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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

Liquid Coatings for Reducing Corrosion of Steel in Concrete

Inorganic coating materials are being developed to slow or stop corrosion of reinforcing steel members inside concrete structures. It is much simpler and easier to use these coating materials than it is to use conventional corrosion-inhibiting systems based on impressed electric currents. Unlike impressed electrical corrosion-inhibiting systems, these coatings do not require continuous consumption of electrical power and maintenance of power-supply equipment. Whereas some conventional systems involve the use of expensive arc-spray equipment to apply the metallic zinc used as the sacrificial anode material, the developmental coatings can be applied by use of ordinary paint sprayers. A coating material of the type under development is formulated as a liquid containing blended metallic particles and/or moisture-attracting compounds. The liquid mixture is sprayed onto a concrete structure. Experiments have shown that even though such a coat resides on the exterior surface, it generates a protective galvanic current that flows to the interior reinforcing steel members. By effectively transferring the corrosion process from the steel reinforcement to the exterior coating, the protective current slows or stops corrosion of the embedded steel. Specific formulations have been found to meet depolarization criteria of the National Association of Corrosion Engineers (NACE) for complete protection of steel reinforcing bars ("rebar") embedded in concrete.

MacDowell, Louis G.↗
NASA NTRS1973

Losses due to weather phenomena in the bituminous concrete construction industry in Wisconsin

The losses (costs) due to weather phenomena as they affect the bituminous concrete industry in Wisconsin were studied. The bituminous concrete industry's response to precipitation, in the form of rain, is identified through the use of a model, albeit crude, which identifies a typical industry decision-response mechanism. Using this mechanism, historical weather data and 1969 construction activity, dollar losses resulting from rain occurrences were developed.

Kuhn, H. A. J.↗
NASA NTRS1974

Portable apparatus with CRT display for nondestructive testing of concrete by the ultrasonic pulse method

The development of methods for the nondestructive study of concrete structures is discussed. The nondestructive test procedure is based on the method of ultrasonic pulse transmission through the material. The measurements indicate that the elastic properties of concrete or other heterogeneous materials are a function of the rate of ultrasonic propagation. Diagrams of the test equipment are provided. Mathematical models are included to support the theoretical aspects.

Manta, G.↗
NASA NTRS1974

Concerning the sound insulation of building elements made up of light concretes

The sound insulating capacity of building elements made up of light concretes is considered. Analyzing differentially the behavior of light concrete building elements under the influence of incident acoustic energy and on the basis of experimental measurements, coefficients of correction are introduced into the basic formulas for calculating the sound insulating capacity for the 100-3,2000 Hz frequency band.

Giurgiu, I. I.↗
NASA NTRS1977

Plastic (wire-combed) grooving of a slip-formed concrete runway overlay at Patrick Henry Airport: An initial evaluation

A wire-comb technique is described for transversely grooving the surface of a freshly laid (plastic state) slip-formed concrete overlay installed at Patrick Henry Airport. This method of surface texturing yields better water drainage and pavement skid resistance than that obtained with an older conventional burlap drag concrete surface treatment installed on an adjacent portion of the runway.

Marlin, E. C.↗
NASA NTRS1977

Application of the endochronic theory of viscoplasticity to solid propellants and sandasphalt concrete

Solid propellants, sand-asphalt concrete and hard plastics showed rate sensitive mechanical behavior which, in addition, indicated that these materials have a permanent memory of the strain (or loading) path by which their present state was attained. A constitutive equation was formulated in general three dimensional tensorial form by means of irreversible thermodynamics. By using a very simple analytical form, it was shown that the mechanical behavior of solid propellants and sand-asphalt concrete can be readily described.

Peng, S. T. J.↗
NASA NTRS1978

Heat and moisture flow in concrete as a function of temperature

Due to temperature, reactors in operation cause heat and moisture flows in the thick walled prestressed pressure vessels. These flows were studied in three beams of concrete made with crushed limestone aggregate, and in three beams made of crushed gravel/sand aggregate. The flow phenomena were related to the structural development of the concrete by determining the amount of non-evaporatable water, the total porosity, and the pore size distribution. Local temperature and moisture conditions also influenced the technical properties. Compressive strength, changes in length due to shrinkage and contraction, thermal expansion, and thermal conductivity were determined.

Hundt, J.↗
NASA NTRS1980

Computational models for the nonlinear analysis of reinforced concrete plates

A finite element computational model for the nonlinear analysis of reinforced concrete solid, stiffened and cellular plates is briefly outlined. Typically, Mindlin elements are used to model the plates whereas eccentric Timoshenko elements are adopted to represent the beams. The layering technique, common in the analysis of reinforced concrete flexural systems, is incorporated in the model. The proposed model provides an inexpensive and reasonably accurate approach which can be extended for use with voided plates.

Hinton, E.↗
NASA NTRS1979

Glass fiber reinforced concrete for terrestrial photovoltaic arrays

The use of glass-fiber-reinforced concrete (GRC) as a low-cost structural substrate for terrestrial solar cell arrays is discussed. The properties and fabrication of glass-reinforced concrete structures are considered, and a preliminary design for a laminated solar cell assembly built on a GRC substrate is presented. A total cost for such a photovoltaic module, composed of a Korad acrylic plastic film front cover, an aluminum foil back cover, an ethylene/vinyl acetate pottant/adhesive and a cotton fabric electrical isolator in addition to the GRC substrate, of $9.42/sq m is projected, which is less than the $11.00/sq m cost goal set by the Department of Energy. Preliminary evaluations are concluded to have shown the design capabilities and cost effectiveness of GRC; however, its potential for automated mass production has yet to be evaluated.

