The Experts below are selected from a list of 123 Experts worldwide ranked by ideXlab platform
Roy Scandrol - One of the best experts on this subject based on the ideXlab platform.
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Commercial Demonstration of the Manufactured Aggregate Processing Technology Utilizing Spray Dryer Ash
2005Co-Authors: Roy ScandrolAbstract:This quarterly report covers the period from January 1, 2005 through March 31, 2005. It covers: technical development, permitting status, engineering status, construction status, operations summary and marketing support activities for this period. Plant startup is still continuing. Testing of admixtures to enhance extrusion and SDA wetting is continuing. Efforts are underway to improve plant availability
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Commercial Demonstration of the Manufactured Aggregate Processing Technology Utilizing Spray Dryer Ash
2005Co-Authors: Roy ScandrolAbstract:This quarterly report covers the period from October 1st, 2004 through December 31st, 2004. It covers: technical development, permitting status, engineering status, construction status, operations summary and marketing support activities for this period. Plant startup is still continuing. Testing of admixtures to enhance extrusion and SDA wetting is continuing. Green extrudates and embedding material were loaded into the curing vessel on October 14th. The whole plant was integrated on December 16th. Efforts are underway to improve plant availability
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Commercial Demonstration of the Manufactured Aggregate Processing Technology Utilizing Spray Dryer Ash
2004Co-Authors: Roy ScandrolAbstract:This quarterly report covers the period from July 1st, 2004 through September 30th, 2004. It covers: technical development, permitting status, engineering status, construction status, operations summary and marketing support activities for this period. Plant startup, including equipment and system debugging, is underway. Minor adjustments to the SDA feed system, pug mill, and extruder were completed. Testing of admixtures to prevent the wetted SDA from sticking is continuing. The power plant is implementing a lime optimization program to reduce the calcium hydroxide values in the ash
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COMMERCIAL DEMONSTRATION OF THE Manufactured Aggregate PROCESSING TECHNOLOGY UTILIZING SPRAY DRYER ASH
2003Co-Authors: Roy ScandrolAbstract:This quarterly report covers the period from July 1st, 2003 through September 30th, 2003. It covers; technical development, permitting status, engineering status, construction status, operations summary and marketing support activities for this period
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COMMERCIAL DEMONSTRATION OF THE Manufactured Aggregate PROCESSING TECHNOLOGY UTILIZING SPRAY DRYER ASH
2003Co-Authors: Roy ScandrolAbstract:Universal Aggregates, LLC proposes to design, construct and operate a lightweight Aggregate manufacturing plant at the Birchwood Power Facility in King George, Virginia. The installation and start-up expenses for the Birchwood Aggregate Facility are $19.5 million. The DOE share is $7.2 million (37%) and the Universal Aggregates share is $12.3 (63%). The project team consists of CONSOL Energy Inc., P.J. Dick, Inc., SynAggs, LLC, and Universal Aggregates, LLC. The Birchwood Facility will transform 115,000 tons per year of spray dryer by-products that are currently being disposed of in an offsite landfill into 167,000 tons of a useful product, lightweight Aggregates that can be used to manufacture lightweight Aggregates that can be used to manufacture lightweight and medium weight masonry blocks. In addition to the environmental benefits, the Birchwood Facility will create nine (9) manufacturing jobs plus additional employment in the local trucking industry to deliver the Aggregate to customers or reagents to the facility. A successful demonstration would lead to additional lightweight Aggregate manufacturing facilities in the United States. There are currently twenty-one (21) spray dryer facilities operating in the United States that produce an adequate amount of spray dryer by-product to economically justify the installation of a lightweight Aggregate manufacturing facility. Industry sources believe that as additional scrubbing is required, dry FGD technologies will be the technology of choice. Letters from potential lightweight Aggregate customers indicate that there is a market for the product once the commercialization barriers are eliminated by this demonstration project
E.r. Cunha - One of the best experts on this subject based on the ideXlab platform.
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Comparison of natural and Manufactured fine Aggregates in cement mortars
Cement and Concrete Research, 2007Co-Authors: Jardel Pereira Gonçalves, Luís Marcelo Tavares, R. D. Toledo Filho, Eduardo De Moraes Rego Fairbairn, E.r. CunhaAbstract:Abstract The performance of cement mortars using Manufactured fine Aggregates produced by cone crushing or impact crushing has been compared to that of mortars prepared from a natural sand control-sample. Samples from both crusher products have been additionally subjected to classification for partial removal of fines, being also used in preparing mortars. Particle shape analyses indicated that material produced by impact crushing presented intermediate sphericity and aspect ratio, between those found in natural fine Aggregate and cone-crushed material, and that the aspect ratio of the cone-crushed material increased for finer particle sizes. The unclassified impact crusher product presented the highest packing density, and mortars produced from it had comparatively low porosity and low absorptivity and the highest unconfined compressive strength. The classified product from cone crushing presented low packing density and mortars were characterized by the highest porosities, absorptivities and lowest unconfined compressive strength, probably mostly due to its poor particle shapes. Modeling of the stress–strain response with scalar damage mechanics showed that Manufactured Aggregate produced from classification of the cone crusher yielded a mortar with highly inelastic deformation response, whereas mortars produced from unclassified product of impact crushing showed more elastic deformation response. Results were also analyzed in light of de Larrard's Compressible Packing Model.
