This topic is very relevant to our current world because there is still no sure solution for the storage of radioactive material. Geopolymer Sample Mixture for Sulfuric Acid Test Mass Changes of Geopolymers Samples Curing at 26°C Mass Changes of Geopolymers Samples Curing at 60°C Result for the Compression Test. Geopolymer sample mixture for sodium sulfate test Mass changes of geopolymer samples Curing at 26°C Mass changes of geopolymer samples Curing at 60°C Result for the compression test.
Geopolymer sample without submerged sulfuric acid Geopolymer sample (8M) after submerged sulfuric acid Geopolymer sample (12M) after submerged sulfuric acid. Geopolymer sample without immersion in sulfuric acid Geopolymer sample (8M) after immersion in sulfuric acid Geopolymer sample (10M) after immersion in sulfuric acid. VPFESEM magnified Geopolymer sample (8M NaOH) VPFESEM magnified Geopolymer sample (12M NaOH) VPFESEM magnified Geopolymer sample (8M NaOH) VPFESEM magnified Geopolymer sample (12M NaOH) Graph of mass changes vs number of days of different sample of geopolymer immersed in sulfuric acid ( Hardens at 26℃).
INTRODUCTION
- Background
- Problem Statement
- Objective
- The Relevancy of the project
- Feasibility of the project
The experiment is to be conducted to confirm that the marketed cements known as Portland cements are greatly affected by the acidic medium. This waste can also have a number of other bad effects on geopolymers that will be studied further in this project. To achieve this goal, many experiments and tests must be conducted to ensure that this geopolymer is truly suitable for use as hazardous waste storage.
Analysis must also be performed after each test and evaluate whether the geopolymer sample is safe and passes the test to be used in industry. There are a number of experiments that will be run such as tests on sulfuric acid, tests on sodium sulphate and also water absorption. The equipment and tools needed to carry out the experiment are all available and provided, so there won't be much trouble in completing the project if the author follows the date line of the Gantt chart accordingly.
LITERATURE REVIEW
- Classification of Radioactive Waste
- Geopolymer
- Factors Affecting the Properties of Geopolymers
- Advantages of Geopolymer Cements
- Application of Geopolymer in Present Industry
- Acid Sulfate Soils
- Resistant of Geopolymer to Chemical
- Water Absorption on Geopolymer
The chemical composition of geopolymer material is similar to natural zeolitic materials, but the microstructure is amorphous instead of crystalline[3]. The polymerization process involves an essentially rapid chemical reaction under alkaline conditions on Si-Al minerals, resulting in a three-dimensional polymer chain reaction and ring structure composed of Si-O-Al-O bonds, as follows. Davidovits (1999) proposed the possible applications of geopolymers depending on the molar ratio of Si to Al, as given in Table 1.1. However, they also stated that curing at too high a temperature caused cracking and a negative effect on material properties.
Finally, they suggested the use of mild hardening to improve the physical properties of the material.[5] In another study, van Jaarsveld et al (2003) stated that the source materials determine the properties of geopolymers, particularly the CaO content and water-to-fly ash ratio.[7] Based on a statistical study of the influence of parameters on the polymerization process of metakaolin-based geopolymers, Barbosa et al reported the importance of the molar composition of the oxides present in the mixture and the water content. Low-temperature geopolymer hardening (L.T.G.S.) takes place at drying temperatures (50°C to 250°C), in alkaline conditions, via the oligosialate precursor (-Si-O-Al-O-) (Na) in concentrations from 2 to 6% of the ceramic weight pastes.
Tests were conducted to study the sulfate resistance of the calcium-based fly ash polymer and the normal commercial concrete. 13] The damage to the surface of the samples increased as the concentration of the acid solution increased. According to Olivia, et al, (2008), the fly ash geopolymer contains a higher proportion of pores in the mesopore size and this condition can cause water to penetrate easily and affect the durability of the material.
Mf = mass of the sample after immersion in water (grams) Mi = mass of the sample after the curing phase (grams). Most of the test was done only on weight loss in the geopolymer. The method that can be used is by using simple titration on the final dissolved water sample.
This finding could help improve the composition of the geopolymer, making it more vulnerable to water.
METHODOLOGY
- Flow Chart
- Gantt Chart
- Raw Materials and Chemicals Needed
- Research Procedure
In the experiments to be carried out, more raw materials and chemicals are needed. Repeat step 1 until step 5 by manipulating the concentration of sodium hydroxide (NaoH) solution with 10M and 8M. Finally, repeat steps 1 to 6 by curing the sample inside the oven with a set temperature of 60OC (oven).
