The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Yan Zeyu - One of the best experts on this subject based on the ideXlab platform.
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Mechanical properties of discrete BFRP needles reinforced seawater sea-sand Concrete-filled GFRP tubular stub columns
Construction and Building Materials, 2020Co-Authors: Zhiqiang Dong, Xiao Ling Zhao, Hong Zhu, Yang Wei, Yan ZeyuAbstract:Abstract This paper proposes a new type of tubular column, which is composed of glass fiber-reinforced polymer (GFRP) tube and discrete basalt fiber-reinforced polymer (BFRP) needles reinforced seawater sea-sand Concrete (SWSSC). The discrete BFRP needles, with an aspect ratio of 10.0, were cut from BFRP bar production scrap and mixed into fresh Concrete to replace 20% of the coarse aggregates by volume. The axial compression properties and lateral bending properties of the tubular columns were tested. The test variables included the wall thickness of the GFRP tubes (i.e., 3 mm and 4 mm), the type of coarse aggregates (i.e., Gravel or coral), and the incorporation of BFRP needles or not. Additionally, unconfined bare columns were tested for comparison. The test results showed that the inclusion of BFRP needles had moderate adverse effects on the peak compressive strength of bare columns: the peak axial stress reduced slightly by 2.5% for Gravel Concrete and 7.2% for coral Concrete, respectively. Besides, for the four types of Concrete in this paper, the 3- and 4-mm GFRP tube-confinement increased the peak axial compressive strengths by 23 ~ 52% and 65 ~ 83%, respectively. In addition, the adoption of GFRP tubes was able to improve the bending performance of columns significantly, especially for energy consumption.
Zhiqiang Dong - One of the best experts on this subject based on the ideXlab platform.
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Mechanical properties of discrete BFRP needles reinforced seawater sea-sand Concrete-filled GFRP tubular stub columns
Construction and Building Materials, 2020Co-Authors: Zhiqiang Dong, Xiao Ling Zhao, Hong Zhu, Yang Wei, Yan ZeyuAbstract:Abstract This paper proposes a new type of tubular column, which is composed of glass fiber-reinforced polymer (GFRP) tube and discrete basalt fiber-reinforced polymer (BFRP) needles reinforced seawater sea-sand Concrete (SWSSC). The discrete BFRP needles, with an aspect ratio of 10.0, were cut from BFRP bar production scrap and mixed into fresh Concrete to replace 20% of the coarse aggregates by volume. The axial compression properties and lateral bending properties of the tubular columns were tested. The test variables included the wall thickness of the GFRP tubes (i.e., 3 mm and 4 mm), the type of coarse aggregates (i.e., Gravel or coral), and the incorporation of BFRP needles or not. Additionally, unconfined bare columns were tested for comparison. The test results showed that the inclusion of BFRP needles had moderate adverse effects on the peak compressive strength of bare columns: the peak axial stress reduced slightly by 2.5% for Gravel Concrete and 7.2% for coral Concrete, respectively. Besides, for the four types of Concrete in this paper, the 3- and 4-mm GFRP tube-confinement increased the peak axial compressive strengths by 23 ~ 52% and 65 ~ 83%, respectively. In addition, the adoption of GFRP tubes was able to improve the bending performance of columns significantly, especially for energy consumption.
Stephen A Cross - One of the best experts on this subject based on the ideXlab platform.
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High Dosage Type-C Fly Ash and Limestone in Sand-Gravel Concrete
Transportation Research Record, 1996Co-Authors: Mohamed Nagib Abou-zeid, John Wojakowski, Stephen A CrossAbstract:Alkali-silica reactions are a major cause of Concrete deterioration. The reactions can lead to severe damage that may ultimately endanger the performance and safety of Concrete structures. The use of fly ash as partial replacement of Portland cement and the use of some limestone in Concrete mixtures were considered as two potential approaches to minimize the severity of the problem. Sand-Gravel Concrete mixtures were prepared by replacing 15, 25, and 35 percent, by weight of Portland cement, with an equal weight of ASTM Type C fly ash. In those mixtures, either 30 percent or 50 percent of the total aggregate was limestone. Concrete beams were prepared and the wetting-and-drying test was performed in accordance with Kansas Department of Transportation (KDOT) specifications. Also, freeze-and-thaw testing of Concrete beams were performed on some selected mixtures. Results indicate that most of the fly ash Concrete mixtures with 30 percent limestone do not fulfill the requirements of the KDOT specifications. ...
