1:45 PM - 3:15 PM
[O11-P82] Create an Accurate and Simple Method for Evaluating Plasticity of China Clay
-Thinking about Soil Scientifically-
Keywords:Forest, Sagano High School Woods for Field Studies, Soil Texture, Clay Minerals, Japanese Industrial Standards
Abstract
We have been aiming to make “Sagano Yaki” by using the weathered rock layer of Sagano High School Woods for Field Studies (SWFS). The conditions for good pottery clay include moderate water absorbency, plasticity, viscosity, high-temperature durability, etc. (Taniguchi et al., 2024). X-ray diffraction results have revealed that the soil of SWFS contains clay minerals such as illite and vermiculite, which are 2:1 type layered silicate minerals (Okubo, 2017). In addition, the clay of SWFS is a unique red pottery clay, but it is considered difficult for amateurs to handle because it contains coarse sand fractions and has little silt fraction (Taniguchi, 2024).
Ijiri (2024) and Tanabe (2024) adopted the Atterberg method (Japanese Industrial Standards) to evaluate the plasticity of clay. However, the evaluation took a long time and gave negative values, making it difficult to get accurate results. They reported that a new analytical method is needed.
In this study, I aimed to develop a method to easily and quickly evaluate the plasticity of china clay.
1. Introduction
We have been aiming to make “Sagano Yaki” using the weathered rock layer of the Sagano High School Woods for Field Studies (SWFS). Good pottery clay requires moderate water absorbency, plasticity, stickiness, and high heat resistance (Taniguchi et al., 2024).
X-ray diffraction has shown that SWFS soil contains clay minerals like vermiculite and illite, which are 2:1 type layered silicates (Okubo, 2017). Although SWFS clay has a unique reddish color, it has been considered hard to work with because of its coarse sand content and lack of silt (Taniguchi, 2024).
Ijiri (2024) and Tanabe (2024) used the Atterberg method (a Japanese Industrial Standard) to measure plasticity, but they found it took too long and sometimes produced negative values. Therefore, a new, easier analysis method is needed. In this study, I aimed to develop a simple and fast method for evaluating clay plasticity.
2. Theory and Experiment
The samples used were commercially available red clay, white clay, and mogusa clay. For comparison, I also used montmorillonite and kaolinite, which are sold as reagents.
To evaluate the physical properties of the clay, I measured the plasticity index, Ip (the moisture content at which the sample becomes plastic), and the consistency index, Ic (a value that shows the sample’s hardness and stability) (Taniguchi, 2024).
For plasticity evaluation, I propose a new method using a 10 ml thermo syringe that can vertically push out clay under constant pressure, inspired by the use of capillary viscometers. I call this the RN-type cylinder method.
To avoid air bubbles, I filled the syringe carefully. I stood the piston vertically, then slowly placed a weight on it to push out the sample. When a small amount came out, I measured its moisture content using a heated moisture meter (MX50P1063203 by AND Co., Ltd.). I repeated this three times and used the average value.
The weight was between 1–5 kg. For comparison, I also used the Atterberg method and the Pfefferkorn method.
3. Results and Discussion
Using the Atterberg and Pfefferkorn methods, plasticity was highest in the order: red clay, mogusa clay, and white clay. Each sample took about one hour to measure.
In contrast, the RN-type cylinder method showed plasticity in the order: mogusa clay, white clay, and gave results in about one-third the time.
Graphs of weight vs. moisture content for mogusa and white clay showed almost linear relationships. However, for red clay, moisture content didn’t change much even when the weight changed, making it difficult to measure. This may be because red clay contains a lot of iron ions, like lepidocrocite.
Montmorillonite contains interlayer water, so the heat-drying moisture meter couldn’t remove all the water, making accurate moisture measurement difficult. Kaolinite, on the other hand, had the smallest moisture error among the clays, suggesting the RN-type cylinder method was accurate in this case.
4. Conclusion
The plasticity values of mogusa clay and white clay were similar between the conventional methods and the RN-type cylinder method, so the RN method appears to be sufficient for evaluating plasticity.
