混合ポルトランドセメントの研究 (第10報)

抄録

On continuing the previous studies, the authors reported, in the present paper, the results of further studies on various points of mixed Portland cements. The brief summaries are abstracted from the original Japanese paper, as following:
(1) The admixtures, which were used in the present studies, have the following chemical compositions.
Table 1. Total Analysis of Admixtures
Table 2. Soluble Analysis of Admixtures by Testing with Solutions of 10% NaOH and 5% HCl
(2) Various samples of mixed Portland cements were prepared by mixing common Portland cement clinker and these admixtures in proportions 60:40 and 80:20, and grinding with 2-3% of gypsum to fine powders by a laboratory pot mill, of which the fineness were nearly equal to the commercial Portland cement, i.e., the percentage of residue on 4900meshes/cm² sieve being 2-3%. The physical properties and chemical compositions are shown in the following tables.
Table 3. Mixing Proportions, Physical Properties of Mixed Portland Cements
Table 4. Chemical Compositions of Mixed Portland Cements
(3) The strengths of 1:3-cement-mortars of these cements were tested by (a) the ordinary method of specifications of Portland cement and blast fu nace slag cement in Japanese Engineering Standards JES 28 and JES 29 with dry mortar, and (b) the modifies method proposed by G. Haegermann in Germany (Protokoll der Tagung des Vereins deutscher Portland-Zement-Fabrikanten, E. V., Sept. 1929, 35; Reports of New International Association for Testing Materials, Zuerich, 1931, 669) and M. Ros in Switzerland (Diskussionsberichte Nr. 1, Nr. 10 & Nr. 60, Eidgenoessische Materialpruefungsanstalt, Eidg. Tech, Hochschuele, Zuerich) with wet mortar. Their results are tabulated in the following table 5 and 6.
Table 5. Compressive Strength (Cd) and Tensile Strength (T) of 1:3-Dry Mortar Tested by Standard Method of Specifications JES 28 and JES 29
Table 6. Compressive Strength (Cw) and Bending Strength (B) of 1:3-Wet Mortar Tested by Modified Method of Haegermann or Ros
(4) Ratios between these various results of strength testes were calculated and discussed the relations of these ratios and the properties of mixed Portland cements. These ratios are tabulated in the following table 7. These results are very well coincided with those reported by Haegermann or Ros (loc. cit).
Table 7. Ratios of Various Sorts of Strengths of 1:3-Dry and Wet Mortars
(5) The authors are now further studying on various points of mixed Portland cements and their results will be hereafter reported in the journal.