Maxwell, H.↗
NASA NTRS1987

Molded Concrete Center Mine Wall

Proposed semiautomatic system forms concrete-foam wall along middle of coal-mine passage. Wall helps support roof and divides passage into two conduits needed for ventilation of coal face. Mobile mold and concrete-foam generator form sections of wall in place.

Lewis, E. V.↗
NASA NTRS1989

Concrete lunar base investigation

This paper presents results of structural analyses and a preliminary design of a precast, prestressed concrete lunar based subjected to one atmosphere internal pressure. The proposed infrastructure measures 120 ft in diameter and 72 ft in height, providing 33,000 sq ft of work area for scientific and industrial operations. Three loading conditions were considered in the design: (1) during construction; (2) under pressurization; and (3) during an air-leak scenario. A floating foundation, capable of rigid body rotation and translation as the lunar soil beneath it yields, was developed to support the infrastructure and to ensure the air-tightness of the system. Results reveal that it is feasible to use precast, prestressed concrete for construction of large lunar bases on the moon.

Lin, T. D.↗
NASA NTRS1989

Development of construction materials like concrete from lunar soils without water

The development of construction materials such as concrete from lunar soils without the use of water requires a different methodology than that used for conventional terrestrial concrete. A unique approach is attempted that utilizes factors such as initial vacuum and then cyclic loading to enhance the mechanical properties of dry materials similar to those available on the moon. The application of such factors is expected to allow reorientation, and coming together, of particles of the materials toward the maximum theoretical density. If such a density can provide deformation and strength properties for even a limited type of construction, the approach can have significant application potential, although other factors such as heat and chemicals may be needed for specific construction objectives.

Desai, Chandra S.↗
NASA NTRS1992

The possibility of concrete production on the Moon

When a long-term lunar base is constructed, most of the materials for the construction will be natural resources on the Moon, mainly for economic reasons. In terms of economy and exploiting natural resources, concrete would be the most suitable material for construction. This paper describes the possibility of concrete production on the Moon. The possible production methods are derived from the results of a series of experiments that were carried out taking two main environmental features, low gravity acceleration and vacuum, into consideration.

Ishikawa, Noboru↗
NASA NTRS1992

Concrete: Potential material for Space Station

To build a permanent orbiting space station in the next decade is NASA's most challenging and exciting undertaking. The space station will serve as a center for a vast number of scientific products. As a potential material for the space station, reinforced concrete was studied, which has many material and structural merits for the proposed space station. Its cost-effectiveness depends on the availability of lunar materials. With such materials, only 1 percent or less of the mass of a concrete space structure would have to be transported from earth.

Lin, T. D.↗
NASA NTRS1992

Properties and uses of concrete, appendix B

Concretes that can now be formed have properties which may make them valuable for lunar or space construction. These properties include high compressive strength, good flexural strength (when reinforced), and favorable responses to temperature extremes (even increased strength at low temperatures). These and other properties of concrete are discussed.

Corley, Gene↗
NASA NTRS1992

Concrete lunar base investigation

This paper presents results of structural analyses and a preliminary design of a precast, prestressed concrete lunar base subjected to 1-atm internal pressure. The proposed infrastructure measures 120 ft in diameter and 72 ft in height, providing 33,000 sq ft of work area for scientific and industrial operations. Three loading conditions were considered in the design (1) during construction, (2) under pressurization, and (3) during an air-leak scenario. A floating foundation, capable of rigid body rotation and translation as the lunar soil beneath it yields, was developed to support the infrastructure and to ensure the airtightness of the system. Results reveal that it is feasible to use precast, prestressed concrete for construction of large lunar bases on the Moon.

Lin, T. D.↗
NASA NTRS1995

The determination of the constitutive parameters of a medium with application to a reinforced concrete pad

This report describes the experimental and analytical efforts performed to determine the constitutive parameters of a reinforced concrete pad on which an aircraft (the NASA Boeing 757) was parked while its internal electromagnetic environment was measured. This concrete pad is part of the Large Electromagnetic System-Level Illuminator (LESLI) test facility at the Phillips Laboratory, Kirtland Air Force Base, New Mexico. The relative dielectric constant, conductivity, index of refraction, and reflection coefficient have been determined over the frequency range of 0 to 300 MHz and are presented.

Poggio, A. J.↗
NASA NTRS2005

Processes of Formation of Spheroidal Concretions and Inferences for "Blueberries" in Meridiani Planum Sediments

The MER Opportunity Athena Science team has described spheroidal hematite nodules in sediments at Meridiani Planum on Mars [1]. They were informally referred to as "Blueberries" in the initial press releases and for brevity that is the name to be used in this abstract. Not all spheroidal objects in sediments are nodular concretions, but this paper will discuss the diagenetic processes possibly relevant to understanding the origin of the Blueberries. There are many occurrences of spheroidal diagenetic concretions in terrestrial sediments and detailed work has been done to understand the processes of their formation. In particular, it is possible to reconstruct the controls on their shapes and compositions, both mineral and chemical. Although there may not be good analogs for the Meridiani Planum hematite spherules on Earth, it may be possible to deduce the former environmental conditions that led to their formation and whether they might retain (or even be) biosignatures.

Coleman, Max↗