By
Er. Kaushal Kishore ,
Materials Engineer, Roorkee
There is no direct method for the determination of Fly Ash content in the PPC. However, based on the past test results of insoluble Residue in the PPC, Fly Ash content in the supplied PPC may be obtained.
REAGETS
1. Hydrochloric acid – Sp gt 1.16 (conforming to IS : 265-1976)
2. Dilute Hydrochloric acid with distilled water 1:99 (by volume)
3. 2N Sodium Carbonate Solution.
DETERMINATION OF INSOLUBLE RESIDUE
The sample of the PPC shall be moisture free and taken as per requirements of IS : 3535-1966. The representative sample of the cement selected as above shall be thoroughly mixed before using.
Take one gram of the above PPC sample add 25 ml of cold water and while the mixture is stirred vigorously add 5 ml of hydrochloric acid, if necessary, head the solution and grind the material with flattened end of a glass rod until it is evident that the decomposition of the cement is complete. Dilute the solution to 50 ml and digest for 15 minutes at a temperature just below boiling. Filter and wash the residue thoroughly with hot water. The filter paper with the residue shall be proceeded for further test.
Digest the filter paper containing the residue in 30 ml of hot water and 30 ml of 2N sodium carbonate solution maintaining constant volume, the solution being held at just below the boiling point for 10 minutes. Filter and wash with dilute hydrochloric acid (1:99) and finally with hot water till the residue is free from chloride. Ignite the residue in a tarred crucible at 900 to 10000C, cool in a desicator and weight
From the figure the insoluble residue obtained from the above test, Fly Ash content in the supplied PPC may be obtained. Read references to conduct experiments and find conclusions.
REFERENCES
1. IS : 3535 – 1966 – Method of sampling hydraulic cements, BIS, New Delhi.
2. IS : 265-1976 – Specification for hydrochloric acid (second revision BIS, New Delhi)
3. IS : 4032 – 1985 – Method of chemical analysis of hydraulic cement (First Revision) BIS, New Delhi.
4. IS : 1489 (Part-I) : 1991- (Reaffirmed 2005) (Third Revision) Portland Pozzolana Cement – Part-I Fly Ash based BIS, New Delhi.
5. Nagele, E (1981) – Application of the flotation method to analytical problems of concrete technology Diss, Universitat Karlsruhe, FRG.
6. Hilsdorf, H.K., Nagele, E (1980) a new method for cement content determination of fresh concrete, Cem. Concr. Res. 10, 23-34.
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