• Journal of the Korean Society for Railway
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• v.12 no.2
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• pp.183-189
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• 2009

The track structure of Gyungbu High Speed Railway line from Daegu to Busan is concrete track. It has a very strict specification for residual settlement because of its rigid type structural characteristics. The residual settlement of it comes from the residual settlement of the subgrade and the ground. The residual settlement of railway subgrade composed of crushed rock and soil might be major parts of total residual settlement depending on the field compaction qualities. Therefore, it is a key to minimize the residual settlement of the subgrade for a successful concrete track construction. In this paper, total 31 large scale compaction tests were performed to understand the compaction behaviors of the crushed rock-soil mixture. The test specimens were constituted with soil, crushed shale and mudstone taken from two sites under construction. The compaction tests were performed with the variations of rock types, #4 sieve passing contents, maximum particle size, and moisture contents. The influence of those factors on maximum dry unit weights of crushed rock-soil mixture was evaluated.

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.1
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• pp.1854-1860
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• 1970

Results of this study on the influence of percent passing of No. 200 sieve on soil compaction are as follows; 1. The higher maximum dry density of soil is, the lower optimum moisture content is. Maximum dry density is highest value and optimum moisture content is the lowest value in twocases that percents of No. 200 sieve are 30% in soils of which percents retained on No. 10 sieve are 5% and 10% respectively. 2. Maximum dry density increases according as uniformity coefficient increase. Maximum dry density is the highest when uniformity coefficient is approximately 300 in soil of which maximum diameter is 4.76mm. 3. Maximum dry density has a tendency to become large according as value of Cu Caincrease. Correlation between maximum dry density and $Log_{10}$(CuCa) shows straight line. 4. Maximum dry density increases according as n increase and reaches the peak when n equal 0.35 in condition that the index of talbot formula n is less than 0.35 in soil of which maximum diameter is 4.76mm. 5. Maximum dry density has a tendency to increase according as value of Cg $(Cg=\frac{P_{50}^2}{P_{10}{\times}{P_{200}}$) decrease.

• International Journal of Highway Engineering
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• v.4 no.2 s.12
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• pp.9-18
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• 2002

The main distresses that influence pavement performance are rutting, fatigue cracking, and longitudinal roughness. Thus, it is important to analyze the factors that affect these three distresses, and to develop prediction models. In this paper, three distress prediction models were developed using DataPave program which stores data from a wide variety of pavement sections In the United States. Also, sensitivity studies were conducted to evaluate how the input variables impact on the distresses. The result of sensitivity study for the prediction model of rutting showed that asphalt content, air void, and optimum moisture content of subgrade were the major factors that affect rutting. The output of sensitivity study for the prediction model of fatigue cracking revealed that asphalt consistency, asphalt content, and air void were the most influential variables. The prediction model of longitudinal roughness indicated asphalt consistency, #200 passing percent of subgrade aggregate, and asphalt content were the factors that affect longitudinal roughness.