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Full-Text Articles in Engineering
Evaluation Of Reducing Cement Content In Ndor Class R Combined Aggregate Gradations, Miras Mamirov, Jiong Hu, Yong-Rak Kim
Evaluation Of Reducing Cement Content In Ndor Class R Combined Aggregate Gradations, Miras Mamirov, Jiong Hu, Yong-Rak Kim
Nebraska Department of Transportation: Research Reports
The main objective of this research project was to achieve a cement reduction on Nebraska slip-form pavement concrete through aggregate particle packing optimization. A literature review was conducted to examine different aggregate optimization tools, quality control tests, and historical data of Nebraska Department of Transportation (NDOT) pavement mixtures. It was found that the Modified Toufar Model has good potential in optimizing particle packing and predicting packing degrees. The combined aggregate void content test was found to be useful to experimentally justify optimized aggregate gradations. The Box Test with a modified index and image analysis tool for surface void estimation was …
Influence Of Mineralogical Nature Of Aggregates On Acid Resistance Of Mortar, K P. Ramaswamy, Manu Santhanam
Influence Of Mineralogical Nature Of Aggregates On Acid Resistance Of Mortar, K P. Ramaswamy, Manu Santhanam
International Conference on Durability of Concrete Structures
Cement-based materials being alkaline in nature are often subjected to rapid deterioration on exposure to the aggressive acidic environments. Acids penetrate into the cement matrix causing calcium leaching and deterioration of phases leading to alteration in the microstructure. Currently, there are hardly any codes or standards available for evaluating the durability of materials to acid attack. Moreover, the literature addressing the material resistance is quite inconclusive. This paper aims to evaluate the influence of mineralogical nature of aggregates on the degradation kinetics of cement mortar when exposed to inorganic and organic acid solutions by performing a static accelerated leaching test. …
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 …
Analytical Models For 3-D Diffusion Of Ions From Salt-Contaminated Aggregates, Robert J. Thomas, Andrew D. Sorensen, Marc Maguire
Analytical Models For 3-D Diffusion Of Ions From Salt-Contaminated Aggregates, Robert J. Thomas, Andrew D. Sorensen, Marc Maguire
Civil and Environmental Engineering Faculty Publications
This article presents an analytical investigation of the mobility of salts from contaminated aggregates in concrete. Salt-contaminated aggregates may have varied effects on the mechanical properties and durability of concrete. These depend primarily on the mobility of salts within the concrete matrix. Existing diffusion-based models for the mobility of salts in concrete focus on their intrusion from external sources (e.g., chloride penetration from deicing salts and brines). Such problems are well described by the closed-form solution of Fick’s law for diffusion in one dimension from a continuous source. Salt-contaminated aggregates represent a case of diffusion from a finite internal source …
Using Of Proper Pavement Material For The Intersections With Slow-Moving Traffic, Bekim Selimi
Using Of Proper Pavement Material For The Intersections With Slow-Moving Traffic, Bekim Selimi
International Journal of Business and Technology
Use of proper pavement material for some of intersections need special attention by road designers. At Camp Bondsteel-Kosovo on 2002 were built four road intersections using the concrete as pavement material. Heavy and slow-moving trucks that are turning or accelerating exposed these intersections to some of the highest stress level. After some years this intresections start deteriorating on their surface due to friction. The concrete pavements did not survive this period of usage and after eight years were removed and replaced with asphalt pavements. After more than seven years, the asphalt has shown minor distress but is still in good …