Investigation on electrically conductive aggregates as grounding produced by carbon materials
Tengku Hafidatul Husna Binti Tengku Anuar,
Investigation on electrically conductive aggregates as grounding produced by carbon materials Tengku Hafidatul Husna Binti Tengku Anuar - xv, 118 pages : illustrations (some color) ; 30 cm. + 1-CD ROM.
Faculty of Civil Engineering Technology
Thesis (Master of Science) -- Universiti Malaysia Pahang Al Sultan - 2025
Include bibliographical reference
Electrical grounding is crucial for the safety operation of any electrical installation and structures. To obtain this, soil resistivity must be kept low to provide a path for lightning currents to flow to the earth. Generally, conductive material such as carbon is often used to reduce soil resistivity. Detailed understanding of the performance of carbon material as ground replacement is crucial to improve the performance of earth grounding system. In this study, several carbon-based materials were considered, namely commercially available Marconite, graphite, activated carbon (AC) and pyrolytic carbon (PyC) are tested as substitute materials for electrical grounding applications in a high resistivity soil. Both powder and aggregated form were prepared and tested. Electrically conductive aggregate comprised of Marconite, graphite, AC and PyC mixed with cement and sand were considered in aggregated form. Optimum carbon materials were determined for the preparation of the mix. Additionally, powdered of similar materials were also tested at different percentage of 1, 3, 5, 7 and 10%, respectively. The effect of carbon material on electrical performance is evaluated through a few tests. For powder, water retention curve (WRC) was established first to predict the changes in the water content using a chilled-mirror dew-point potentiometer. Similarly, water absorption test was conducted for 7, 14 and 28 days to determine the water content of aggregated specimens. Crushing strength test was also carried out for measuring the aggregate under a gradually applied compressive load. After each test, the change in the electrical resistivity for powder and aggregated specimens were measured using a 4-point electrode Wenner resistivity meter. The changes in the impulse breakdown voltage were measured following ‘Up and Down’ method. A lightning simulation was also carried out to evaluate the grounding performance on all specimens using a TERCO HV 9000 High Voltage apparatus. Test results indicated that carbon materials can be used in both powder and aggregate forms. For powder, an increase in water content decrease in electrical resistivity value. For instance, Marconite powder was found to be 0.01 Ω.m when water increased to 6%. Test results for aggregate showed that the water absorption, crushing strength and electrical resistivity of aggregate varied with time. The electrical resistivity of aggregates was found to be stabilized after approximately 14 days and decreased at 5.0% by volume after 28 days. The conductive aggregates including Marconite, graphite, AC, and PyC had electrical resistivity values of 1.534, 1.553, 1.560, and 1.571 Ω.m, water absorption of 10.92, 13.11, 25.09, and 16.28%, and crushing strengths of 8.96, 7.16, 5.28, and 0.88 N/mm2. However, mortar aggregate showed significantly greater resistivity value (12700 Ω.m), lower water absorption capacity (10.85%) but higher crushing strength of 11.75 N/mm2 than conductive aggregate. The breakdown voltage value for Marconite, graphite, AC and PyC aggregate exhibited 30.5, 29.8, 29.5 and 30.1 kV, respectively. The lightning simulation test is useful to identify the grounding performance. Test results revealed that electrically conductive aggregates containing Marconite performed better compared to other carbon-based material considered. Nevertheless, other material tested showed significant decrease in the soil resistivity. In light of these findings, it is noted that carbon compounds be added either in aggregated or powder form to soil in order to improve soil grounding in problematic locations.
THE0010381 (Local)
Faculty of Civil Engineering Technology--Dissertations
Universities and colleges--Dissertations
Theses--Dissertations
Investigation on electrically conductive aggregates as grounding produced by carbon materials Tengku Hafidatul Husna Binti Tengku Anuar - xv, 118 pages : illustrations (some color) ; 30 cm. + 1-CD ROM.
Faculty of Civil Engineering Technology
Thesis (Master of Science) -- Universiti Malaysia Pahang Al Sultan - 2025
Include bibliographical reference
Electrical grounding is crucial for the safety operation of any electrical installation and structures. To obtain this, soil resistivity must be kept low to provide a path for lightning currents to flow to the earth. Generally, conductive material such as carbon is often used to reduce soil resistivity. Detailed understanding of the performance of carbon material as ground replacement is crucial to improve the performance of earth grounding system. In this study, several carbon-based materials were considered, namely commercially available Marconite, graphite, activated carbon (AC) and pyrolytic carbon (PyC) are tested as substitute materials for electrical grounding applications in a high resistivity soil. Both powder and aggregated form were prepared and tested. Electrically conductive aggregate comprised of Marconite, graphite, AC and PyC mixed with cement and sand were considered in aggregated form. Optimum carbon materials were determined for the preparation of the mix. Additionally, powdered of similar materials were also tested at different percentage of 1, 3, 5, 7 and 10%, respectively. The effect of carbon material on electrical performance is evaluated through a few tests. For powder, water retention curve (WRC) was established first to predict the changes in the water content using a chilled-mirror dew-point potentiometer. Similarly, water absorption test was conducted for 7, 14 and 28 days to determine the water content of aggregated specimens. Crushing strength test was also carried out for measuring the aggregate under a gradually applied compressive load. After each test, the change in the electrical resistivity for powder and aggregated specimens were measured using a 4-point electrode Wenner resistivity meter. The changes in the impulse breakdown voltage were measured following ‘Up and Down’ method. A lightning simulation was also carried out to evaluate the grounding performance on all specimens using a TERCO HV 9000 High Voltage apparatus. Test results indicated that carbon materials can be used in both powder and aggregate forms. For powder, an increase in water content decrease in electrical resistivity value. For instance, Marconite powder was found to be 0.01 Ω.m when water increased to 6%. Test results for aggregate showed that the water absorption, crushing strength and electrical resistivity of aggregate varied with time. The electrical resistivity of aggregates was found to be stabilized after approximately 14 days and decreased at 5.0% by volume after 28 days. The conductive aggregates including Marconite, graphite, AC, and PyC had electrical resistivity values of 1.534, 1.553, 1.560, and 1.571 Ω.m, water absorption of 10.92, 13.11, 25.09, and 16.28%, and crushing strengths of 8.96, 7.16, 5.28, and 0.88 N/mm2. However, mortar aggregate showed significantly greater resistivity value (12700 Ω.m), lower water absorption capacity (10.85%) but higher crushing strength of 11.75 N/mm2 than conductive aggregate. The breakdown voltage value for Marconite, graphite, AC and PyC aggregate exhibited 30.5, 29.8, 29.5 and 30.1 kV, respectively. The lightning simulation test is useful to identify the grounding performance. Test results revealed that electrically conductive aggregates containing Marconite performed better compared to other carbon-based material considered. Nevertheless, other material tested showed significant decrease in the soil resistivity. In light of these findings, it is noted that carbon compounds be added either in aggregated or powder form to soil in order to improve soil grounding in problematic locations.
THE0010381 (Local)
Faculty of Civil Engineering Technology--Dissertations
Universities and colleges--Dissertations
Theses--Dissertations