I Cement

Verkieselung,/. silicification. verkiesen, v.t. gravel, ballast pyritize. verkitten, .i. cement, lute seal. 

I cement, high-alumina cement, CaS04.2H20, Ca(OH)2 and CaO [75]. 

Most often precast producers use finely ground cement such as ASTM Type III to obtain desired production cycles. The high water reduction and concomitant rapid strength gain afforded by the use of superplasticizers will enable the precast producer to change to the more economical Type I cement (Table 7.8). 

ASTM Type I cement ASTM Type III cement ... 

Hydroxycarboxylic acid water-reducing agent (ml 50 kg-i cement) 0 120... 

Slrubie. L.I. Cement Research Progress 199.I. American Ceramic Society. Westerville. OH. 1997. http //www.acers.org/... 

Clark used a modified IAEA dynamic leach simulation test to evaluate Ba(I03)2, Ag, Hg(I03)2 and Pb(IO3)2 in Portland type I cement as disposal forms for 1Z9I captured using the Iodox process. Of the iodates tested, 68(103)2 in cement was generally superior and gave the most consistent results some samples with Hg(I0o)2 and AgI03 loadings performed comparably. Of the coatings and additives tried, addition of butyl stearate proved the most effective and reduced the leach rate by a factor of three. 

The most widely used single component, calcium sulfoaluminate admixture, is composed of 30% CAS, 50% CaSO and 20% CaO with small amounts of glassy phase. Particle s3ize is coarser than that of Portland cement. Larger particle size ensures that the potential expansion due to hydration is extended over a period of time. Chemical and physical properties of the most widely used proprietary product, Denka CSA, are given in Table 6.10 [74], Other CSAs include mixtures of C ASH and 2 CS (monosulfate and gypsum) and mixtures of Type I cement, liigh-aiumina cement, CaSO, 2H O, Ca(OH) and CaO [75], 4 2... 

Type III High-early-strength (HES) cements are made from raw materials with a lime-to-silica ratio higher than that of Type I cement and are ground finer than Type I cements. They contain a higher proportion of calcium silicate than regular portland cements. 

Table I. Cement, Steel, and Sulfur Production in Various Countries (3)...

After the investigations on PCCs in modified shrinkage channels had not led to the expected results, the aim was to verify the gained findings by means of experiments on polymer-modified cement stones (Fig. 3). CEM I - cement stone recipes were used. The water requirement of the stone granulation as to its w/c ratio was taken into account. 

Boikova, A.I., "Cement Minerals of Complicated Composition," Seventh International Congress on the Chemistry of Cement, Paris, Vol. 2, Communications I, 1980, pp. 6-11. 

Source Adapted from CEN EN 14227-1, Hydraulically bound mixtures - Specifications - Part I Cement bound granular mixtures, Brussels CEN, 2013. With permission ( CEN). 

It is used when high early strength is needed. It is has more CjS than Type I cement and has been ground finer to provide a higher surface-to-volume ratio, both of which accelerate hydration. Strength gain is double that of Type I cement in the first 24 hours. 

Because it generates less heat during hydration than type II it is used for massive concrete construction where large heat generation could create issues such as in gravity dams. It contains about half the C,S and C,A and double the C,S of Type I cement. The C,A content must be maintained below 7 wt.%. 

It exhibits a high sulfate resistance, and hence special cement used when severe sulfate attack is possible principally in soils or groundwaters having a high sulfate content. It gains strength at a slower rate than Type I cement. High sulfate resistance is attributable to low C,A content. 

ASTM Type ASTM Designation Composition Fineness cmVg Compressive Strength % of Type I Cement ... 

Gupta, P., Chattegi, S., and Jeffery, J. W., Studies of the Effeets of Various Additives on the Hydration Reaction of Tricalcinm Alnminate, Part I Cement. Tech., 1 3-10 (1970), Part II Cement Tech., 3 21-26 (1970), Part IV Cement Tech., 4 63-68 (1973), Part V Cement Tech., 4 146-149 (1973)... 

Figure 9. The effect of CaCh on the heat development in four Type I cements.

Type I Cement Paste + 0.6% Superplasticizer Type V Cement Paste... 

The samples of HDF cement sheets were prepared at the Runcorn Heath ICI laboratories. The OPC used was a standard grade Type I cement powder produced by Blue Circle and the BAC was Secar 71 produced by Lafarge. 

Note 1—Attention is called to the feet that cements conforming to the requirements for all types may not be carried in stock in some areas. In advance of specifying the use of other than lype I cement, it should be determined whether the proposed type of cement is or can be made available. 

Gutteridge, W. A., and L. J. Parrott (1976). A study of the changes in weight, length and interplanar spacing induced by drying and rewetting synthetic CSH (I) . Cement and Concrete Research 6(3) 357-366. 

Figure 8.49 STEM-BF images of hydrated samples, (a) Inner (IP) and outer product (OP) regions of a paste of alite hydrated for 90 days at 20°C (w/c = 0.4) (b) inner and outer product region of a CEM I cement hydrated for 90 days at 20°C (w/c = 0.4).

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