· Assessment of a new in-situ compaction test and optimizing the number of rolling times using the pressure of the Road Tire

Recently, the MLIT is widely using the i-Construction in the construction sites to improve productivity and provide support to workers. The JDC Corporation are working on improving the Towed Scraper (picture), which is used for soil compaction by the pressure applied when rolling and it is also used for digging hauls. In particular, the degree of compaction is used as an indicator to find the optimum number of roller passes over the soil.

Towed Scraper

  • Evaluation and optimization of the granulated blast furnace slag-natural sand mixture hardening properties

The granulated blast furnace slag is classified as a high permeable stiff material while mixed with water it shows a time dependent self-hardening behavior. It has been used as earth reinforcement technique in harbor construction projects, however, onshore utilization of slag material is limited. In order to prevent the significant drop of the hydraulic permeability as a result of early hardening of the crushed particles, the slag particles were mixed with sandy soil and subjected to various curing durations then the strength development of the adopted mixtures was evaluated.

  • Soft Soil improvement by use of palm leaves fibers

The use of natural fibers is getting common because of their effectiveness in the soil reinforcement.

Palm leaves are widely available and mainly considered as waste. In this research the fibers are prepared from the palm leaves and are added to the soil at different percentage and ratio. The evaluated parameters of the fiber reinforced soil are the settlement and shear strength for soil experiencing excessive settlement and the heave for expansive soil.


  • Deterioration characteristics of Cement Improved Sand in Short Term Focused on Difference of Cement Addition Amount and Curing Condition

In Japan, soft ground is widely formed especially in coastal areas. Therefore, in recent years, cement stabilization methods have been widely used as a ground improvement technique for soft ground. However, it was observed that seawater invasion has significant influence in the long term durability of cement improved sand. Therefore, development of cement improved sand that has high durability against seawater is needed.