Idrees Zafar - One of the best experts on this subject based on the ideXlab platform.
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Characterization of processed lightweight Aggregate and its effect on physical properties of concrete
Construction and Building Materials, 2020Co-Authors: Fahad K. Alqahtani, Idrees ZafarAbstract:Abstract The plastic because of its lightweight and flexibility to adopt the required shapes has led in an enormous increase in production of plastic products during recent years. To minimize the negative environmental impacts of plastic waste, many industrial sectors have tried to recycle and utilize the plastic waste. Among the other sectors, concrete industry can be considered as one of the alternatives such as to use the recycled plastic as Aggregate replacement in concrete. A processed lightweight Aggregates (PLA) has been Manufactured using the plastic waste and other local materials using a compression moulding press technique. The detailed characterization of the PLA was also conducted. In addition, the effect of PLA incorporation on the physical properties of concrete along with effect of curing temperature on the compressive strength was also tested. The addition of Manufactured Aggregate in concrete has increased the Poisson’s ratio, thermal conductivity values while the density, and compressive strength were found to be reduced as compared to control mix. It was also noticed that PLA concrete can be cured at temperatures up to 30 °C, without significantly affecting compressive strength. The PLA has shown the prospective to be used in lightweight concrete applications.
R.m. Statnick - One of the best experts on this subject based on the ideXlab platform.
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CHARACTERIZATION OF COAL COMBUSTION BY-PRODUCTS FOR THE RE-EVOLUTION OF MERCURY INTO ECOSYSTEMS
2001Co-Authors: J.a. Withum, R.m. StatnickAbstract:EPA and state environmental agencies are suggesting that mercury (Hg) in coal combustion by-products is re-emitted into local ecosystems by additional processing to final products (i.e., wallboard, etc.), by dissolution into groundwater, or by reactions with anaerobic bacteria. This perception may limit the opportunities to use coal combustion by-products in recycle/reuse applications. In this program, CONSOL Energy is conducting a comprehensive sampling and analytical program to address this concern. If the results of this work demonstrate that re-emissions of Hg from waste disposal and by-product utilization are over-stated, additional regulations regarding coal combustion, waste disposal, and waste material utilization will not be required. This will result in continued low energy cost that is beneficial to the national economy and stability of local economies that are dependent on coal. In this quarter, laboratory equipment was assembled and blank test runs were made, Manufactured Aggregate and spray dryer ash samples were collected and leached, and fly ash and FGD slurry samples from an Ohio bituminous coal-fired utility were collected for leaching.
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Production of Manufactured Aggregates from flue gas desulfurization by-products
1999Co-Authors: D.c. Mccoy, J.a. Withum, M.l. Fenger, R.o. Scandrol, R.a. Winschel, R.m. StatnickAbstract:CONSOL R and D has developed a disk pelletization process to produce Manufactured Aggregates from the by-products of various technologies designed to reduce sulfur emissions produced from coal utilization. Aggregates have been produced from the by-products of the Coolside and LIMB sorbent injection, the fluidized-bed combustion (FBC), spray dryer absorption (SDA), and lime and limestone wet flue gas desulfurization (FGD) processes. The Aggregates produced meet the general specifications for use as road Aggregate in road construction and for use as lightweight Aggregate in concrete masonry units. Small field demonstrations with 1200 lb to 5000 lb of Manufactured Aggregates were conducted using Aggregates produced from FBC ash and lime wet FGD sludge in road construction and using Aggregates made from SDA ash and lime wet FGD sludge to manufacture concrete blocks. The Aggregates for this work were produced with a bench-scale (200--400 lb batch) unit. In 1999, CONSOL R and D constructed and operated a 500 lb/hr integrated, continuous pilot plant. A variety of Aggregate products were produced from lime wet FGD sludge. The pilot plant test successfully demonstrated the continuous, integrated operation of the process. The pilot plant demonstration was a major step toward commercialization of Manufactured Aggregate production frommore » FGD by-products. In this paper, progress made in the production of Aggregates from dry FGD (Coolside, LIMB, SDA) and FBC by-products, and lime wet FGD sludge is discussed. The discussion covers bench-scale and pilot plant Aggregate production and Aggregate field demonstrations.« less
Gabriel J. Assaf - One of the best experts on this subject based on the ideXlab platform.
