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- Title
- Use of hybrid Rice Husk Ash-Fly Ash mixtures as sustainable supplementary materials for concrete in the marine environment.
- Creator
- Arboleda, Diana., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
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This paper presents the comparison of shrinkage and corrosion characteristics of optimized hybrid Rice Husk Ash (RHA)/Fly Ash (FA)-modified Concrete, with those of normal concrete in the marine environment. Uses of both FA and RHA have numerous environmental benefits. Shrinkage performance was determined by subjecting the mixes to restrained shrinkage testing per ASTM C1581. The time to cracking of the specimens improved an average of 18% with the hybrid mixes. Corrosion testing of reinforced...
Show moreThis paper presents the comparison of shrinkage and corrosion characteristics of optimized hybrid Rice Husk Ash (RHA)/Fly Ash (FA)-modified Concrete, with those of normal concrete in the marine environment. Uses of both FA and RHA have numerous environmental benefits. Shrinkage performance was determined by subjecting the mixes to restrained shrinkage testing per ASTM C1581. The time to cracking of the specimens improved an average of 18% with the hybrid mixes. Corrosion testing of reinforced columns was performed in a simulated tidal cycle Marine Environment. Corrosion potential improved by as much as 35% for the mix with the highest FA/RHA replacement, and corrosion activity as measured with potentiostat equipment improved by an average of 34% . These results indicate a clear performance improvement of the modified concrete that is proportional to the percent replacement of cement.
Show less - Date Issued
- 2010
- PURL
- http://purl.flvc.org/FAU/2138109
- Subject Headings
- Fracture mechanics, Concrete, Additives, Testing, Fly ash, Testing, Concrete, Cracking, Prevention, Industrial minerals, Testing
- Format
- Document (PDF)
- Title
- Experimental evaluation of the durability of fly ash-based geopolymer concrete in the marine environment.
- Creator
- Edouard, Jean-Baptiste., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
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The construction industry is increasingly turning to the use of environmentally friendly materials in order to meet the sustainable aspect required by modern infrastructures. Consequently, for the last two decades, the expansion of this concept, and the increasing global warming have raised concerns on the extensive use of Portland cement due to the high amount of carbon dioxide gas associated with its production. The development of geopolymer concretes offers promising signs for a change in...
Show moreThe construction industry is increasingly turning to the use of environmentally friendly materials in order to meet the sustainable aspect required by modern infrastructures. Consequently, for the last two decades, the expansion of this concept, and the increasing global warming have raised concerns on the extensive use of Portland cement due to the high amount of carbon dioxide gas associated with its production. The development of geopolymer concretes offers promising signs for a change in the way of producing concrete. However, to seriously consider geopolymer binders as an alternative to ordinary Portland cement, the durability of this new material should be evaluated in any comparative analysis. The main purpose of this study was to evaluate the durability characteristics of low calcium fly ash-based geopolymer concretes subjected to the marine environment, compared to ordinary Portland cement concrete with similar exposure. To achieve this goal, 8 molar geopolymer, 14 molar geopolymer and ordinary Portland cement concrete mixes were prepared and tested for exposure in seawater. Compressive strengths in the range of 2900 to 8700 psi (20-60 MPa) were obtained. The corrosion resistance performance of steel-reinforced concrete beams, made of these mixes, was also studied, using an accelerated electrochemical method, with submergence in salt water. The test results indicated that the geopolymer concrete showed excellent resistance to chloride attack, with longer time to corrosion cracking, compared to ordinary Portland cement concrete.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3170960
- Subject Headings
- Reinforced concrete, Corrosion, Testing, Reinforced concrete construction, Concrete, Mixing, Quality control, Environmental chemistry, Industrial applications, Polymer composites
- Format
- Document (PDF)
- Title
- Centrally prestressed fiber reinforced concrete columns.
- Creator
- Grijalba, Daniel A., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
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With the need to improve corrosion resistance in columns and piles, the innovative idea of Centrally Prestressed Fiber Reinforced Concrete (CPFRC) columns is a promising solution. The first step is to compare if the compressive strength of any mix is affected by the size, geometry, or even the inclusion of polyolefin fibers in a specimen. The results showed that the cylinder size of 4 in. x 8 in., which is the most common size used by the testing labs, has the highest compressive strength....
Show moreWith the need to improve corrosion resistance in columns and piles, the innovative idea of Centrally Prestressed Fiber Reinforced Concrete (CPFRC) columns is a promising solution. The first step is to compare if the compressive strength of any mix is affected by the size, geometry, or even the inclusion of polyolefin fibers in a specimen. The results showed that the cylinder size of 4 in. x 8 in., which is the most common size used by the testing labs, has the highest compressive strength. There was no sign on compressive strength improvement with the use of polyolefin fibers, except for reduction in cracking size and concrete spalling. The second step compared the ultimate strength, ductility characteristics and failure mode of CPFRC columns to conventional columns. CPFRC showed adequate axial and flexural resistance, in addition to ductile behavior similar to regular reinforced concrete columns.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3332253
- Subject Headings
- Prestressed concrete construction, Strength of materials, Composite reinforced concrete, Concrete, Chemical resistance
- Format
- Document (PDF)
- Title
- Durability prediction of recycled aggregate concrete under accelerated aging and environmental exposure.
- Creator
- Gonzalez, Lillian, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
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This study is to compare the performance of recycled aggregate concrete and the impact of up to 50% cement replacement with fly ash on durability. Water content, sieve analysis, standard and modified compaction tests were performed to assess the physical properties of the recycled aggregate concrete. Accelerated aging tests were performed to predict the long term durability of the recycled aggregate concrete. Following Arrhenius modeling and TTS and SIM accelerated aging protocols, a time...
