Stabilizing Clayey Soil using plastic waste materials
Stabilizing Clayey Soil using plastic waste materials
Samenvatting
Most world governments are concerned with waste disposal. The large accumulation of these waste items is causing environmental and monetary issues. According to (Awuchi, 2019), the predicted average daily production of plastic waste is 15.4 billion pieces. Plastic waste is the most prevalent form of waste. These are the most often used material types in our daily lives. Massive amounts of plastic garbage are produced, including plastic bottles made of polyethylene terephthalate (PET), as well as plastic bags and carpets made of polypropylene (PP). Polyethylene products are widely regarded as the primary constituents of waste materials. Plastic has a negative impact on the environment and human health, despite its numerous benefits in daily life.
Due to the impossibility of eradicating plastics from the world, researchers have begun focusing on the plastic's potential uses to combat the issue. Utilizing the plastic by recycling it, using it to improve the soil's engineering capabilities, or creating goods that are entirely recyclable.
If construction has existed, the requirement of increasing the engineering properties of soil has been recognized.
The modern era of soil stabilization began during the 1960's and 70's when general shortages of aggregates and fuel resources forced engineers to consider alternatives to the conventional techniques of replacing poor soils at building sites with shipped-in aggregates that possessed more favorable engineering characteristics. Consequently, now is the optimal time for such techniques, as there are numerous projects around the world utilizing soil stabilization techniques, such as cement soil stabilization, to improve the soil's properties. One of these projects is the construction of a 185-kilometer highway connecting Cairo to Alexandria. This project employed cement soil stabilization, and it is now one of the top highways/ roads in Egypt.
This research will discuss the impact of plastic garbage, namely polyethylene terephthalate (PE) and polypropylene (PP), on clay soil.
Egypt has one of the warmest climates in the world, therefore lower temperatures might result in a slower growth of tensile strength, leading to an increase in cracks because the tensile stresses will more frequently surpass the tensile strength, whilst higher temperatures may have the reverse effect.
This study investigates the effect of using plastic waste as fibre-shaped waste materials on geotechnical properties of soils. Several standard geotechnical laboratory tests were performed in order to identify the effect of length and contents of fibres that are randomly distributed throughout the soil and its effect on pavement thickness, cost effectiveness of such technique compared to native soil and cement stabilized soil.
The soil used in this study was collected near lake Marriot in Alexandria, Egypt the sample is divided into four equal parts by removing two diagonally opposite parts and then mixing two remaining parts properly. The physical properties of the soil are shown in Table below; this soil is classified as clay soil according to the American Society for Testing and Materials (ASTM) with about 93% silt and clay.
The mixing of the soil:
For all tests, the adopted content of fibers was first manually mixed into the air-dried soil in small increments. Considerable care was taken to achieve homogeneous mixture during the mixing process.
Then, the required water was added
Considered aspects during the study:
Temperature of pavement and its effect of plastic being melted
Mechanisms and applicability of various stabilizing agents
Ecological impact of using plastic waste materials in the soil and cement particles (its effect on the micro-organisms)
Advantages of such technique/method
What happens to the plastic after the life cycle of the road (how to get rid of it)
Different plastic sizes need more investigation
Relationship of CBR and E-dynamics
prevention of expansion and contraction of plastic
Laboratory tests:
standard compaction test (proctor test)
unconfined compressive strength test
California Bearing Ratio test
and resilient modulus tests
Kenpave calculations:
Asphalt thickness estimation on different traffic loads
Cost estimation
Base layer thickness estimation (Using odemark method)
Stabilized vs unstabilized soil (in terms of thickness, reliability compared to traffic load)
Asphalt thickness clayey stabilized vs cement stabilized
Cost estimation for clayey stabilized soil vs cement stabilized
Conclusion
Stabilization significantly enhances the engineering qualities of soils, including their physical, mechanical, and strength properties. This research examined these qualities using an experimental laboratory test program on two distinct waste polymers often found in disposal bins, namely polyethylene and polypropylene. The following are the major findings drawn from this research described here:
1. Soil stabilization using fiber has a distinct tendency for UCS and Mr., as increasing the fiber content does not result in an ascending trend in UCS, however increasing the fiber content
resulted in an ascending trend in Mr. values. As a result, the optimal fiber content should be found for stabilization with fibers at the maximum UCS and Mr. values.
2. PE and PP could be utilized to improve the physical and mechanical qualities of soil materials used in engineering projects.
3. The length of the fiber had an influence on the strength attributes of the stabilized soil, as increased length resulted in increased strength. This may require more research to determine the optimal fiber length which results in the optimum strength qualities.
4. For road pavement design codes of practice that use the CBR and Mr. as design parameters, the fiber stabilization is cost-effective, and it can be used successfully for a sustainable road construction if compared with chemically stabilized soils. The stabilization with chemical agents is accompanied by carbon dioxide emission, while fiber stabilization is not; this is one of the advantages of fiber stabilization over chemical stabilization.
5. While increasing the fiber content increased the value of CBR and Mr, the optimal fiber content for UCS was between 1% and 2% for both PE and PP.
6. The Microplastics has a bad side effects on the micro-organisms in the soil but while has to do with if the land will be used for agriculture purposes where most of the impacts occur.
7. Clayey soil stabilized using plastic is very effective in terms of strength and cost however the long-term side effects of such method is still unknown so further research on how you can get rid of the plastic in the soil after the lifetime of the road needs further investigation
8. Cement soil stabilization is effective in terms of cost compared to unstabilized soil and effective is the ESALS 106 but not as effective as the soil stabilized with plastic fibers in the use
of highways with high loads i.e., heavy trucks (ESALS 107)
9. Plastic fiber content (PE 1cm length) reduces the thickness by 0.75cm, and 0.50 for the 2cm length of PE, while PP didn’t have a noticeable effect compared to the PE plastic.
Organisatie | HZ University of Applied Sciences |
Opleiding | Civiele Techniek |
Afdeling | Domein Technology, Water & Environment |
Partner | Leads, Alexandria, Egypte |
Datum | 2023-01-01 |
Type | Bachelor |
Taal | Engels |