• Magazine of the Korean Society of Agricultural Engineers
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• v.18 no.3
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• pp.4171-4183
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• 1976

This study is to investigate the effect of some physical properties of soil on the compaction. The compaction effect depends upon various factors such as soil type, moisture content, gradation and compaction energy. In this study, with steady compaction energy, the relationships between maximum dry density and moisture content, gradation and consistency were analyzed by soil types. Some results obtained in this study are summarized as follows 1. Generally, the coarser the grain size, the bigger is the maximum dry density and the smaller is the optimum moisture content and its moisture-dry denisty curve is relatively steep. The finner the grain size, the smaller is the max. dry density and the bigger is the opt. moisture content and its moisture-dry density curve is less steep. 2. The relationship between max. dry density (${\gamma}$dmax) and opt. moisture content, void ratio, clay content, percent passing of No. 200 sieve, liquid limit and plastic limit can be represented by the equation ${\gamma}$dmax =ao+a1X(a0>0, a1<0) 3. The relationship between opt. moisture content (Wopt) and clay content, percent passing of No. 200 sieve, liquid limit and plastic limit can be represented by the equation Wopt=a0+a1X(a0>0, al>0). 4. The fact that maximum dry density of the compacted soil is decreased with the increase of the optimum moisture content in any types of soil tested, and the fact that optimum moisture content can be positively correlated with clay content, percent passing of No. 200 sieve, liquid limit and plastic limit of the soil, lead to the conclusion that clay content, percent passing of No. 200 sieve, liquid limit and plastic limit of the soil are direct factors in reduction of the maximum dry density of engineering soil.

• Journal of the Korean Geosynthetics Society
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• v.17 no.1
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• pp.11-20
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• 2018

Surplus soil is commonly used at construction sites, because suitable fill material is not always immediately available and leads to additional costs. However, most surplus soils do not meet the requirement of suitable fill material to achieve the stability and strength of embankments. In this study, Proctor compaction tests and field compaction tests were performed by installing geosynthetics to resolve the problems caused by compacting unsuitable soils. Compaction energy and the number of geosynthetics were changed under the type A- and D- and type A Proctor compaction tests (KS F 2312), respectively. The field compaction testing using geosynthetics was performed on surplus soils of high water content. Optimum water content and maximum dry density of compacted soil decreased and increased by reinforcing geosynthetics, respectively. Compaction curves behaved with geosynthetics as the compaction curves behaved with higher compaction energy. Efficient compaction was possible because the compaction energy increased to 2.10 and 2.71 times the compaction energy required to achieve the same maximum dry density with one and two geosynthetic layer(s), respectively. Furthermore, field compaction tests verified that efficient compaction was possible because the dry density of unsuitable surplus soils of high water content was increased by reinforcing geosynthetics.

• Magazine of the Korean Society of Agricultural Engineers
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• v.21 no.2
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• pp.81-103
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• 1979

The weathered granite soil involves problems in its stability in soil structures depending upon the reduction of soil strength due to the water absorption, crushability, and content of colored mineral and feldspar. As an attemt to solve the problems associated with soil stability, the crushability of weathered granite soil was investigated by conducting tests such as compaction test, CBR test, unconfined compression test, direct shear test, triaxial compression test, and permeability test on the five soil samples different in weathering and mineral compositions. The experimental results are summarized as follows: The ratio of increasing dry density in the weathered granite soil was high as the compaction energy was low, while it was low as the compaction energy was increased. The unconfined compressive strength. and CBR value were highest in the dry side rather than in the soil with the optimum moisture content, when the soil was compacted by adjusting water content. However, the unconfined compressive strength of smples, which were compacted and oven dried, were highest in the wet side rather than in soil with the optimum moisture content. As the soil becomes coarse grain, the ratio of specific surface area increased due to increased crushability, and the increasing ratio of the specific surface area decreased as the compaction energy was increased. The highest ratio of grain crushability was attained in the wet side rather than in the soil with the optimum moisture content. Such tendency was transforming to the dry side as the compaction energy was increased. The effect of water on the grain crushability of soil was high in the coarse grained soil. The specific surface area of WK soil sample, when compacted under the condition of air dried and under the optimum moisture content, was constant regardless of the compaction energy. When the weathered granite soil and river sand with the same grain size were compacted with low compaction energy, the weathered granite soil with crushability had higher dry density than river sand. However, when the compaction energy reached to certain point over limitation, the river sand had higher dry density than the weathered granite soil. The coefficient of permeability was lowest in the wet side rather than in the optimum moisture content, when the soil was compacted by adjusting soil water content. The reduction of permeability of soil due to the compaction was more apparent in the weathered granite soil than in the river sand. The highly significant correlation coefficient was obtained between the amount of particle breakage and dry density of the compacted soil.