Show moreThis study is to compare the performance of recycled aggregate concrete and the impact of up to 50% cement replacement with fly ash on durability. Water content, sieve analysis, standard and modified compaction tests were performed to assess the physical properties of the recycled aggregate concrete. Accelerated aging tests were performed to predict the long term durability of the recycled aggregate concrete. Following Arrhenius modeling and TTS and SIM accelerated aging protocols, a time versus stiffness master curve was created. This allowed the prediction of equivalent age using experimental data and theoretical analysis. To account for environmental exposure, the specimens underwent 24 and 48 hours of wet-dry cycling and subjected. Overall there was an increase in stiffness and strength from the specimens containing fly ash. All tests performed predicted equivalent age beyond the testing period of 144 hrs. and up to 7 years. Specimens containing fly maintained a constant and higher density to environmental exposure.
Show less - Date Issued
- 2010
- PURL
- http://purl.flvc.org/FAU/3353087
- Subject Headings
- Concrete, Mechanical properties, Testing, Concrete, Environmental aspects, Sustainable construction, High strength concrete, Testing, Cement composites, Testing
- Format
- Document (PDF)
- Title
- Strength and Modulus of Recycled Aggregate Concrete Subjected to Wetting and Drying Cycles.
- Creator
- Alawadi, Farah, Sobhan, Khaled, Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
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The reuse of crushed aggregates for producing structural concrete is a major concern especially when it comes to its strength and durability. This study evaluated recycled aggregate concrete (RAC) for its strength and durability under simulated environmental degradation in the form of wetting-drying (W-D) cycles. The study consisted of two phases, each involving the determination of the compressive strength and modulus of elasticity using the conventional method and also a nondestructive...
Show moreThe reuse of crushed aggregates for producing structural concrete is a major concern especially when it comes to its strength and durability. This study evaluated recycled aggregate concrete (RAC) for its strength and durability under simulated environmental degradation in the form of wetting-drying (W-D) cycles. The study consisted of two phases, each involving the determination of the compressive strength and modulus of elasticity using the conventional method and also a nondestructive ultrasonic pulse velocity method (Pundit Lab). Phase 1 involved 7-day curing followed by 30 W-D cycles, while Phase 2 included 28-day cured samples subjected to 15 W-D cycles. It was found that RAC specimens subjected to W-D cycles had minimal degradation in strength, making the use of RAC in construction very promising. Results from Pundit Lab compared reasonably well with conventional test results, showing promise as a nondestructive tool for the evaluation of RAC properties.
Show less - Date Issued
- 2018
- PURL
- http://purl.flvc.org/fau/fd/FA00013162
- Subject Headings
- Concrete, Durability of concrete, Strength of materials, Recycled aggregate concrete
- Format
- Document (PDF)
- Title
- Nanotechology in concrete: review and statistical analysis.
- Creator
- Glenn, Jonathan., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
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This thesis investigates the use of nanotechnology in an extensive literature search in the field of cement and concrete. A summary is presented. The research was divided into two categories: (1) nanoparticles and (2) nanofibers and nanotubes. The successes and challenges of each category is documented in this thesis. The data from the literature search is taken and analyzed using statistical prediction by the use of the Monte Carlo and Bayesian methods. It shows how statistical prediction...
Show moreThis thesis investigates the use of nanotechnology in an extensive literature search in the field of cement and concrete. A summary is presented. The research was divided into two categories: (1) nanoparticles and (2) nanofibers and nanotubes. The successes and challenges of each category is documented in this thesis. The data from the literature search is taken and analyzed using statistical prediction by the use of the Monte Carlo and Bayesian methods. It shows how statistical prediction can be used to analyze patterns and trends and also discover optimal additive dosages for concrete mixes.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fcla/dt/3360786
- Subject Headings
- Nanostructured materials, Nanofibers, Cement, Additives, Concrete, Additives
- Format
- Document (PDF)
- Title
- Adhesive Joint Analyses Using Ansys CZM Modeling of a Prefabricated Hybrid Concrete-GFRP-CFRP Unit.
- Creator
- Kabaluk, Maksim, Arockiasamy, Madasamy, Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
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The present study reviews applications of FRP materials joined by structural adhesives in civil engineering. FE analysis with mix-mode cohesive zone material model (CZM) was used to analyze stresses induced in two structural adhesives joining dissimilar materials (concrete GFRP-CFRP) of the hybrid-composite unit. The predicted failure loads, displacements and deformation by the 3-D non-linear FE analysis in the present study are in good agreement with the experimental results of the hybrid...
Show moreThe present study reviews applications of FRP materials joined by structural adhesives in civil engineering. FE analysis with mix-mode cohesive zone material model (CZM) was used to analyze stresses induced in two structural adhesives joining dissimilar materials (concrete GFRP-CFRP) of the hybrid-composite unit. The predicted failure loads, displacements and deformation by the 3-D non-linear FE analysis in the present study are in good agreement with the experimental results of the hybrid-composite unit reported by Deskovic et al. (1995). The contact analysis revealed a complex 3-D state of stress in the bondlines of both structural adhesives. It is concluded that higher joint strength is expected when a ductile adhesive is used.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013222
- Subject Headings
- Adhesive joints, Fiber reinforced polymers, Composites, Concrete
- Format
- Document (PDF)