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Articles 1 - 7 of 7
Full-Text Articles in Engineering
Distribution Of Lithium Nitrite Injected Into Concrete And Its Asr Suppression Effect, Koichi Kobayashi, K Rokugo, Y Takagi, T Otani
Distribution Of Lithium Nitrite Injected Into Concrete And Its Asr Suppression Effect, Koichi Kobayashi, K Rokugo, Y Takagi, T Otani
International Conference on Durability of Concrete Structures
In this research, lithium nitrite was injected into ASR-deteriorated concrete specimens made with reactive aggregates in order to suppress further deterioration. The amount of injected lithium nitrite was set to three different levels, and the subsequent expansion behavior and area of lithium permeation were investigated. The area of permeation was checked using the coloring reagent TDI. It was found that the prescribed amount of lithium cannot be injected fully into the non-deteriorated specimens. When the lithium was injected at an early stage of deterioration, the area of permeation was small and the ASR suppression effect was small regardless of the …
Alkali Reactive Carbonate Rocks: Is It Alkali Silica Reaction (Asr) Or Alkali Carbonate Reaction (Acr)?, Mengesha Beyene, Rc Meininger
Alkali Reactive Carbonate Rocks: Is It Alkali Silica Reaction (Asr) Or Alkali Carbonate Reaction (Acr)?, Mengesha Beyene, Rc Meininger
International Conference on Durability of Concrete Structures
The root cause of distress in two different concrete structures made from carbonate coarse aggregates that fit the textural and compositional criteria cited for ACR was found to be caused by ASR, not ACR. Stereo-optical examination and transmitted polarized light microscopy (PLM) analysis showed that the concretes contain some dark gray, fine-grained argillaceous dolomitic coarse aggregates in which secondary white deposit filling the cracks extending from these aggregates into the paste (as well as lining air voids) is ASR gel. Back scattered electron (BSE) imaging with EDS spectra and x-ray elemental mappings, clearly confirm that the white secondary deposits consist …
Impact Of Portlandite On Alkali-Silica Reaction Of Pyrex Glass And Blastfurnace Slag Aggregate, Natsumi Noguchi, Tomohiro Kajio, Yuka Morinaga, Yogarajah Elakneswaran, T Nawa, Toshiki Ayano
Impact Of Portlandite On Alkali-Silica Reaction Of Pyrex Glass And Blastfurnace Slag Aggregate, Natsumi Noguchi, Tomohiro Kajio, Yuka Morinaga, Yogarajah Elakneswaran, T Nawa, Toshiki Ayano
International Conference on Durability of Concrete Structures
In this study, it is investigated the effect of Ca ion on dissolution and reaction products in alkaline environment using Pyrex glass showing ASR expansion and blast furnace slag fine aggregate suppressing ASR. It is reported that Ca plays a role in the dissolution and polymerization of silica, and is therefore an important factor in ASR. For each sample, calculation of dissolution rate and analysis of solid phase product by 29Si MAS NMR and XRD/Rietveld analysis, and liquid phase analysis by ICP-AES were performed. As a result, it was confirmed that addition of Ca has an influence on dissolution behavior …
Comparison Of Alkali-Silica Chemical Reaction Of Reactive Glass And Chert Aggregate, Yuka Morinaga, Elakneswaran Yogarajah, Toyoharu Nawa, Lalita Yongchaitrakul, Eiji Iwatsuki
Comparison Of Alkali-Silica Chemical Reaction Of Reactive Glass And Chert Aggregate, Yuka Morinaga, Elakneswaran Yogarajah, Toyoharu Nawa, Lalita Yongchaitrakul, Eiji Iwatsuki
International Conference on Durability of Concrete Structures
Alkali silica reaction (ASR) is one of the most important factors of deterioration of Concrete. However, there are a lot of unknown points about ASR such as mechanism of ASR and pessimum effect. We investigate to the mechanism of Alkali silica chemical reaction by using two different aggregates, early type expanded aggregate and delayed type expanded aggregate. Experiments were used to investigate ASR by reaction between reactive silica and alkali ions with or without calcium ions. Two phases of reacted samples (liquid and solid) are presented. In the absence of calcium hydroxide (CH), reactive materials with specified sizes (Yorochert, and …
Investigation Into Mechanisms And Mitigation Of Alkali-Silica Reaction In Sustainable Portland Cement Concrete Containing Recycled Glass Materials, Kaveh Afshinnia
Investigation Into Mechanisms And Mitigation Of Alkali-Silica Reaction In Sustainable Portland Cement Concrete Containing Recycled Glass Materials, Kaveh Afshinnia
All Dissertations
A significant portion of recycled glass from municipal waste streams is not found to be suitable for reuse as cullet in the production of new glass containers, and as a result it is disposed in landfills. One of the appropriate ways to reduce the disposal of waste glass in landfills is by using it in portland cement concrete as an aggregate material and/or supplementary cementitious material to replace portion of portland cement. The high silica content of the soda glass (approximately 70%) can potentially behave as a pozzolanic material when finely ground, which may enhance the mechanical and durability properties …
Alkali Silica Reaction Under The Influence Of Chloride Based Deicers, Purvi Desai
Alkali Silica Reaction Under The Influence Of Chloride Based Deicers, Purvi Desai
All Theses
Highways form the backbone of transportation in United States. As a result, issues related to distress in pavements and use of chemicals on pavement forms one of the major focus areas of highway agencies. One of the forms of distress in concrete pavements is Alkali silica reaction (ASR). External source of alkalis in the form of deicing chemicals play a key role in accelerating ASR. Sodium chloride or Rock salt is one of the oldest forms of deicers. Several research studies have been done on ASR under the influence of sodium chloride and calcium chloride. Limited information is available on …
Assessing Asr Potential Of Hardened Concrete And The Use Of Rice Husk Ash To Mitigate Asr, David Wingard
Assessing Asr Potential Of Hardened Concrete And The Use Of Rice Husk Ash To Mitigate Asr, David Wingard
All Theses
This two part research study was created to first develop a new process using existing test methods to determine the Alkali-Silica Reaction (ASR) potential of hardened concrete that is exposed to external alkalis and secondly to determine the ASR mitigation potential of using rice husk ash (RHA) as a supplementary cementitious material (SCM). The first part of the research study was completed by using a new aggregate extraction procedure that uses a combination of hydrochloric acid treatments and abrasion to remove the cement paste from the aggregate. This extracted aggregate was then crushed down to the specified sizes and used …