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High Dosage Type-C Fly Ash and Limestone in Sand-Gravel Concrete
Transportation Research Record: Journal of the Transportation Research Board, 1996Co-Authors: Mohamed Nagib Abou-zeid, John Wojakowski, Stephen A CrossAbstract:Alkali-silica reactions are a major cause of Concrete deterioration. The reactions can lead to severe damage that may ultimately endanger the performance and safety of Concrete structures. The use of fly ash as partial replacement of Portland cement and the use of some limestone in Concrete mixtures were considered as two potential approaches to minimize the severity of the problem. Sand-Gravel Concrete mixtures were prepared by replacing 15, 25, and 35 percent, by weight of Portland cement, with an equal weight of ASTM Type C fly ash. In those mixtures, either 30 percent or 50 percent of the total aggregate was limestone. Concrete beams were prepared and the wetting-and-drying test was performed in accordance with Kansas Department of Transportation (KDOT) specifications. Also, freeze-and-thaw testing of Concrete beams were performed on some selected mixtures. Results indicate that most of the fly ash Concrete mixtures with 30 percent limestone do not fulfill the requirements of the KDOT specifications. The fly ash mixtures with 50 percent limestone yield better results; most of them meet the specifications. Results also show that increasing the fly ash dosage does not seem as effective as introducing limestone for alleviating alkali-silica reaction problems.
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USE OF ASTM TYPE-C FLY ASH AND LIMESTONE IN SAND-Gravel Concrete
Transportation Research Record, 1995Co-Authors: Mohamed Nagib Abou-zeid, John Wojakowski, Stephen A CrossAbstract:Serious damage in Concrete structures worldwide has been attributed to alkali-aggregate reactions. Field and laboratory work has demonstrated that silicious aggregates in wide regions in the midwestern United States can yield Concrete with durability problems. This is the case for some sand-Gravel aggregates in Kansas. To minimize durability problems, pozzolans, such as fly ash and limestone, have been suggested for use in Concrete mixtures involving such aggregates. The use of two ASTM type-C fly ashes at 15% replacement of portland cement is evaluated. Also, the use of limestone (sweetener) from two sources as a 30% weight replacement of the sand-Gravel is investigated. Thirty Concrete mixtures were prepared with a water-to-cementitious materials ratio of 0.51. Eight approved and unapproved types of sand-Gravel aggregates from different areas in Kansas were used. Concrete beams were cast and tested to determine the change in lengths and the modulus of rupture. Test results indicate that mixtures made with the two fly ashes have higher expansion and lower modulus of rupture when compared with mixtures containing no fly ash. Of the 16 Concrete mixtures made with fly ash 15 failed to meet Kansas Department of Transportation specifications. The mixtures made with unapproved sand Gravel and limestone had lower expansion and higher modulus of rupture when compared with Concrete made with approved aggregates with no fly ash.
Mark B Snyder - One of the best experts on this subject based on the ideXlab platform.
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FACTORS AFFECTING DETERIORATION OF TRANSVERSE CRACKS IN JOINTED REINFORCED Concrete PAVEMENTS
Transportation Research Record, 1991Co-Authors: Zafar I Raja, Mark B SnyderAbstract:Jointed reinforced Concrete pavements (JRCP) develop transverse cracks as the drying and thermal shrinkage of the Concrete is resisted by friction with the supporting layers. These cracks deteriorate with time and traffic due to loss of aggregate-interlock load transfer capacity. This report describes the first year of a laboratory investigation to determine the relative effects of a few selected factors (coarse aggregate type, gradation, and treatment) on transverse crack deterioration in JRCP. The work described herein focused on the development, execution, collection and analysis of load transfer data from the testing of a series of large-scale pavement test specimens that were subjected to repeated applications of loads simulating the passage of heavy truck traffic. Test results indicate that slabs cast using crushed limestone and natural Gravel graded to meet Michigan Department of Transportation specification 6A (1.5 inch top size, coarser gradation) perform comparably while specimens cast using similarly graded slag deteriorate much more rapidly. The use of more finely graded Gravels meeting MDOT specification 17A (1.0 inch top size, finer gradation) resulted in performance only slightly worse than that of the larger Gravel. Finally, specimens using 100% recycled Gravel Concrete (6A gradation) or a blend of recycled Gravel Concrete and large crushed limestone (MDOT gradation 4A, 2.5 inch top size) performed only slightly better than the slag specimen. Test results also suggest that the amount of temperature steel currently used in Michigan JRCP (0.17% by area of Concrete) may be insufficient to endure the combined effects of repeated truck traffic and environmental loads.