Weigh and record the mass of the immersed sample at 2 day intervals until day 8. Prepare the geopolymer using the raw materials which are fly ash, sodium hydroxide (alkaline liquid) and water in the right ratio. Record the final mass of the sample and compare it to the initial mass.
Prepare geopolymer samples using raw material which is fly ash, sodium hydroxide (alkaline liquid) and water in proper ratio. After preparing the samples, prepare 3 basins and fill them with sulfuric acid solution respectively. Record the final mass of the samples and compare the value with the original mass.
Repeat step 1 to step 6 by replacing the sample with a batch curing at 60°C (oven).
RESULT AND DISCUSSION
Water Absorption Test
According to the graph below, samples with a curing temperature of 26ºC (sample A and sample B) show the same pattern. The structure of both geopolymer samples is not sufficiently hard and still tends to soften and dissolve when immersed in the basin filled with water. Meanwhile, samples with a curing temperature of 60ºC, sample A, sample B and sample C, also show the same pattern.
The mass of all three samples continues to increase gradually until 8 days of experiment, except sample E in which the mass of the geopolymer sample decreases. The comparison between samples with a high curing temperature can of course be determined by calculating the percentage of water absorption. Sample E shows the highest percentage of water absorption because it has a higher water content and this will lead to a higher porosity.
Sulphuric Acid Test
- Mass Changes
- Compressive Strength Test
- Characterisation of Geopolymer Fly-Ashes
Below are two separate graphs showing the comparison of the mass changes of all geopolymer samples at a curing temperature of 26°C and 60°C respectively. Based on the graphs and the calculation of the different percentages, it shows two different patterns between two geopolymer samples curing at 26 ℃ and 60 ℃. The geopolymer samples cured at 26℃ show a mass reduction after immersion in the sulfuric acid.
This pattern is completely opposite by the samples curing at 60℃, where their mass increases after exposure to acid. The samples with higher NaOH concentration tend to increase more mass compared to samples with lower concentration. The visual appearance of the samples after being immersed in sulfuric acid solution after 56 days showed that the acid attack slightly damaged the surface of the samples.
The images below compare the visual appearance of geopolymer samples after immersion with acid and a sample without. The damage to the sample surface increases as the concentration of NaOH for geopolymer mixing decreases. Based on Figure 4.11, the graph shows that the geopolymer samples cured at 60 °C are much stronger and can withstand more load compared to the samples cured at 26 °C.
The sample can increase its hardness by mixing fly ash with higher concentration of NaOH. Curing at higher temperature with high concentration of NaOH can help to form a hard structure and make the sample denser compared to samples that are cured at 26°C and lower concentration of NaOH. The main purpose of this test is to look more closely at the structure and properties of the samples.
The images below show the test results, and based on the images we can make a comparison between the samples curing at 60°C and 26°C. Consequently, it causes samples cured at 26 °C to have a lower compressive strength compared to samples cured at 60 °C. Crystals also begin to form in samples that solidify at 60 °C. These numbers also show that not all samples are well mixed, as a round shape the size of fly ash can be seen.
Sodium Sulphate Test
- Mass Changes
- Compressive Strength Test
The value for both graphs above is taken from the mean value of the respective sample group. Geopolymer specimens cured at 60℃ show an increase in mass after immersion in sulfuric acid, which is completely opposite to the sample cured at 26℃. Samples cured at 60℃ tend to absorb and absorb more solution and meanwhile samples cured at 26℃ are not resistant to acid attack.
The reason for this result is that a sample that solidifies at a higher temperature will have a better completion of the reaction. Based on the result, it can also be seen that the mixtures with lower concentration of NaOH tend to lose more mass compared to the mixture with higher concentration of NaOH. This is mainly due to the high concentration of NaOH, which makes the structure harder and denser, so the geopolymer can withstand acid attack.
After immersing the geopolymer samples in a basin filled with sodium sulfate with 5% concentration for 56 days, all these specimens should undergo their compressive test using the 3000KN compression machine. After recording the entire compression reading for all the geopolymer specimens, comparison was made by drawing a line graph. Based on Figure 4.26, the graph shows that geopolymer samples cured at 60°C are much stronger and can withstand more stress compared to samples cured at 26°C.
This pattern is approximately the same for samples immersed in sulfuric acid.
CONCLUSION
![FIGURE 2.2: Manufacture of fire-resistant wood-chipboards faced with geopolymer (Na-Poly(sialate) [10]](https://thumb-ap.123doks.com/thumbv2/azpdforg/10278112.0/21.892.216.788.431.639/figure-manufacture-resistant-chipboards-faced-geopolymer-poly-sialate.webp)
