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Showing 1 to 20 of 45 for “"Alkali silica reaction"”.
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Mitigating alkali silica reaction in recycled concrete
… recycled concrete aggregate (RCA) that had shown alkali silica reaction (ASR) distress was evaluated. It was found that ASR mitigation was needed to prevent continued expansion. Several mitigation methods were evaluated and compared to conventional concrete using the testing procedures of ASTM C …
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The control of alkali silica reaction using blended cements
It has been previously established that alkali silica reaction (ASR) in concrete may be controlled by blending Portland cement with suitable hydraulic or pozzolanic materials. The controlling mechanism has been attributed to the dilution of the cement's alkali content and reduced mobility of ions …
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Alkali Silica Reaction Mitigation Using High Volume Class C Fly Ash
<p>Alkali-Silica Reaction (ASR) is a neutralization reaction that occurs between an acid (silicic acid) and a basic pH pore solution (Calcium Oxide, Potassium Oxide, and Sodium Oxide). ASR causes deleterious expansion within concrete, which can cause durability issues decreasing the life span of …
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Modeling Alkali -Silica Reaction Using Image Analysis and Finite Element Method
The microstructure-based model developed in the present study appears to be unique and promising in spite of some difference because the numerical results are in a good agreement with experimental data. It is considered that image analysis and FEM are powerful tools to understand the overall …
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Effects of Alkali-Silica Reaction on Response of Concrete Squat Shear Walls
Alkali-Aggregate Reaction (AAR) problem is common in structures such as bridges, roadways, airport runways, and nuclear power plants that were built with reactive aggregate. The Alkali-Aggregate Reaction progresses with time in concrete between the alkaline cement paste and reactive amorphous …
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A factorial approach to the study of alkali-silica reaction in concrete
… which investigates certain aspects of the alkali-silica reaction in concrete. A factorial approach was adopted for the experimental stages of the investigation. Such an approach is based on proven statistical techniques and has the advantage of allowing any interaction between the …
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Thermo-chemo-mechanical modelling of hydropower structures affected by alkali silica reaction
Alkali-Silica Reaction (ASR) is a deleterious chemical reaction whose product expands in the presence of water inducing internal pressures within the concrete microstructure resulting in cracking and a reduction in elastic properties of concrete. Thus, ASR can substantially reduce serviceability …
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Characterization, Evaluation, And Repair of Full-Scale Alkali-Silica Reaction Affected Structural Concrete
Alkali–silica reaction (ASR), a chemical reaction occurring in concrete between reactive siliceous minerals in some aggregates and alkalis in the concrete pore solution, can produce an expansive gel that, in the presence of sufficient moisture, leads to expansion and cracking. This not only …
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Investigation on the Overall Performance of Recycled Concrete Affected by Alkali-Silica Reaction
… reactive aggregates in many quarries in Canada, alkali-silica reaction (ASR) is one of the most common deterioration mechanisms. The durability and long-term performance of RCA concrete are not fully understood and should be further investigated, especially in regards to a) the potential of …
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Digital image correlation analysis of alkali silica reaction in concrete with recycled glass aggregate
… inspires the application in studies of concrete alkali silica reaction (ASR). In this study, a MATLAB DIC code is employed as a strain measurement method to enhance the ASTM C1260 Standard Test Method for Potential Alkali Reactivity of Aggregates (Mortar-Bar Method). Recycled glass is used as the …
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Accelerated Alkali-Silica Reaction and Corrosion of Reinforcing Steel in Concrete: Application on Dry Casks
… reinforced concrete structures are corrosion and alkali-silica reaction (ASR). These two processes occur very slowly and to assess them in a short period of time, they need to be accelerated. Furthermore, these mechanisms are dependent on the geometry and boundary conditions of the structure. …
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Effect of calcium-silicon ratio on the expansion of mortar bars due to alkali-silica reaction
<p>In this experiment, mortar bars were prepared with three kinds of industrial solid waste and two kind of aggregates. Positive correlation between expansion induced by ASR and C/S ratio was obtained from the experiment result. Expansion of specimens prepared with standard sand and three …
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Effects of the alkali-silica reaction on unloaded, statically loaded and dynamically loaded reinforced concrete beams.
The Alkali-Silica Reaction (ASR) affects many concrete structures throughout the world. Small scale, simply supported, singly reinforced concrete beams made of both reactive and non-reactive aggregate have been tested. Reactive and non-reactive concrete cylinders, resonant frequency prisms and CSA …
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Mitigation and Evaluation of Alkali-Silica Reaction (ASR) and Freezing and Thawing in Concrete Transportation Structures
<p>An evaluation of alkali-silica reaction (ASR) and freezing and thawing (F/T) in concrete transportation structures is presented along with mitigation methods for slowing the rate of deterioration in concrete. A combination of field and laboratory testing confirms ASR deterioration is exacerbated …
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Biomass and Coal Fly Ash in Concrete: Strength, Durability, Microstructure, Quantitative Kinetics of Pozzolanic Reaction and Alkali Silica Reaction Investigations.
… of traditional (neat) coal fly ash. Pozzolanic reactions occur simultaneously but not necessarily proportionally to strength development. Mixtures of biomass and coal fly ash in all proportions mitigate alkali-silica-reaction-based (ASR-based) expansion in concrete. Biomass-specific results …
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Identifying Damage, Predicting Expansion, and Determining the Effectiveness of Sealers on Concrete Affected by Alkali-Silica Reaction and Freeze-Thaw
… Fayetteville, Arkansas due to a combination of Alkali-Silica Reaction (ASR) and freeze-thaw has led to ASR and freeze-thaw research at the University of Arkansas. Potential for further expansion (PFET), Damage Rating Index (DRI), and mitigation of freeze-thaw and ASR with sealers testing and …
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Finite element model updating of concrete arch dams affected by alkali-silica reaction using ambient vibration monitoring and dam surveillance data
… impacts associated with their collapse. Alkali-Silica Reaction (ASR) is a deleterious chemical reaction that affects the performance and safety of numerous concrete dam structures around the world. To ensure dam safety, a well-structured dam surveillance program that includes ambient …
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Using lithium compounds as an admixture in new concrete and as a post-treatment for existing concrete affected by alkali-silica reaction
… to mitigate or prevent deterioration due to alkali-silica reaction (ASR). The first objective of the project is the assessment of the current test methods available for testing the efficacy of lithium nitrate as an admixture. The two test methods used were ASTM C 1260 and ASTM C 1293 and …
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Characterization and deterioration detection of portland cement concrete using ultrasonic waves
… detect deterioration induced by freeze/thaw and alkali-silica reaction, and to detect chloride presence in PCC using ultrasonic waves. The experimental program was initiated to investigate the effect of water to cement (w/c) ratio, aggregate type, and air entrainn1ent on measured ultrasonic wave …
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