*3.1.2 IOT geopolymer with fly ash, GGBS and slag sand composition*

**Table 6** presents the details of proportions made with IOT, fly ash, GGBS, and slag sand. The amount of fly ash and GGBS was kept constant as 15% in all the compositions. As seen in **Table 6**, IOT increased from 20% (GB1) to 40% (GB3). The Ca/Si ratio was increased and varied between 0.504 (GB-1) and 0.368 (GB-3). All these compositions were made with 8 M alkaline solutions. Similarly, another set of composition with 10 M alkaline solution was made. IOT varied from 20% (GB4)


**67**

**Figure 16.**

*SEM micrographs of composites with (A) GB1, (B) GB3, and (C) GB6.*

*Utilization of Iron Ore Mines Waste as Civil Construction Material through Geopolymer Reactions*

to 40% (GB6) with 10 M alkaline solution. The ratio of Si/Al varied between 11.32 (GB-4) and 12.00 (GB-6). The Ca/Si ratio varied between 0.502 (GB-4) and 0.366

The compressive strength versus Ca/Si ratio at different curing periods for the different compositions is shown in **Figure 14**. The general trend of increase

*DOI: http://dx.doi.org/10.5772/intechopen.81709*

**3.2 Results and discussion**

(GB-6).

**Figure 14.**

**Figure 15.**

*Compressive strength vs. Si/Al.*

*Compressive strength vs. Ca/Si.*

#### **Table 6.**

*Details of mix proportion with fly ash, GGBS, and slag sand.*

*Utilization of Iron Ore Mines Waste as Civil Construction Material through Geopolymer Reactions DOI: http://dx.doi.org/10.5772/intechopen.81709*

to 40% (GB6) with 10 M alkaline solution. The ratio of Si/Al varied between 11.32 (GB-4) and 12.00 (GB-6). The Ca/Si ratio varied between 0.502 (GB-4) and 0.366 (GB-6).

### **3.2 Results and discussion**

*Geopolymers and Other Geosynthetics*

*3.1.2 IOT geopolymer with fly ash, GGBS and slag sand composition*

10 (8 M)

*Details of mix proportion with fly ash, GGBS, and slag sand.*

*XRD patterns of (A) fly ash, (B) GGBS, (C) slag sand, and (D) IOT.*

**Table 6** presents the details of proportions made with IOT, fly ash, GGBS, and slag sand. The amount of fly ash and GGBS was kept constant as 15% in all the compositions. As seen in **Table 6**, IOT increased from 20% (GB1) to 40% (GB3). The Ca/Si ratio was increased and varied between 0.504 (GB-1) and 0.368 (GB-3). All these compositions were made with 8 M alkaline solutions. Similarly, another set of composition with 10 M alkaline solution was made. IOT varied from 20% (GB4)

**Sample designation GB1 GB2 GB3 GB4 GB5 GB6** IOT (%) 20 30 40 20 30 40 Slag sand (%) 40 30 20 40 30 20 Fly ash (%) 15 15 15 15 15 15 GGBS (%) 15 15 15 15 15 15

> 10 (8 M)

NaOH sol. (%) 2.04 2.04 2.04 1.8 1.8 1.8 Na2SiO3 sol. (%) 1.37 1.37 1.37 1.71 1.71 1.71 Extra water (%) 3.8 3.8 3.8 3.69 3.69 3.69 Si (mol) 0.767 0.730 0.693 0.770 0.733 0.696 Al (mol) 0.068 0.063 0.058 0.068 0.063 0.058 Si/Al (molar ratio) 11.279 11.587 11.948 11.324 11.635 12.000 Ca (mol) 0.387 0.321 0.255 0.387 0.321 0.255 Ca/Si (molar ratio) 0.504 0.439 0.368 0.502 0.438 0.366

10 (8 M)

10 (10 M)

10 (10 M)

10 (10 M)

**66**

**Table 6.**

**Figure 13.**

Alkaline sol. (concentration)

The compressive strength versus Ca/Si ratio at different curing periods for the different compositions is shown in **Figure 14**. The general trend of increase

**Figure 14.** *Compressive strength vs. Ca/Si.*

**Figure 15.** *Compressive strength vs. Si/Al.*

**Figure 16.** *SEM micrographs of composites with (A) GB1, (B) GB3, and (C) GB6.*

in compressive strength with increase in time period (7, 14, and 28d) is observed. However, with increase in the amount of IOT (from 20to 40%) there is a fall in compressive strength. It is observed that in all the different samples the Ca/Si decreases with increase in IOT content. This was further attributed to decrease in compressive strength of the brick specimens. Almost identical trends were observed for the specimens with 10 M solution. **Figure 15** shows the compressive strength behavior of the bricks and its relationship with Si/Al ratio. It will be observed that with increase in Si/Al ratio there is decrease in compressive strength.

**Figure 16** shows the SEM micrographs of different composites. The SEM micrograph of GB1 reveals the crystalline nature of the material with irregular distribution of shapeless particles. Crystalline nature of the material may positively influence the compressive strength. GB3 sample also exhibited shapeless structures with irregular distribution. The aggregation due to surface kinetics is more compared to GB1. Due to high concentration of NaOH, GB6 is highly aggregated with less number of independent particles. The compressive strength of GB3 was found to be less due to low calcium content, less concentration of sodium hydroxide and irregular distribution of particles with some degree of aggregation.
