Compaction Energy Level Research Articles

Strength and Deformation Properties of Compacted Cement-Mixed Gravel Evaluated by Triaxial Compression Tests

To achieve as possible as a high cost-effective construction of important civil engineering structures, such as bridge abutments, using cement-mixed gravel (CMG) for the backfill, a series of drained triaxial compression (TC) tests were performed on CMG specimens. Two types of well-graded gravels were used. Axial and lateral strains were measured locally on the lateral surface of solid cylindrical specimens. It was found that, for a same cement to gravel ratio by weight, the peak strength qmax tends to become the maximum when compacted at the optimum water content, w opt, for a given compaction energy level. This trend is due largely to the smallest compacted void ratio and partly due to the largest cement content per unit volume associated with the maximum dry density. The other influencing factors include an incidental optimum combination of strength and amount of cement paste that may be attained when compacted at w = wopt· The relationship between the ratio of "qmax at a certain molding water content, w" to "qmax at wopt, qmax.OMC" and the normalized deviation ratio of w from “wopt, | w- wopt | / wopt” is rather unique whether compacted at dry or wet of optimum, for different compaction energies and for the two types of gravel. It is also shown that the initial Young's modulus tends to become the maximum when compacted at wopt while the pre-peak stiffness and post-peak ductility generally increase with an increase in the molding water content. Based on the test results, it is recommended to compact a given type of cement-mixed gravel around at wopt ensuring that the compaction is not made dry of optimum for a given compaction energy.

Effects of Moulding Water Content on the Stress-Strain Behaviour of a Compacted Silty Sand

Compacted soil is often employed in geotechnical constructions. A set of triaxial compression tests was executed on fully saturated specimens of a medium-fine compacted soil to investigate the influence of preparation water content on the stress-strain behaviour. Specimens were prepared by compacting at different water contents on the dry and wet sides of the optimum and around the optimum for different compaction energy levels. A state-of-the-art triaxial apparatus, which allows investigation into soil behaviour from very small strains up to failure, was used. It is shown that, as previous researches have indicated, compacting soil at different moulding water contents produced materials with different microstructures. The test results showed that the effect of soil microstructure was noticeable at small strains but it decreased with an increase in the strain and had little or no effect on the shear strength envelope in terms of effective stresses. Particularly, it is shown that, even after removing the effects of compacted dry density, the specimens compacted at the optimum water content presented not only the lowest isotropic compressibility, but also the highest initial stiffness and damping ratio at small strains. As the strain level increased, the stress-strain behaviour tended to be more uniquely controlled by the instantaneous dry density. It was also the case of the dilatancy characteristics, which controlled the pattern of effective stress path.

Swelling behaviour of compacted fine-grained soils

The swelling behaviour of three compacted Cyprus soils varying significantly in their physical properties have been studied with variation in compaction energies from standard Proctor compaction to modified Proctor. For comparison, studies have also been made with kaolinite and a highly plastic montmorillonitic clay. Both percent swell and swelling pressure are significantly influenced by the compaction energy. There is an unique relationship between percent swell and the swelling pressure irrespective of the soil type and the level of compaction energy. The percent swell–time relationship could be identified as a rectangular hyperbola facilitating the prediction of ultimate percent swell with a few initial results. The swell–log time relationship has three distinct phases of initial, primary, and secondary swelling. The secondary swell could be distinctly identified, and a knowledge of the rate of secondary swelling enables the prediction of long-term swelling. The study focuses on the attention of the significant influence of the compaction energy on percent swell/swelling pressure.

Use of Dynamic Cone Penetrometer to Control Compaction of Granular Fill

Granular material is commonly used as backfill and embedment material for buried structures, including thermoplastic pipe. Proper compaction of this material is crucial to the successful performance of the pipe. However, the commonly used Proctor density approach cannot be used for the field compaction control of these materials because it does not provide a well-defined moisture-density relationship. An alternative method used by the authors for compaction control of such materials is described. This method involves a device known as the dynamic cone penetrometer (DCP). Findings are presented from a series of DCP tests conducted on a range of granular backfill materials that belong to ASTM D 2321 Classes I and II. These materials were compacted using ( a) an impact rammer and ( b) a vibratory plate compactor. The level of compaction energy was varied by changing the number of passes. The data obtained from these tests are presented in the form of DCP blow count profiles, which are then used as the basis for comparison between different materials, compaction equipment, and levels of compaction energy. A series of full-scale load tests conducted on high-density polyethylene (HDPE) pipe installations is also described. An overview is provided of how the DCP data may be combined with load-deflection data from full-scale load tests to establish guidelines for compaction control of pipe backfill.

Some properties of A sedimentary laterite soil as engineering construction material

A sedimentary laterite soil is examined for its suitability as a construction material by the consideration of its mineralogy and basic geotechnical properties as well as its consolidation and permeability in the compacted state. Three compaction energy levels are utilised.

Cone Index Prediction of Compacted Soils

ABSTRACT THE cone index prediction equation for three soil textures varying in organic matter contents that were subjected to three levels of compaction energy was obtained. The equation is of the form: (CI/Pc) = A (Ts/Qp)^. The functional form of A and n was determined for sandy loam, clay loam and clay for varying moisture contents. The cone indices of the soils estimated with the developed model were in close agreement with measured values. The validation of the model with field measured cone index values showed a high degree of accuracy between measured and predicted values.

Shear Strength Prediction of Compacted Soils with Varying Added Organic Matter Contents

ABSTRACT THE shear strength of compacted soils is affected by many factors including soil density, overburden pressure, moisture content, energy applied for compaction and soil type. Measurements were made of the shear strength of three soil textures, varying in organic matter contents and subjected to three levels of compaction energy. Soil compaction increased the shear strength of the soils irrespective of moisture content, while organic matter incorporation decreased their shear strength. Based on the liquid limit, the pressure applied for compaction and the water content, a method for predicting the shear strength of soils was developed. The estimated shear strength using the model was in good agreement with the measured values.

The Effects of Soil Compaction and Organic Matter on the Growth of Bush Beans

ABSTRACT BUSH BEANS (Phaseolus vulgaris) were planted in three soil textures having varying organic matter contents that were subjected to three levels of compaction energy. Measurements were made of some plant and yield parameters in a controlled environment. Soil compaction decreased the fresh yields of the crop, the plant height, the root dry matter and increased the plant diameter. On the other hand, organic matter incorporation which tends to reduce compaction increased the fresh and dry yields of the crop, the plant height, the leaf area index and the root dry matter. The results indicate that there is a great potential for using organic matter to alleviate the problems of soil compaction in crop production.