Testing methods of pozzolanas
Practical Action
Test equipment
The equipment required for the test is given below.
Laboratory mill
A small laboratory mill able to crush hard rocks to a size of 100μm is required. A
machine with a throughput of approximately 10kg/minute is suitable.
Mixing machine
A good quality domestic paddle mixer (used in food preparation) will serve the
purpose
(reference 7).
Laboratory burette
For measuring water quantities. 50cm3 capacity is sufficient.
Flow table
A flow table conforming to ASTM C230 - 68 should be available.
Mould
A mould which gives standard 25mm cubes which can be demoulded without
causing damage to the cubes is required.
Curing bath
A curing bath with thermostatic control and circulation pump (for even distribution of
water temperature) is required. Temperatures of 50oC should be achieved.
Testing machine
A strain controlled compression test machine is used capable of applying uniaxial
compression with a strain rate of mm/minute.
As mentioned earlier the test is purely for means of comparison and quality control and
therefore the test results should not be used for satisfying the legal requirements. As the
cube size is smaller than those stipulated in the Standards, the results tend to be of a higher
value.
References and resources
1. BS EN 196-5:1996, Methods of testing Cement. Pozzolanicity test for pozzolanic
cements, British Standards Institute, 389 Chiswick High Road, London, W4 4AL,.
2. IS:1727:1967, Indian Standard - Methods of Test for Pozzolanic Materials, Indian
Standards Institute, Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Dehli 2, India,
3. ASTM C311 - 77, Standard methods of sampling and testing fly ash or natural
pozzolanas for use as a mineral admixture in Portland cement concrete. Has been
updated; latest version dates from 2007. American Society for Testing and Materials,
100 Barr Harbor Drive, P O Box C700, West Conshohocken, PA 19428-2959, USA,
4. Allen, W. J., The evaluation and testing of volcanic pozzolana, Thesis, 1981.
5. Lea, F. M., The Chemistry of Cement and Concrete, Edward Arnold Publishers Ltd.,
1937 (Reprinted 1970). Extensively revised and republished as – Hewlett P C (ed.),
Lea’s Chemistry of Cement and Concrete (4th Ed), A Butterworth-Heinemann, 2003.
6. Sybertz, F., Comparisons of different methods of testing the Pozzolanic activity of fly
ashes, from the Proceedings of the Third International Conference on Fly Ash, Silica
Fume and Natural Pozzolans in Concrete, Trondheim, Norway, 1989, American
Conference Institute, Detroit,1989.
7. Spence, R., and Allen, W. J., Lime Pozzolana Cements; testing and small scale
production, The Martin Centre for Architectural and urban Studies, Building
technical File, Number 28, 1990.
8. Also useful could be; Cement – Test Methods – Pozzolanicity Test for Pozzolanic
Cements, ISO (International Organization for Standardization) 863: 2008, ISO,
Geneva, Switzerland
9