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International Concrete Abstracts Portal

Showing 1-5 of 11 Abstracts search results

Document: 

SP32-02

Date: 

July 1, 1972

Author(s):

James C. Bailey and Ernest C. Clay

Publication:

Symposium Papers

Volume:

32

Abstract:

Automation in the block industry is at a primitive stage compared to some other industries. Within the block manufacturing process, the greatest advancement of automation has developed in proportioning and mixing. Those plants constructed in recent years that have been the most automated have all utilized single-stage autoclaving in some form. The efficiency of autoclave production depends on using a maximum portion of each 24 hr for curing, and a minimum I for loading and unloading the autoclave. Thus, efficient and b rapid movement of block from one end of the flow diagram to the other is important. It may be accomplished either by using transfer cars in a shuttle system or by using trains that operate over curved tracks and switches. Disadvantages of these systems suggest the desirability of a completely circular system if technical difficulties could be surmounted.

DOI:

10.14359/6598

Document: 

SP32-01

Date: 

July 1, 1972

Author(s):

George Verbeck and L. E. Copeland

Publication:

Symposium Papers

Volume:

32

Abstract:

The effect of temperature on the physical and chemical properties of hydrating cement is considered from the effect temperature has on both rate of hydration and on the composition of the hydration product. The increased rate of hydration produced by elevated temperature is discussed in terms of its apparent effect on the uniformity of distribution of the hydration product within the paste matrix and the significance of degree of uniformity of distribution on strength. The general chemical and physical nature of the hydration products formed below 212 F (1OOC) is essentially unaffected by curing temperature. In high pressure steam curing above 212 F the properties of the product can be considerably altered depening upon the temperature and the composition of the cement. The various phases produced for different temperatures and compositions are described in terms of the inherent nature of the basic calcium silicates. The strength of high pressure steam cured paste is shown to depend upon the phase composition of the product primarily through the influence fo the phase composition on its relative ability to reduce the capillary porosity of the paste.

DOI:

10.14359/6597

Document: 

SP32-10

Date: 

July 1, 1972

Author(s):

Clayton M. Crosier.

Publication:

Symposium Papers

Volume:

32

Abstract:

In connection with extensive laboratory investigations of auto-claved, foamed cellular concretes data have been secured on the effects of variations in the curing on the compressive strength and elasticity. The concretes were made of portland cement. Type I or III, with one of several Kansas pozzolanic materials, or with a fly ash used for comparison. In each of 53 laboratory batches, one curing factor was varied between the 2 or 3 sets of cylinders. This inves tigation covered the effects of each of the four curing variables (in order of extent of coverage): maximum autoclaving pressure, moist storage prior to autoclaving, duration of the maximum pressure, and rate of heating and cooling. The effects of each variable are found to be dependent on the properties of the pozzolan, especially fineness. For the proportions of volcanic ash used and the curing conditions studied, Type III cement was more effective than Type I, but for one fly ash the reverse was true. The analyses are discussed and tentative conclusions are summarized.

DOI:

10.14359/6606

Document: 

SP32-09

Date: 

July 1, 1972

Author(s):

C. James Gulde

Publication:

Symposium Papers

Volume:

32

Abstract:

of the materials used in autoclaved block and beick manufacutre contribute to the color, but piin ents contribute the most. Mineral pigments and some others are satisfactory, but all are not effective, and some contain undesirable contaminants. For many colors it is possible to duplicate, in masonry units, any combination of hue, value, and chroma. Versatility in color production and reproduction requires a simple color laboratory and the es-tablishment of a library of color specimens made with the masonry ingredients used by the plant. One patented procedure is based on the introduction of a fluidized color mix onto one face of the machine mold box immediately before each filling of the mold box.

DOI:

10.14359/6605

Document: 

SP32-08

Date: 

July 1, 1972

Author(s):

Y. M. Butt, V. V. Timashev, and V. S. Bakshutov

Publication:

Symposium Papers

Volume:

32

Abstract:

The phase compositions and crystal forms of calcium silicate hydrates and calcium aluminate hydrates formed during autoclaving are dependent on temperature, pressure, stoichiometric relationships, and the concentration of Ca2+, Na+, K+, and li+ ions in solution. Most crystals and crystal aggregations are of a characteristic type. Some crystal intergrowth occurs, mainly interpenetration and agglomeration. Illustrations are shown.

DOI:

10.14359/6604

123

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