Chloride Penetration at Cold Joints of Structural Members with Dissimilar Concrete Incorporating UHPC

Farzad, Mahsa; Fancy, Saiada Fuadi; Lau, Kingsley; Azizinamini, Atorod

doi:10.3390/infrastructures4020018

Cited by 13 publications

(5 citation statements)

References 15 publications

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“…Other research has been done at Florida International University regarding the chloride penetration, focusing on the effect of corrosion macro cells that can develop between the normal strength concrete (NSC) substrate and the repaired region of the UHPC. Farzad et al [10] states that the repair of concrete elements with UHPC will generally improve the bond strength between two materials, and together with UHPC of low permeability, will result in a more durable structure, improving its service life. This is accomplished by restricting the ingress of damaging agents, improving the sustainability of the repaired structure.…”

Section: System Developmentmentioning

confidence: 99%

Durable Bridge Columns using Stay-In-Place UHPC Shells for Accelerated Bridge Construction

2019

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Ultra-high performance concrete (UHPC) is a durable material that allows the construction of innovative structural elements and conforms with accelerated bridge construction (ABC) goals. The main idea of this research is to utilize UHPC to prefabricate a shell that acts as a stay-in-place form for bridge columns. The prefabricated shell eliminates the conventional formwork while reducing the on-site construction time and acting as a durable protective layer for the normal concrete inside the shell against environmental attacks. In addition, the UHPC shell provides additional confinement to the column concrete, which improves the column's structural performance. During construction and after completing the column reinforcement work onsite, based on the conventional construction methods, the prefabricated UHPC shell is placed around the column reinforcement, followed by casting a portion of UHPC for a column-to-footing connection, which improves the capacity of the connection and shifts the plastic hinge zone above the connection. Once the UHPC portion hardens, normal concrete is placed inside the shell, forming a permanent concrete-filled UHPC shell. The construction process is finalized by placing and connecting a prefabricated cap beam to the column through the same developed connection as that in this research. This technical note presents the development of two test specimens using an UHPC shell in lieu of a conventional formwork with the advantage of improving the column performance and durability.

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Section: System Developmentmentioning

confidence: 99%

Durable Bridge Columns using Stay-In-Place UHPC Shells for Accelerated Bridge Construction

2019

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“…Reinforced concrete structural components of offshore structures are exposed to corrosion due to the impact of salts and require an analysis of durability indicators to obtain more accurate predictions of the occurrence of corrosion and its course [29]. At the same time, when studying the durability of reinforced concrete, it is important to take into account the effect of chlorides on the corrosion of steel and welds [30,31], taking into account the properties of concrete [31]. There are quite a few studies devoted to the numerical simulation of the transport and diffusion of chlorides in concrete and reinforced concrete elements under cyclic exposure [32,33].…”

Section: Introductionmentioning

confidence: 99%

The Influence of Recipe-Technological Factors on the Resistance to Chloride Attack of Variotropic and Conventional Concrete

et al. 2023

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A current problem in the construction industry is the lack of complex, scientifically based technological materials and design solutions for universal types of building materials, products, and structures, especially in terms of structures operating under conditions of aggressive chloride exposure. The aim of the study was to compare and evaluate the differences in the durability of conventional and variotropic concretes made using three different technologies, vibrating, centrifuging, and vibro-centrifuging, modified with the addition of microsilica, under conditions of cyclic chloride attack. Laboratory experiments and analyses using scanning electron microscopy were conducted. Vibro-centrifuged concrete showed the highest resistance to cyclic aggressive chloride exposure, which was expressed by a lower percentage drop in compressive strength compared to vibrated (87%) and centrifuged concrete (24%). The use of a microsilica as a modifying additive in the amount of 2–6%, instead of as a part of the binder, had a positive effect on the resistance of concrete to cyclic chloride attack. The most effective intervention was the introduction of additives in the amount of 4%. There was a reduction in the loss of strength of vibrated, centrifuged, and vibro-centrifuged concrete after 90 “dry-wet” cycles, as a result of the use of a modifying additive, in an amount between 45% and 55%, depending on the type of technology being used for producing a composite. The combined effect of the use of vibro-centrifuged concrete and microsilica led to a 188% decrease in strength loss resulting from cyclic chloride exposure.

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“…Despite the established desired characteristics of existing commercial repair mortars, the redundancy of their application i.e., the need to re-repair systems has been identified as the reason for high costs. Furthermore, corrosion has also been observed as the commonly reported mortar and concrete deterioration in highways and the pavement industry with repair mortars in place [1,2]. Furthermore, a study revealed that about 20% of the in-place repair mortars have failed within their early periods i.e., 5 years indicating pre-mature damage [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Self-Waterproofing Performance of Repair Mortars With Inorganic Healing Agents

2023

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In Europe, about 55% of concrete bridges are about 50 years old and require non-structural rapid repair strategies to reinstate the aesthetic and durability performances. Existing strategies focus primarily on superficial restoration that continues to demonstrate premature deterioration due to inevitable micro-crack formations that further propagate to macro-cracks leading to the ingress of moisture along with harmful ions. In this study, the benefits of self-healing technology to control moisture ingress at the microscale were investigated. For this, tailored microcapsule with inorganic healing agent, specifically, commercially available water-repellent agent (SIKAGARD 705L) was added to mortar with two types of commonly used binders namely CEMI 52.5N and CEMI 52.5R. The compatibility assessment in terms of capsule integration, fresh and hardened properties was done. The baseline healing efficiency of the mortars without any healing additions was obtained to understand the autogenous healing capacity of the reference mortars. Subsequently, the reference mortar mixes were compared with mixes containing varying fractions of microcapsules (3, 5, and 10%) for autonomous healing efficiency with capillary absorption as the main durability function. The healing efficiency was further investigated for two different crack mouth widths (<250 μm and >350 μm); representative of non-structural residual crack widths. In mortars with microcapsules, a maximum reduction of sorptivity coefficients up to 82% and 78% with CEMI 52.5N and CEMI 52.5R mortars, respectively, for specimens cracked after 7 days of curing was observed. Subsequently, a synergetic effect of autogenous healing action and autonomous water-repellent action for durability recovery was identified and proved useful for repair mortar applications. The healing agent investigated, capsule content, and healing environment considered in the current study lay a foundation for further optimisation to improve the performance and to suit different applications.

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Chloride Penetration at Cold Joints of Structural Members with Dissimilar Concrete Incorporating UHPC

Cited by 13 publications

References 15 publications

Durable Bridge Columns using Stay-In-Place UHPC Shells for Accelerated Bridge Construction

Durable Bridge Columns using Stay-In-Place UHPC Shells for Accelerated Bridge Construction

The Influence of Recipe-Technological Factors on the Resistance to Chloride Attack of Variotropic and Conventional Concrete

Self-Waterproofing Performance of Repair Mortars With Inorganic Healing Agents

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