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FACTORS AFFECTING DETERIORATION OF TRANSVERSE CRACKS IN JOINTED REINFORCED Concrete PAVEMENTS. FINAL REPORT
1991Co-Authors: Mark B Snyder, Zafar I RajaAbstract:Jointed reinforced Concrete pavements (JRCP) develop transverse cracks as the drying and thermal shrinkage of the Concrete is resisted by friction with the supporting layers. These cracks deteriorate with time and traffic due to loss of aggregate-interlock load transfer capacity. This report describes the first year of a laboratory investigation to determine the relative effects of a few selected factors (coarse aggregate type, gradation, and treatment) on transverse crack deterioration in JRCP. The work described herein focused on the development, execution, collection and analysis of load transfer data from the testing of a series of large-scale pavement test specimens that were subjected to repeated applications of loads simulating the passage of heavy truck traffic. Test results indicate that slabs cast using crushed limestone and natural Gravel graded to meet Michigan Department of Transportation specification 6A (1.5 in. top size, coarser gradation) perform comparably while specimens cast using similarly graded slag deteriorate much more rapidly. The use of more finely graded Gravels meeting MDOT specification 17A (1.0 in. top size, finer gradation) resulted in performance only slightly worse than that of the larger Gravel. Finally, specimens using 100% recycled Gravel Concrete (6A gradation) or a blend of recycled Gravel Concrete and large crushed limestone (MDOT gradation 4A, 2.5 in. top size) performed only slightly better than the slag specimen. Test results also suggest that the amount of steel currently used in Michigan JRCP (0.17% by area of Concrete) may be insufficient to endure the combined effects of repeated truck traffic and environmental loads.
Y. G. Balami - One of the best experts on this subject based on the ideXlab platform.
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Assessment of the Properties of Rubberized Bama Gravel Concrete using Destructive Method
International journal of sciences, 2018Co-Authors: A. T. Gubio, L. O. Onundi, Y. G. BalamiAbstract:From the twentieth first century to date, the world has seen a rapid production of non-biodegradable materials like rubber with some having less than a decade expiry date such as vehicle tyres. This has generated enormous amount of solid waste which can be best managed by recycling methods; recycling in Concrete is one possible means of achieving this goal since it’s the single most widely used material in the world. Although Concrete compressive strength is reduced by addition of rubber depending on the percentage of rubber added and the average size of rubber used as aggregate. This study investigates Rubberized Bama Gravel Concrete (RBGC) when three varied contents of rubber (10%, 20% and 30% by mass) were used to replace the mineral aggregate for both fine and coarse rubber aggregates respectively as compared to the controlled mix. A mix ratio of 1:1½:3 and 1:2:4, and water cement ratio of 0.5 and 0.6 were respectively used during the investigation. Tests carried out on Bama aggregate were specific gravity, aggregate impact and aggregate crushing; and on Concrete are workability, density and destructive compressive strength. The study has shown that rubberized Concrete is weak in compressive strength. But they have good water resistance with low absorption, low shrinkage and high impact resistance.The reduction in compressive strength of 10% fine rubber aggregate is about 10% which could be used as a structural member, while others (20%, 30% fine rubber aggregate and 10%, 20%, 30% chipped rubber aggregate) cannot be used as structural members as there is a significant decrease in compressive strength of Concrete but rather as floors, kerbs, blocks and other non-structural.
