1、CEMENT and CONCRETE RESEARCH. Vol. 9, pp. 319-324, 1979. Printed in the U.S.A. 0008-8846/79/030319-06502.00/0 Copyright (c) 1979 Pergamon Press, Ltd. ON THE DISSOLUTION OF THE INTERSTITIAL PHASES IN PORTLAND CEMENT W. A. Gutteridge Cement and Concrete Association, R 9g of cement are added to this so
2、lution and stirred for one minute, after which time the solution is filtered and the residue washed in 50 ml of water followed by A B C FIG. i Diffractive pattern of an OPC Clinker (ES 1925) a) As received b) Residue after a KOSH treatment c) Residue after a KOSH treatment followed by 30 minutes in
3、a 2g : 30 ml SAM solution. I I-A Kol FIG. 2 Diffraction pattern of a synthetic beta dicalcium silicate Vol. 9, No. 3 321 DISSOLUTION, CEMENT, INTERSTITIAL PHASES 100 ml of methanol and dried at 60C. Nothing will be gained by leaving the cement in the KOSH solution for longer than one minute as the l
4、iquid will become more difficult to filter. The effect of the treatment in the KOSH solution is shown in Figure 1, where Figure l(a) is the diffraction pattern of an O.P.C. clinker (reference number ES 1925) in its as-received condition and Figure l(b) is the diffraction pattern of the clinker after
5、 one minute in a KOSH solution at 95C, showing that the interstitial phases have been removed. 2. Dissolution of the alite and belite hases Hjorth and Lauren () confirmed Takashimals suggestion () that the alite and belite in Portland cement will dissolve at different rates in a solution of salicyli
6、c acid in methanol. They prepared two residues from 5g samples of a ground cement clinker to which O.25g of futile had been added. One residue, obtained after stirring the sample of clinker and rutile for 2 hours in a solution of 2Og salicylic acid in 300 ml of methanol (4) contained interstitial ph
7、ases periclase and futile. The other residue contained the dicalcium silicate phase as well as the interstitial phases, periclase and rutile and was obtained using Hjorth and Laurens technique. In this they suggest that the concentration of the salicylic acid methanol solution required to dissolve t
8、he alite completely in 2 hours could be estimated using the Bogue potential compound composition. For a 5g sample of ground cement clinker the weight of salicylic acid per 300 ml methanol 32 would be five times the S content of 3.0 the clinker as given by the Bogue 2.e potential compound composition
9、. X-ray 0 2-6 intensity data collected from these s residues were processed by a computer 2.4 to give the X-ray diffraction pattern 2-2 for the dicalcium silicate phase. This 2.0 method of using a salicylic acid - 1.8 methanol (SAM) solution has been found to be very effective in dissolving 16 prefe
10、rentially the alite phase contained I 14 in a residue obtained from a KOSH 1.2 solution treatment. It has been shown 1.0 that the dissolution time can be 3 reduced to 30 minutes and a residue rich i 08 in dicalcium silicate can be obtained o 0e using one of the following procedures. 0-2 I I I I I I
11、I i 2 4 6 8 10 12 14 16 18 20 22 24 Grams of Salicylic Acid per 30Orals of methanol 0.4 FIG. 3 Relationship between the amount of alite dissolved from O.P.C. clinker ES 1925 and the concentration of a Salicylic acid/mothanol solution (in 30 minutes). in this notation C -= CaO and S - Si 322 Vol. 9,
12、No. 3 W.A. Gutteridge 4 = . *a“ 1.0 Z o.e .;|o., |o.4 I=E IIII &O.2 0 2 4 6 8 10 12 14 16 18 20 22 OCtlml of Salicylic Acid per 300 mls of methanol FIG. 4 Relationship between the amount of belite dissolved from 0.P.C. clinker ES 1925 and the concentration of a Salicylic acid/methanol solution (in 3
13、0 minutes). 2. a) When the comosition of the cement or clinker is known Figures 3 and 4 show the amount of alite and belite which can be removed from an O.P.C. clinker (reference number ES 1925) for various concentrations of SAM solution. These data were obtained using the quantitative X-ray diffrac
14、tion analysis technique employed at the Cement and Concrete Association. The composition of O.P.C. clinker ES 1925, determined by quantitative X-ray diffraction analysis is given in Table I. TABLE 1 Composition of clinker ES 1925 (in mass percent) Afire Belite Interstitial Material Periclase Free Li
15、me 51 36 11.5 0.5 1.0 A 5g sample of KOSH residue would contain therefore 2.9g (or 58 mass percent) alite and 2g (or 1 mass percent) belite. The data given in Figures 3 and indicate that the 2.9g of alite would dissolve in 3 minutes in a solution containing 20g of salicylic acid in 300 ml methanol.
