The Effect Of Adding Silica Fuume On The Characteristics Of The Asphalt Mixture To The AC -WC Layer
The Effect of Adding Silica Fume on the Characteristics of the Asphalt Mixture to the AC-WC Layer
Introduction
Road pavement layers often suffer damage or failure before reaching the age of the plan, resulting in functional damage such as cracks and bumpy surfaces, or structural damage such as reducing road surfaces. To overcome this problem, various studies have been conducted to improve the performance of asphalt mixtures, one of which is by utilizing additional materials or modifiers, such as silica fume. Silica fume is a by-product of the production of silicon metal or ferrosilicon alloys, and it has been widely used as a cementitious material in concrete. However, its use in asphalt mixtures has been limited, and its effects on the characteristics of the asphalt mixture are not well understood.
This study aims to analyze the effect of the addition of silica fume on the AC-WC layer on the characteristics of the asphalt mixture. This study is focused on increasing stability and flow mixture of asphalt measured by Marshall, as well as reducing the potential depth of rutting using the Wheel Tracking Machine (WTM) in the laboratory.
Research Methodology
This study uses 92 asphalt mixture samples with variations in silica fume levels of 0%, 2%, 4%, 5%, 6%, and 8% of asphalt levels. The sample was divided into 36 samples for the Marshall test before the optimum asphalt content (KAO), 54 samples for the Marshall test after KAO, and 2 samples for the WTM test.
Results and Discussion
The results showed that the addition of silica fume with a content of 5% produced the most optimal asphalt mixture characteristics and meets the specifications of the Revised III Bina Marga in 2010. The following is a further analysis of the impact of the addition of silica fume:
Marshall Test
The addition of silica fume increases the stability value of asphalt mixture, indicating that the asphalt mixture becomes more rigid and resistant to deformation. This is a significant finding, as increased stability is essential for preventing damage due to recurring traffic loads.
- Increased stability: The addition of silica fume increases the stability value of asphalt mixture, indicating that the asphalt mixture becomes more rigid and resistant to deformation.
- Increased VIM (Voids in Aggregate Minerals): A higher VIM value indicates the air cavity in a smaller asphalt mixture, which means that the asphalt mixture is denser and has a stronger binding power.
- Increased VMA (Voids in Mineral Aggregate): Higher VMA shows a greater percentage of air cavity in the asphalt mixture, which is important to provide space for asphalt to fill empty space and increase the ability of asphalt to withstand loads.
WTM Test
The asphalt mixture with the addition of 5% fume silica indicates a lower total deformation speed compared to the asphalt mixture without the addition of silica fume. This shows that the asphalt mixture has a greater deformation resistance, which is essential for preventing damage due to recurring traffic loads.
- Reduction of total deformation speed: The asphalt mixture with the addition of 5% fume silica indicates a lower total deformation speed compared to the asphalt mixture without the addition of silica fume.
- Improved deformation resistance: The asphalt mixture with the addition of silica fume has a greater deformation resistance, which is essential for preventing damage due to recurring traffic loads.
Conclusion
The addition of silica fume with a content of 5% has a positive effect on the characteristics of the asphalt mixture in the AC-WC layer. The asphalt mixture with the addition of silica fume has a higher stability, VIM, and VMA, and has better deformation resistance. This proves that silica fume is an effective additive in improving the performance of the asphalt mixture and extending the service life of the road pavement layer.
Recommendation
- Further research needs to be done to study the effect of adding silica fume on the characteristics of the asphalt mixture in the long run.
- Field tests need to be done to validate the results of laboratory research and ensure that the addition of silica fume can improve the performance of the asphalt mixture significantly in the field.
- Further research is needed to determine the optimal levels of silica fume needed for various types of asphalt mixtures and road conditions.
Future Research Directions
The findings of this study suggest that silica fume can be used as an effective additive in improving the performance of asphalt mixtures. However, further research is needed to fully understand the effects of silica fume on the characteristics of asphalt mixtures. Some potential future research directions include:
- Long-term studies: Conducting long-term studies to evaluate the effects of silica fume on the characteristics of asphalt mixtures over an extended period.
- Field tests: Conducting field tests to validate the results of laboratory research and ensure that the addition of silica fume can improve the performance of asphalt mixtures significantly in the field.
- Optimization of silica fume levels: Determining the optimal levels of silica fume needed for various types of asphalt mixtures and road conditions.
By conducting further research in these areas, it is possible to fully understand the effects of silica fume on the characteristics of asphalt mixtures and to develop more effective and sustainable asphalt mixtures for road construction.
Frequently Asked Questions (FAQs) about the Effect of Adding Silica Fume on the Characteristics of the Asphalt Mixture to the AC-WC Layer
Q: What is silica fume and how is it used in asphalt mixtures?
A: Silica fume is a by-product of the production of silicon metal or ferrosilicon alloys. It is a highly reactive, fine powder that is used as a cementitious material in concrete. In asphalt mixtures, silica fume is added to improve the performance and durability of the mixture.
Q: What are the benefits of adding silica fume to asphalt mixtures?
A: The addition of silica fume to asphalt mixtures has been shown to improve the stability, flow, and deformation resistance of the mixture. It also helps to reduce the potential depth of rutting and improve the overall performance of the asphalt mixture.
Q: How does silica fume affect the stability of asphalt mixtures?
A: The addition of silica fume increases the stability value of asphalt mixtures, indicating that the mixture becomes more rigid and resistant to deformation. This is a significant finding, as increased stability is essential for preventing damage due to recurring traffic loads.
Q: How does silica fume affect the flow of asphalt mixtures?
A: The addition of silica fume increases the flow value of asphalt mixtures, indicating that the mixture becomes more flexible and able to withstand deformation. This is a significant finding, as increased flow is essential for preventing damage due to recurring traffic loads.
Q: How does silica fume affect the deformation resistance of asphalt mixtures?
A: The addition of silica fume improves the deformation resistance of asphalt mixtures, indicating that the mixture is able to withstand deformation and prevent damage due to recurring traffic loads.
Q: What are the optimal levels of silica fume for asphalt mixtures?
A: The optimal levels of silica fume for asphalt mixtures are still being researched and studied. However, the results of this study suggest that a content of 5% silica fume is optimal for improving the performance and durability of asphalt mixtures.
Q: Can silica fume be used in all types of asphalt mixtures?
A: No, silica fume is not suitable for all types of asphalt mixtures. It is most effective in mixtures with high asphalt content and is not recommended for mixtures with low asphalt content.
Q: How does silica fume affect the cost of asphalt mixtures?
A: The addition of silica fume to asphalt mixtures can increase the cost of the mixture. However, the benefits of improved performance and durability may outweigh the additional cost.
Q: What are the potential drawbacks of using silica fume in asphalt mixtures?
A: The potential drawbacks of using silica fume in asphalt mixtures include increased cost, potential for over-reactivity, and potential for reduced workability.
Q: Can silica fume be used in combination with other additives?
A: Yes, silica fume can be used in combination with other additives to improve the performance and durability of asphalt mixtures. However, the optimal levels and combinations of additives are still being researched and studied.
Q: What are the future research directions for silica fume in asphalt mixtures?
A: Future research directions for silica fume in asphalt mixtures include long-term studies, field tests, and optimization of silica fume levels.