. The idea behind this is that cortical bone may be mimicked with solid concrete and trabecular bone may be imitated by porous concrete. The combination of the two types of concrete resembles Porous Network Concrete, a bone-like… Advisors/Committee Members: Schlangen, E..

Subjects/Keywords: concrete; porous concrete; porous network concrete; self-healing concrete; biomimetic; bio-inspired engineering; closed-loop feedback; autonomous healing mechanism; autogeneous healing mechanism

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Sangadji, S. (2015). Porous Network Concrete: A bio-inspired building component to make concrete structures self-healing. (Doctoral Dissertation). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:b6dcf405-1591-4202-b744-f833cef4541d ; urn:NBN:nl:ui:24-uuid:b6dcf405-1591-4202-b744-f833cef4541d ; urn:NBN:nl:ui:24-uuid:b6dcf405-1591-4202-b744-f833cef4541d ; http://resolver.tudelft.nl/uuid:b6dcf405-1591-4202-b744-f833cef4541d

Chicago Manual of Style (16th Edition):

Sangadji, S. “Porous Network Concrete: A bio-inspired building component to make concrete structures self-healing.” 2015. Doctoral Dissertation, Delft University of Technology. Accessed July 09, 2020. http://resolver.tudelft.nl/uuid:b6dcf405-1591-4202-b744-f833cef4541d ; urn:NBN:nl:ui:24-uuid:b6dcf405-1591-4202-b744-f833cef4541d ; urn:NBN:nl:ui:24-uuid:b6dcf405-1591-4202-b744-f833cef4541d ; http://resolver.tudelft.nl/uuid:b6dcf405-1591-4202-b744-f833cef4541d.

MLA Handbook (7th Edition):

Sangadji, S. “Porous Network Concrete: A bio-inspired building component to make concrete structures self-healing.” 2015. Web. 09 Jul 2020.

Vancouver:

Sangadji S. Porous Network Concrete: A bio-inspired building component to make concrete structures self-healing. [Internet] [Doctoral dissertation]. Delft University of Technology; 2015. [cited 2020 Jul 09]. Available from: http://resolver.tudelft.nl/uuid:b6dcf405-1591-4202-b744-f833cef4541d ; urn:NBN:nl:ui:24-uuid:b6dcf405-1591-4202-b744-f833cef4541d ; urn:NBN:nl:ui:24-uuid:b6dcf405-1591-4202-b744-f833cef4541d ; http://resolver.tudelft.nl/uuid:b6dcf405-1591-4202-b744-f833cef4541d.

Council of Science Editors:

Sangadji S. Porous Network Concrete: A bio-inspired building component to make concrete structures self-healing. [Doctoral Dissertation]. Delft University of Technology; 2015. Available from: http://resolver.tudelft.nl/uuid:b6dcf405-1591-4202-b744-f833cef4541d ; urn:NBN:nl:ui:24-uuid:b6dcf405-1591-4202-b744-f833cef4541d ; urn:NBN:nl:ui:24-uuid:b6dcf405-1591-4202-b744-f833cef4541d ; http://resolver.tudelft.nl/uuid:b6dcf405-1591-4202-b744-f833cef4541d


