Film-forming ability of flowable cement pastes and its application in mixture proportioning of pervious concrete

In this work, we used the concept of paste content ratios in the mixture proportioning design of pervious concrete so that the concrete paste content could be adjusted to satisfy the requirements of different engineering applications. We experimentally demonstrated that compressive strength is negatively correlated with the coefficient of permeability and positively correlated with the paste content ratio. The highest compressive strength achieved in this study was 340 kgf/cm2, whereas the highest permeability coefficient was 0.116 cm/s. Design graphs for flowability, compressive strength, and permeability coefficient of the concrete mixtures were also constructed to be used by engineering companies as reference data.

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Properties of Low Water/Cement Ratio and High Compressive Strength Pervious Concrete

Materials Science Forum ◽

10.4028/www.scientific.net/msf.932.136 ◽

2018 ◽

Vol 932 ◽

pp. 136-140

Author(s):

Mao Chieh Chi ◽

Jiang Jhy Chang ◽

Wei Chung Yeih

Keyword(s):

Compressive Strength ◽

Flexural Strength ◽

Water Permeability ◽

Permeability Coefficient ◽

Pervious Concrete ◽

Unit Weight ◽

Cement Pastes ◽

Cement Ratio ◽

Water Cement Ratio ◽

Water Permeability Coefficient

The purpose of this study is to discuss the properties of low water/cement ratio and high compressive strength pervious concrete. Two sizes of air-cooling electric arc furnace slag (EAFS), for the same size of 0.24 - 0.48 cm and 0.48 - 0.96 cm, were prepared as the coarse aggregates. Two water-to-cement ratios and three filled percentages (70, 80, and 90%) of voids by cement pastes were selected as variables. The unit weight, connected porosity, water permeability coefficient, compressive strength, and flexural strength of pervious concrete were conducted. Test results show that the pervious concrete with higher filled percentage of voids by cement paste has higher unit weight, compressive strength, and flexural strength and smaller connected porosity and water permeability coefficient. The lower the water/cement ratio and EAFS size, the superior the properties. At the water/cement ratio of 0.25, pervious concrete with EAFS size of 0.24 – 0.48 cm and 90% filled percentage of voids by cement pastes had the highest compressive strength of 35 MPa and flexural strength of 7 MPa.

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Clean Electron Microscope Substrate Films Used for Micrometeorite Collection and Study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100061847 ◽

1967 ◽

Vol 25 ◽

pp. 366-367

Author(s):

D. M. Davies ◽

R. Kemner ◽

E. F. Fullam

Keyword(s):

Thin Film ◽

Electron Microscope ◽

High Altitude ◽

Amyl Acetate ◽

Temperature Variations ◽

Film Forming ◽

Film Specimen ◽

Particulate Contaminants

All serious electron microscopists at one time or another have been concerned with the cleanliness and freedom from artifacts of thin film specimen support substrates. This is particularly important where there are relatively few particles of a sample to be found for study, as in the case of micrometeorite collections. For the deposition of such celestial garbage through the use of balloons, rockets, and aircraft, the thin film substrates must have not only all the attributes necessary for use in the electron microscope, but also be able to withstand rather wide temperature variations at high altitude, vibration and shock inherent in the collection vehicle's operation and occasionally an unscheduled violent landing.Nitrocellulose has been selected as a film forming material that meets these requirements yet lends itself to a relatively simple clean-up procedure to remove particulate contaminants. A 1% nitrocellulose solution is prepared by dissolving “Parlodion” in redistilled amyl acetate from which all moisture has been removed.

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A Freeze Shadow Technique for the Preparation of Soft Paint Latexes for Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100079097 ◽

1977 ◽

Vol 35 ◽

pp. 314-315

Author(s):

Earl R. Walter ◽

Glen H. Bryant

Keyword(s):

Sample Preparation ◽

High Vacuum ◽

Vacuum System ◽

Latex Particles ◽

New Methods ◽

Diffusion Pump ◽

Film Forming ◽

Routine Basis ◽

Distribution Studies ◽

Preparation Techniques

With the development of soft, film forming latexes for use in paints and other coatings applications, it became desirable to develop new methods of sample preparation for latex particle size distribution studies with the electron microscope. Conventional latex sample preparation techniques were inadequate due to the pronounced tendency of these new soft latex particles to distort, flatten and fuse on the substrate when they dried. In order to avoid these complications and obtain electron micrographs of undistorted latex particles of soft resins, a freeze-dry, cold shadowing technique was developed. The method has now been used in our laboratory on a routine basis for several years.The cold shadowing is done in a specially constructed vacuum system, having a conventional mechanical fore pump and oil diffusion pump supplying vacuum. The system incorporates bellows type high vacuum valves to permit a prepump cycle and opening of the shadowing chamber without shutting down the oil diffusion pump. A baffeled sorption trap isolates the shadowing chamber from the pumps.

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