Also, since the plasticity ranking didn’t change regardless of the weight used, the method seems to have a wide range of applicability.
In the future, I hope to apply the RN-type cylinder method to evaluate the plasticity of soil from the school forest.
We have been aiming to make “Sagano Yaki” by using the weathered rock layer of Sagano High School Woods for Field Studies (SWFS). The conditions for good pottery clay include moderate water absorbency, plasticity, viscosity, high-temperature durability, etc. (Taniguchi et al., 2024). X-ray diffraction results have revealed that the soil of SWFS contains clay minerals such as illite and vermiculite, which are 2:1 type layered silicate minerals (Okubo, 2017). In addition, the clay of SWFS is a unique red pottery clay, but it is considered difficult for amateurs to handle because it contains coarse sand fractions and has little silt fraction (Taniguchi, 2024).
Ijiri (2024) and Tanabe (2024) adopted the Atterberg method (Japanese Industrial Standards) to evaluate the plasticity of clay. However, the evaluation took a long time and gave negative values, making it difficult to get accurate results. They reported that a new analytical method is needed.
In this study, I aimed to develop a method to easily and quickly evaluate the plasticity of china clay.
1. Introduction
We have been aiming to make “Sagano Yaki” using the weathered rock layer of the Sagano High School Woods for Field Studies (SWFS). Good pottery clay requires moderate water absorbency, plasticity, stickiness, and high heat resistance (Taniguchi et al., 2024).
X-ray diffraction has shown that SWFS soil contains clay minerals like vermiculite and illite, which are 2:1 type layered silicates (Okubo, 2017). Although SWFS clay has a unique reddish color, it has been considered hard to work with because of its coarse sand content and lack of silt (Taniguchi, 2024).
Ijiri (2024) and Tanabe (2024) used the Atterberg method (a Japanese Industrial Standard) to measure plasticity, but they found it took too long and sometimes produced negative values. Therefore, a new, easier analysis method is needed. In this study, I aimed to develop a simple and fast method for evaluating clay plasticity.
2. Theory and Experiment
The samples used were commercially available red clay, white clay, and mogusa clay. For comparison, I also used montmorillonite and kaolinite, which are sold as reagents.
To evaluate the physical properties of the clay, I measured the plasticity index, Ip (the moisture content at which the sample becomes plastic), and the consistency index, Ic (a value that shows the sample’s hardness and stability) (Taniguchi, 2024).
For plasticity evaluation, I propose a new method using a 10 ml thermo syringe that can vertically push out clay under constant pressure, inspired by the use of capillary viscometers. I call this the RN-type cylinder method.
To avoid air bubbles, I filled the syringe carefully. I stood the piston vertically, then slowly placed a weight on it to push out the sample. When a small amount came out, I measured its moisture content using a heated moisture meter (MX50P1063203 by AND Co., Ltd.). I repeated this three times and used the average value.
The weight was between 1–5 kg. For comparison, I also used the Atterberg method and the Pfefferkorn method.
3. Results and Discussion
Using the Atterberg and Pfefferkorn methods, plasticity was highest in the order: red clay, mogusa clay, and white clay. Each sample took about one hour to measure.
In contrast, the RN-type cylinder method showed plasticity in the order: mogusa clay, white clay, and gave results in about one-third the time.
Graphs of weight vs. moisture content for mogusa and white clay showed almost linear relationships. However, for red clay, moisture content didn’t change much even when the weight changed, making it difficult to measure. This may be because red clay contains a lot of iron ions, like lepidocrocite.
Montmorillonite contains interlayer water, so the heat-drying moisture meter couldn’t remove all the water, making accurate moisture measurement difficult. Kaolinite, on the other hand, had the smallest moisture error among the clays, suggesting the RN-type cylinder method was accurate in this case.
4. Conclusion
The plasticity values of mogusa clay and white clay were similar between the conventional methods and the RN-type cylinder method, so the RN method appears to be sufficient for evaluating plasticity.
Also, since the plasticity ranking didn’t change regardless of the weight used, the method seems to have a wide range of applicability.
In the future, I hope to apply the RN-type cylinder method to evaluate the plasticity of soil from the school forest.