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Finding an Optimal Bitumen and Natural Sand Balance for Hot Mix Asphalt Concrete in Hot and Arid Regions
Solving Pavement and Construction Materials Problems with Innovative and Cutting-edge Technologies, 2018Co-Authors: Fathi S. Almadwi, Gabriel J. AssafAbstract:Designing a Hot Mix Asphalt Concrete (HMAC) for Libya’s southern desert regions has two serious challenges. Due to the extremely hot and arid conditions, where road surfaces can be reaching 70 °C, and with air humidity well below 50%, a HMAC in the southern desert often suffers great deformations in the form of rutting. This is particularly a problem in lower-volume roads because the remoteness and the low traffic of these roads makes an investment in their construction and repair not cost effective to use higher-grade materials. This paper shows comparative data for paving mix performance of two bitumen grades available in Libya, both under simulated climatic conditions. These are used to select the best mix of sand and bitumen. The research first determines the best mix of natural desert sand with Manufactured Aggregate. Then it uses this sand mix as a control to evaluate two kinds of bitumen, Bitumen 60/70 (B60/70) and PG70-10. With a fine Aggregate mix of 33% natural desert sand (from the region) and 63% Manufactured crush fine Aggregate, the performance of PG70-10 was found to be superior compared with B60/70. These are assessed with the Marshall test, the Super Gyratory Compactor test, and the wheel track test in the ETS Laboratories (Ecole de technologie superieure) Faculty of Engineering of the University of Quebec, Canada. This finding is important for designers working in arid conditions as a way of sizable cost savings by substituting available materials, i.e. the rounded sands of desert regions for more expensive sands imported from other regions.
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The Effect of Using Desert Sands and Cement to Stabilize the Base Course Layer of Roads in Libya
Sustainable Civil Infrastructures, 2018Co-Authors: Talal Amhadi, Gabriel J. AssafAbstract:This paper investigates using a mixture of natural sand, Portland cement, and Manufactured Aggregates to stabilize the base course layer for low-volume roads. Compaction and resistance to deformation California Bearing Ratio (CBR) results are measured and guidelines provided with consideration for hot desert areas like Libya. These tests have been conducted to provide relevant statistical conclusions and recommendations as to how much round-shaped sand may be used versus Manufactured crushed sand for various traffic loads. In the last 15–20 years, Libya, along with many other developing countries in the area, has undergone a sizeable move towards modernization, including upgrading the road infrastructure that services the growing population. Such a project runs into challenges in areas with lower population density, that require that roadwork projects be kept under sharp cost constraints. Using a mixture of sand cement to stabilize the base course has been common for decades because the properties of cement improve the characteristics of natural sand; furthermore, when the road is built in a sandy desert, the use of desert sand is an obvious solution to containing costs. Nonetheless, natural sands have been rounded by years of mechanical action by environmental forces, and are therefore rounder and more prone to shifting than angular Manufactured sand. Manufactured Aggregates need to be imported from elsewhere in the country and so have higher costs and environmental considerations, both of which give these projects incentives to use the local desert sand. This paper only considers the use of Manufactured Aggregate of 0–5 mm in the base course and examines how using local desert sand in the Aggregate mix can reduce costs. This solution brings with it many problems because, due to natural sand’s lower inherent stability with regards to Manufactured sand, the road surface will degrade faster. The solution to this problem, presented here, is to relocate some of the strength of the road from the surface layer to the base course layer. This is done by reducing the thickness of the asphalt course to a minimum, and introducing more structural strength in the base course layer by means of a cement-stabilized base layer.
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Performance Testing of Paving Mixes for Libya’s Hot and Arid Conditions, Using Marshall Stability and SUPERPAVE Gyratory Compactor Methods
Advancement in the Design and Performance of Sustainable Asphalt Pavements, 2017Co-Authors: Fathi S. Almadwi, Gabriel J. AssafAbstract:Asphalt Concrete Pavements (ACP) in Libya’s southern desert regions suffer two major challenges: the hot and arid climate, with road surface temperatures reaching 65–70 °C, and air humidity below 50%. As such, ACP in Libya develops excessive deformation. The lack of modern testing methods and in-situ monitoring during the use-phase make predicting the performance of new mix designs difficult. This paper aims to provide comparative performance data on paving mixes of different Libya-sourced bitumen grades under simulated climate conditions, and to compare the usefulness of empirical testing methods (Marshall) to Performance Graded methods. Two mixes, one using Bitumen 60/70 (B 60/70) and the other using PG70-10, are assessed with Marshall Stability and Super Gyratory Compactor tests, using modern equipment at the laboratory of the ETS (Ecole de technologie superieure) faculty of engineering of the University of Quebec, Canada. The performance of PG70-10 mixes is found to be superior to that of the performance of the mixes using B 60/70. The PG70-10 mix performed within the requirements of lower-volume roads (≤300 vehicles per day). Also, the results of the Super Gyratory Compactor tests are found to be a better indicator of in-service performance than those given by Marshall Stability tests. These results provide a foundation for performance-testing of different paving mixes that varied in sand and filler content; these are available for applications in similar arid climates, and may provide significant savings by allowing engineers to substitute local materials, such as the abundant rounded sand in southern Libya, for more scarce and costly materials, such as Manufactured Aggregate.