Tomoaki Satomi

A statistical study on the effect of water content, temperature and clay in soil reduction activity when processing contaminated recycled asphalt aggregate with screenless separation equipment with a vibration device

Waste asphalt blocks from construction sites are usually processed in the recycling plants to be used as recycled asphalt aggregates (RAA). At present, the RAA known as grizzly-under-materials (GUM) does not satisfy the required value for soil content, therefore it is used as roadbed materials. In 2009, a screenless piece of equipment was proposed to remove the soils from GUM, but it was necessary in 2013, to carry out a process of re-designing. This study shows a statistical analysis related to the effect of changing water content, temperature and clay, in soil reduction activity processing GUM with the newly screenless separation equipment. It was found that, from the point of view of statistics, difference arises in the equipment performance, when it was changed the soil contained in GUM and temperature, increasing the water content in the sample to process, besides, the highest difference was obtained changing soil, keeping constant temperature (15°C).

Study on Strength of Modified Sludge Produced By Fiber-Cement Stabilized Soil Method Using Several Kinds of Fiber Materials

In the South of Viet Nam, every year, a large amount of excavated sludge from construction sites has been disposed directly in the final disposal, but the recycling rate of sludge is low. Therefore, in this study, fiber-cement stabilized soil method was applied to recycle sludge in Viet Nam. Moreover, paper, rice straw, rice husk, and cornsilk were used as fiber materials in this method because they are waste materials and easily obtained in Viet Nam. Four kinds of fiber and cement were used to improve sludge and unconfined compression tests were carried out to collect failure strength and strain data. The experiments were performed under 28 mixing conditions. The water, fiber, and cement content were changed to find out which fiber material is the most suitable to modify sludge in Viet Nam. The results showed that rice straw gave the best results to modify sludge by using fiber-cement stabilized method.

Study on Effect of Cornsilk Fiber in Cemented Soil Stabilization

Fiber-cement stabilized soil is one of many methods for strengthening soil. However, the kind of fiber material used in this method plays an important role. So far, many researchers have studied on many kinds of fiber to stabilize soil such as rice straw, rice husk, pineapple leaf, banana leaf, etc. These fiber materials are abundant, cheap and easy to obtain from the agricultural field because most of them are discarded. Furthermore, the traditional way to dispose of agriculture waste is burning causing some environmental pollution problems. Therefore, the utilization and direct use of waste materials are of much benefit to environment and economy. Nowadays, corn is the third most cultivated crop in the world, so the by-product from corn such as cornsilk is redundant and easy to collect from the field. Hence, the present work aims to study the effect of new waste fiber material as raw cornsilk fiber in strengthening soil. This study uses the unconfined compressive test to evaluate the strength and strain of cemented soil and fiber-cemented soil. Soil used in this study is artificial soil, which is made of clay and silt with the ratio of 2:3, respectively. Cemented soil admixtures are made with cement contents of 30, 35, 40 kg/m3. The effect of fiber content is studied in this study by changing the fiber content added to cemented soil admixtures at different levels of 5, 10, 15, 20, 25, 30 kg/m3. The results of this study show that it is possible to utilize of cornsilk as fiber material in cemented soil stabilization.