Delft University of Technology

2. Savija, B. Experimental and numerical investigation of chloride ingress in cracked concrete.

Degree: 2014, Delft University of Technology

Chloride induced corrosion of reinforcing steel is recognized as the most common deterioration mechanism affecting reinforced concrete structures. As such, it has been in focus of research for more than thirty years. Numerous studies of chloride ingress, corrosion initiation, and corrosion propagation have been conducted. Most studies of chloride ingress focused on sound (uncracked) concrete. In reality, however, concrete is almost never crack free. Cracks form either in the construction phase (early age cracks, for example shrinkage cracks), or during the use of a structure (e.g. cracks caused by mechanical loads). While these cracks are usually not detrimental to the load bearing capacity of a structure, they are potentially a threat to its durability. Cracks occurring in the concrete cover diminish its protective capabilities, and present fast routes for ingress of deleterious species (e.g. chloride ions). While national and international design codes provide guidelines and limits for maximum crack widths in aggressive environmental conditions, these are often empirical and based on rules of thumb. As a result, only the surface crack width is considered. However, recent findings seem to indicate that an even more important factor could be the zone of debonding which occurs at the steel/concrete interface due to cracking of the cover. In this thesis, an attempt is made to increase the body of knowledge related to chloride ingress in cracked concrete. Laboratory experiments and numerical simulations were used during the study. Experimental data available in the literature is, at the moment, inconclusive. For years researchers have been trying to find a so-called ''threshold'' crack width for chloride (or water) transport, below which concrete can be treated as sound (uncracked). In this quest, mostly plain concrete specimens were used. While this approach resulted in increased understanding of chloride transport in cracks, it failed to address an important mechanism which affects only reinforced concrete - debonding occurring at the steel/concrete interface. Only recently have researchers focused their attention on the effect of damage at the steel/concrete interface on transport behavior and corrosion of reinforcement in concrete. In this thesis, compact reinforced specimen geometry is adopted, which mimics (with respect to crack geometry) the behavior of reinforced concrete beams. Cracked specimens were subjected to weekly cycles of salt water wetting and drying for a prolonged period of time. After the exposure, two-dimensional chloride maps were obtained by means of LIBS (Laser Induced Breakdown Spectroscopy), in collaboration with BAM Federal Institute for Materials Research and Testing in Berlin, Germany. The results showed that, once damage occurs at the steel/concrete interface, chloride ions penetrate parallel to the reinforcement, which could possibly be very harmful with respect to reinforcement corrosion. It has been frequently reported in the literature that autogeneous healing of cracks can reduce… Advisors/Committee Members: Schlangen, E..

Subjects/Keywords: chloride ingress; autogeneous healing; corrosion induced cover cracking; x-ray computed tomography; nanoindentation; lattice fracture model; lattice transport model

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Savija, B. (2014). Experimental and numerical investigation of chloride ingress in cracked concrete. (Doctoral Dissertation). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:79915ffe-d062-431f-a0ff-bc7628e802be ; urn:NBN:nl:ui:24-uuid:79915ffe-d062-431f-a0ff-bc7628e802be ; urn:NBN:nl:ui:24-uuid:79915ffe-d062-431f-a0ff-bc7628e802be ; http://resolver.tudelft.nl/uuid:79915ffe-d062-431f-a0ff-bc7628e802be

Chicago Manual of Style (16th Edition):

Savija, B. “Experimental and numerical investigation of chloride ingress in cracked concrete.” 2014. Doctoral Dissertation, Delft University of Technology. Accessed July 09, 2020. http://resolver.tudelft.nl/uuid:79915ffe-d062-431f-a0ff-bc7628e802be ; urn:NBN:nl:ui:24-uuid:79915ffe-d062-431f-a0ff-bc7628e802be ; urn:NBN:nl:ui:24-uuid:79915ffe-d062-431f-a0ff-bc7628e802be ; http://resolver.tudelft.nl/uuid:79915ffe-d062-431f-a0ff-bc7628e802be.

MLA Handbook (7th Edition):

Savija, B. “Experimental and numerical investigation of chloride ingress in cracked concrete.” 2014. Web. 09 Jul 2020.

Vancouver:

Savija B. Experimental and numerical investigation of chloride ingress in cracked concrete. [Internet] [Doctoral dissertation]. Delft University of Technology; 2014. [cited 2020 Jul 09]. Available from: http://resolver.tudelft.nl/uuid:79915ffe-d062-431f-a0ff-bc7628e802be ; urn:NBN:nl:ui:24-uuid:79915ffe-d062-431f-a0ff-bc7628e802be ; urn:NBN:nl:ui:24-uuid:79915ffe-d062-431f-a0ff-bc7628e802be ; http://resolver.tudelft.nl/uuid:79915ffe-d062-431f-a0ff-bc7628e802be.

Council of Science Editors:

Savija B. Experimental and numerical investigation of chloride ingress in cracked concrete. [Doctoral Dissertation]. Delft University of Technology; 2014. Available from: http://resolver.tudelft.nl/uuid:79915ffe-d062-431f-a0ff-bc7628e802be ; urn:NBN:nl:ui:24-uuid:79915ffe-d062-431f-a0ff-bc7628e802be ; urn:NBN:nl:ui:24-uuid:79915ffe-d062-431f-a0ff-bc7628e802be ; http://resolver.tudelft.nl/uuid:79915ffe-d062-431f-a0ff-bc7628e802be

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