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Determination of Water Content of Fresh Concrete Using a Microwave Oven

Author : M. Nagi

Publisher :

Page : 7 pages

File Size : 17,72 MB

Release : 1994

Category : Concrete

ISBN :

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Book Description

As part of the Strategic Highway Research Program (SHRP) contract, Optimization of Highway Concrete Technology, a microwave-oven method for measuring water content of as-delivered fresh concrete was evaluated. Water contents of a series of concrete mixes prepared in the laboratory were gravimetrically determined by drying the concrete in a microwave oven and comparing these measurements with water contents used for making these mixes. A relatively high-power microwave (900 W) equipped with a turntable to provide uniform drying was used. Mixes used in the study included conventional concrete mixes with three types of aggregates with low, moderate, and high water absorptions and mixes with silica fume, fly ash and latex. Field ruggedness of the procedure was verified by testing under actual field conditions at placements of bridge deck overlays and full-depth pavement repair sections.













Use of Microwave Oven to Determine Water Content of Fresh Concrete

Author : Edwin C. Roshore

Publisher :

Page : 32 pages

File Size : 35,80 MB

Release : 1973

Category : Concrete

ISBN :

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Book Description

The purpose of this study was to investigate an alternative procedure for determining the water content of fresh concrete to replace or provide an alternate to the method now used in evaluating concrete mixer performance. A series of laboratory tests was conducted in which a microwave oven was used in parallel with an electric hot plate. Mortar samples of known water content and mortar samples sieved from concrete mixtures were dried in the microwave oven and on the hot plate. Water content was calculated and the results obtained through use of the two methods were compared. The results obtained indicated that a microwave oven is satisfactory for use in determining the water content of mortar samples taken from fresh concrete for concrete mixer performance tests. On the basis of the tests conducted, it is recommended that the microwave oven be designated as an alternate drying apparatus in the method of test for evaluating concrete mixer performance. (Author).



Evaluation of the Troxler Model 4430 Water-Cement Gauge

Author : Highway Innovative Technology Evaluation Center (U.S.)

Publisher : ASCE Publications

Page : 60 pages

File Size : 42,87 MB

Release : 1996-01-01

Category : Technology & Engineering

ISBN : 9780784474044

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Book Description

Prepared by the Highway Innovative Technology Evaluation Center, a CERF Service Center. This report describes a HITEC evaluation designed to determine the basic capabilities and limitations of the Model 4430 gauge, manufactured by the Troxler Electronic Laboratories,Øfor use in quality control and quality assurance procedures for concrete construction. The ratio of water to cementitious materials in a concrete mix is recognized as a prime determinant of the strength and ultimate durability of the concrete. The Model 4430 Nuclear Water/Cement Ratio Gauge is designed to measure the water-to-cement ratio in fresh concrete sequentially. The evaluation was carried out in four phases: computer simulations, laboratory testing,precision and bias evaluation, and field demonstrations.