• Magazine of the Korean Society of Agricultural Engineers
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• v.28 no.4
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• pp.66-76
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• 1986

This study was attempted to investigate the effects of delayed compaction on the unconfined compressive strengh and dry density of Soil-cement mixtures. Soil-cement construction is a time-consuming procedure. Time-delay is known as a detrimental factor to lower the quality of soil-cement layer. A laboratory test was performed using coarse and fine weathered granite soils. The soils were mixed with 7% cement at optimum moisture content and excess moisture content in part. Socondary additives such as lime, gypsum-plaster, flyash and sugar were tried to counteract the detri-mental effect of delayed compaction. The specimens were compacted by Harvard Miniature Compaction Apparatus at 0,1,2,4,6 hors after mixing. Two kinds of compactive efforts(9 kgf and 18 kgf tamper) were applied. The results were summarized as follows: 1.With the increase of time delay, the decrease rate of dry density of the specimen compacted by 9 kgf tamper was steeper than that of the specimen compacted by 18kgf tamper. In the same manner, soil-B had steeper decreasing rate of dry density than soil-A. 2.Based on the results of delayed compaction tests, the dry density and unconfined compressive sterngth were rapidly decreased in the early 2 hours delay, while those were slowly decreased during the time delay of 2 to 6 hours. 3.The dry density and unconfined compressive strength were increased by addition of 3% excess water to the optimum moisture content during the time delay of 2 to 6 hours. 4.Without time delay in compaction, the dry densities of soil-A were increased by adding secondary additives such as lime, gypsum-plaster, flyash and sugar, on the other hand, those of soil-B were decreased except for the case of sugar. 5.The use of secondary additives like lime, gypsum-plaster, flyash and sugar could reduce the decrease of unconfined compressive strength due to delayed compaction. Among them, lime was the most effective. 6.From the above mentioned results, several recommendations could be suggested in order to compensate for losses of unconfined compressive strenght and densit v due to delayed compaction. They are a) to use coarse-grained granite soil rather than fined-grained one, b) to add about 3% excess compaction moisture content, c) to increase compactive effort to a certain degree, and d) to use secondary additives like line gypsum-plaster, flyash, and sugar in proper quantity depending on the soil types.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.3
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• pp.47-54
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• 2012

As a large construction such as highway, dam, reclaimed land etc. increase in number more and more, large amount of fill materials are required. It is needed to utilize a gypsum which is a by-product yielded from chemical plants, as fill materials. Though some studies have been conducted to know a engineering characteristic of gypsum, it is not certain that water contents were checked at $45^{\circ}C$ dry oven. This study proposed that water contents must be measured at $45^{\circ}C$ dry condition because gypsum is changed to other types as a dry temperature. As the results obtained by compaction tests, it is found that moisture of gypsum in compaction must be within -5.0~2.5 % O.M.C (optimal moisture content).

• 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.

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.2
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• pp.1927-1936
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• 1970

This is a study on the influence of percent retaining of No. 10 sieve on soil compaction. Reviewing the test values in part 1 and part 2, a relative equation to predict maximum dry density and optimum moisture content was induced. Results of the study are as follow; 1. Maximum dry density increases according as percent retatining of No. 10 sieve increase untill 40%, but it decreases in more than 50%. 2. Maximum dry density has the greatest value at 25%, also it decreases according to increase or decrease at 25% in percent passing of No. 200 sieve. 3. Grain size distribution that Maximum dry density is largest, is 40% in 4.76mm to 2.0mm, 35% in 2.0mm to 0.074mm, 25% in lese than 0.074mm. 4. Correlation betwesn Maximum dry density and optimum moisture content made a curved line. The deviation between maximum dry density to be predicted from optimum moisture content and test values, is less than about 5%. 5. Range of deviation between optimum moisture content to be predicted from classification area and uniformity coefficient isless than about 20%, which belongs to range of moisture content that is correspondent with 95% of maximum dry density, generally.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.6
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• pp.1117-1123
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• 2016

Roller-Compacted Concrete Pavement (RCCP) is a type of pavement that shares conventional concrete pavement material characteristics and asphalt pavement construction characteristics. Even though RCCP is compacted in the same way and have similar aggregate gradation to asphalt pavements, its materials and structural performance properties are similar to those of conventional concrete pavement. With cement hydration and aggregate interlock, Roller-Compacted Concrete or RCC can provide strength properties equal to those of conventional concrete with low cement content. Therefore, compaction ratio of RCC can highly influence on its strength. In general, 95% of compaction ratio is required for proper strength development. RCC strength can be highly influenced by compaction energy which depends on compaction equipment and compaction method. Therefore, it is necessary to analyze the relationship between compressive strength and compaction ratio of RCC. RCCP specimens were produced at different compaction ratio by using different compaction methods and energies. The compaction ratio was defined by the ratio of the specimen's dry density and its maximum dry density. The maximum dry density was obtained from Modified Proctor test. 28 days compressive strength corresponding to each compaction ratio case was tested. Finally, the relationship between compressive strength and compaction ratio can be analyzed. For application of roller-compacted concrete in domestic construction site, the relationship is important for field compaction management.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.4
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• pp.59-66
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• 2006

In this study, construction modulus, void ratio and settlement characteristics of 38 CFRD in domestic and foreign countries were investigated from monitoring data. The effect of field dry density and void ratio to dam body was analyzed. The standard void ratio of CFRD that can be easily used by dam designers and field engineers was proposed from the monitoring data. It was confirmed that we can get the degree of compaction needed for reasonable compaction of dam body by calculating the field dry density from inverse operation of the standard void ratio. It was thought that the void ratio of CFRD depends on shape coefficient and in case of a high shape coefficient, the void ratio was high with its void ratio 0.17 -0.38.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.2
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• pp.84-89
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• 1991

This experiment was carried out to determine the effects of oversowing and other seeding methods (oversowing+ raking, oversowing+ raking+compaction, tillage+ broadcasting+ compaction and tillage + drilling+ compaction) on growth, dry matter and crude protein yield of alfalfa (Medicago satiua L.). The results obtained are summarized as follows:1. Soil pH and soil properties were improved by tillage.2. Establishment of alfalfa was increased with raking and compaction, and more by tillage than by oversowing(P