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TECHNICAL PAPER

40 40
Compressive strength (MPa) 25 Compressive Strength (MPa) 45
35
35
30
30
25
20
20
15
15
10
10
5
0
0 10 20 30 40 50 60 5 0 0 10 20 30 40 50 60
Exposure periods (Weeks) Exposure Periods (Weeks)
A-C A-G A-K A-D A-H A-L
S-C S-G S-K S-D S-H S-L
Figure 12: Variation of compressive strength due to acid and sulphate Figure 13: Variation of compressive strength due to acid and sulphate
attack of mix C, G, and K attack of mix D, H, and L

Figure 14: Microstructure of GPCT Figure 15: Microstructure of GPCA

fly ash that is sodium aluminium silicates and that enhance the 3. Compared to GPCT curing, the GPCA curing typically
process of polymerization. Figure 14 shows the bond between achieves 98 % of the compressive strength at 28 days.
fly ash particles and silicates it looks a spherical inorganic 4. The performance of CC under acid attack and sulphate
molecular compound structure. In Figure 15, the stable phases attack was lower than GPCT and GPCA.
are developed. OPC produce the heat in the internal body of
5. After 52 weeks of acid exposure, the average weight loss
geopolymer when react with water and that heat enhance the
of the GPCT, GPCA and CC specimens was 12.69, 17.07
process of polymerization. Fly ash reacts with silicates in the
and 28.89 respectively.
presence of internal heat which are released during hydration
process between OPC and water and form a crystalline structure. 6. In sulphate attack, after 52 weeks of exposure, the average
In this image it is found that the fly ash particles dissolved with weight loss of the GPCT, GPCA and CC specimens was
silicates and OPC and form a layered structure of geopolymer 0.84, 2.56 and 11.07 % respectively.
binder. 7. After 52 weeks of acid exposure, the residual average
strength of the GPCT, GPCA, and CC specimens was
6. CONCLUSSIONS 46.89, 36.71 and 25.65 %, respectively.

Following are the conclusions which are drawn on the basis of 8. After 52 weeks of sulphate exposure, the residual average
the results of experimental work. strength of the GPCT, GPCA, and CC specimens was
97.58, 96.49 and 92.58 %, respectively.
1. The compressive strength increases when increasing the
9. Geopolymer concrete with temperature curing and
quantity of fly ash in the mix.
geopolymer concrete with ambient curing offer 1.85
2. The GPCT with temperature curing produced higher times and 1.44 times greater resistance to acid attack,
strength than the GPCA with ambient curing. respectively, compared to cement concrete.

THE INDIAN CONCRETE JOURNAL | FEBRUARY 2026 75