16、At the same time approximately 1.&g of the 2g of belite would be dissolved. A reasonable yield was obtained from a 15g sample of KOSH residue which after filtration was washed in 250 ml of methanol and dried at 60C. Its diffraction pattern, shown in Figure 1(c) indicated that although a small quanti
17、ty of alite (at 51.7 degrees 2), periclase (at 2.8 degrees 2) and calcite (29. degrees 2) remained the residue was principally belite (see Figure 2). 2. b) When the comosition of the clinker or cement is not known Dissolution of the interstitial phases with a KOSH solution is now a part of the routi
18、ne procedure used at the Cement and Concrete Association in the preparation of cement for qualitative X-ray diffraction. In those instances when the diffraction pattern obtained from a KOSH residue indicates that a high temperature form of dicalcium silicate might be present in the residue, (see Fig
19、ure 5(b) ) it has been found convenient to use a three stage dissolution process. 1. Concentrate the dicalcium silicate phases in a 5g sample of the cement by using a SAM solution containing less than 12g of salicylic acid in 300 ml. Obtain in total 20 %o 30g of residue. 2. Use a more concentrated S
20、AM solution to remove as much of the alite as possible whilst leaving a reasonable amount of residue. Vol. 9, No. 3 323 DISSOLUTION, CEMENT, INTERSTITIAL PHASES A B m emlema |-A Kml C W FIG. 5 Diffraction patterns of O.P. Cement (ES 1259) a) As received b) Residue after a KOSH treatment c) Residue a
21、fter 30 mlnutes in a ig : 30 ml SAM solution followed by I0 minutes in a 14g:30 ml SAM solution and i minute in a KOSH solution. 3- Remove the interstitial phases from the concentrated residue using a KOSH solution treatment. When the concentrated residue contains a large quantity of interstitial ma
22、terial it is prudent to use the KOS solution treatment twice and be certain that the intelstitial phases have been removed. Figure 5(c) shows that X-ray diffraction pattern obtained from the residue of a Portland cement (reference number ES 1259) after this three stage dissolution process. The stron
23、g diffraction at 31 degrees 2e (0.288 nanometres) is due principally to delomite originally present as an impurity in the gypsum added to the coment clinker. Acknowl edgoment s The author wishes to thank Dr K Mather of the O.S. Army Engineers 9 Waterways Experimental Station, who kindly supplied the
24、 sample of cement (reference number ES 1259) used in this work. References 1. Proc. 3rd International Symposium on the “Chemistry of Cement“, 19521 Cement and Concrete Association. 2. W.A. Klein and J. Skalny, “Selective dissolution of clinker minerals and its applicationtW. Martin Marietta Laborato
25、ries, MML. TR 77-32, May 1977 pp 1-30. 3. L Hjorth and K-G Lauren, “Belite in Portlend cementvl Cement and Concrete Research, Vol 1, pp 27-0, 1971. 324 Vol. 9, No W.A. Gutteridge 2. Saburo Takashima, “Systematic dissolution of calcium silicate in commercial Portland cement by or0anic acid solution“. Review of the 12th General Meeting held in Tokyo, May 1958, Japan Cement Engineering Association, ppl2-13, Tokyo (1958).
