1. Tribhuvan University Kathmandu, Nepal
International Conference on TIM, 2012, Nepal
Synthesis and Characterization of Geopolymer from Various Types of Construction Wastes
Arvind Pathak, Ambar B. Rangu Magar, Dipak Paudel,
Rishi B. Bhandari and Vinay Kumar Jha
Central Department of Chemistry
Institute of Science and Technology
Tribhuvan University
Kathmandu, Nepal

2. International Conference on TIM, 2012, Nepal
Abstract
Construction wastes such as coal fly ash (CFA), demolished cement-sand-mixture (DCSM), demolished cement sand-concrete mixture (DCSCM), brick dust (BD) are rich sources of alumino-silicate and thus can be used as raw material for the synthesis of geopolymer.
Geopolymers have been synthesized from construction wastes using alkali and alkali-silicate as activators.
Geopolymerization can transform a wide range of alumino-silicate materials into building materials with excellent physicochemical properties such as fire, acid and earthquake resistant.
Geopolymers have been synthesized from CFA, DCSM, DCSCM and BD of compressive strength 41.9, 47.0, 45.5 and 60.0 MPa respectively.

3. International Conference on TIM, 2012, Nepal
Introduction
Geopolymer is a class of synthetic aluminosilicate materials. It has a number of potential uses in several areas but predominantly as replacement of cement. The name “GEOPOLYMER” was first given to these materials by Prof. John Davidovits in 1970.
The existence of geopolymer can be seen in Egypt’s famous Pyramids. Roman cement and small artifacts, which were previously thought to be stone, were made using the knowledge of geopolymer techniques.

4. Some Features of Geopolymer
International Conference on TIM, 2012, Nepal
Some Features of Geopolymer
Ceramics
Paver
Precast structural pipes
Concrete sleepers
Land slide stabilization
Hazardous waste encapsulation

5. Geopolymer and Portland cement
International Conference on TIM, 2012, Nepal
Geopolymer and Portland cement

6. Geopolymer and Portland cement
International Conference on TIM, 2012, Nepal
Geopolymer and Portland cement
Hardening of Portland cement (P.C.) through simple hydration of calcium silicate into calcium di-silicate hydrate and lime Ca(OH)2.
Hardening of Geopolymer resin (GP) through poly-condensation of potassium oligo-(sialate-siloxo) into potassium poly(sialate-siloxo) cross linked network.

7. Geopolymer and Portland cement
International Conference on TIM, 2012, Nepal
Geopolymer and Portland cement

8. International Conference on TIM, 2012, Nepal
Objectives
To synthesize geopolymer from the construction waste with comparable compressive strength like ordinary cement materials.
To reduce the CO2 emission in the atmosphere.
To reduce the disposal problem of construction wastes.

9. Basic Mechanism of Geopolymerization
International Conference on TIM, 2012, Nepal
Basic Mechanism of Geopolymerization
Geopolymer
Construction
Waste
Sodium Silicate
Sodium Hydroxide
Smaller particle size of construction waste, sodium silicate and higher content of alkali metals enhance the dissociation and dissolution of alumino-silicate and thereby the formation of geopolymer will have positive influence.

10. Geopolymer Structure International Conference on TIM, 2012, Nepal
Barboca et al., 2000

11. Compressive Strength and XRD Pattern Measurements
International Conference on TIM, 2012, Nepal
Compressive Strength and XRD Pattern Measurements
SLF 9 Load frame machine
Bruker, D8 Advance Diffractometer

12. XRD-Patterns International Conference on TIM, 2012, Nepal BD DCSCM
DCSM

13. Comp. Strength With NaOH Variation
International Conference on TIM, 2012, Nepal
Comp. Strength With NaOH Variation

14. Comp. Strength With Particle Size Variation
International Conference on TIM, 2012, Nepal

15. Comp. Strength With Na2SiO3/CW ratio
International Conference on TIM, 2012, Nepal
Comp. Strength With Na2SiO3/CW ratio

16. Comp. Strength With Curing Time Variation
International Conference on TIM, 2012, Nepal
Comp. Strength With Curing Time Variation

17. Characterization of Geopolymer Products
International Conference on TIM, 2012, Nepal
Characterization of Geopolymer Products

18. International Conference on TIM, 2012, Nepal
Conclusion
The most suitable raw material for the synthesis of geopolymer is brick-dust.
Geopolymeric products of compressive strength more than 40 MPa was obtained with all types of construction wastes. Furthermore, with brick dust geopolymer of 60 MPa was achieved
Thus Produced geopolymer can provide better alternate for ordinary cement.
This will solve the problem of disposal and hence Geopolymers could turn construction waste into wealth.

19. Acknowledgements International Conference on TIM, 2012, Nepal
Associate Prof. Dr. Vinay Kumar Jha, Central Department of Chemistry, Tribhuvan University.
Nepal Academy of Science and Technology (NAST) for Ph.D. Fellowship and financial support (Project 2067/68).
Central Material Testing Laboratory, Institute of Engineering (IOE), Pulchowk Campus, Tribhuvan University, Kathmandu.
Assoc. Prof. Dr. Lalu Prasad Paudel, Head of Central Dept. of Geology, T. U., Kirtipur, Kathmandu for his valuable help in X-Ray diffraction measurement of samples.
Central Department of Chemistry, Tribhuvan University for providing me the necessary facilities to carry out my Doctoral study.
Organizing Committee and TIM Conference-2012 Team.

20. THANK YOU