Abstract: Since the pioneering work of R. R. Proctor some 40 years ago, soil mechanics engineers and contractors have been accustomed to evaluating a compacted fill in terms of relative compaction. Because of the many similarities, the terms relative compaction and relative density can be confused. The study presented herein was made to show the distinction between terms and to illustrate a simple and practical correlation between them.

Abstract: To assess benefits to be gained from increasing compaction specifications for subgrades, a laboratory program was performed to determine the effect of closed-system freeze–thaw cycling on resilient and residual strains, resilient moduli, and volume changes of till specimens that had been compacted to various densities and water contents and subjected to repetitive loading in a constant triaxial stress system.The study showed that if compaction of this soil was increased to a higher density at a lower water content, strains, modulus, and freeze–thaw effects would be improved to such an extent that a significant reduction in pavement structure would be possible. It also showed that the extent to which a reduction could be made was dependent on the ability of the subgrade to maintain the compaction density and water content throughout its design life.

Abstract: In the Pukekohe area, which lies about 30 miles (50 km) south of Auckland, vegetables for market have been grown for at least 30 years in some gardens on Patumahoe clay loam, a naturally well structured soil derived from volcanic ash. In some areas this soil now shows signs of structural deterioration. Samples taken from the surface 8 in. of gardens of various ages show that the content of organic carbon of the soil has declined from 5.5 percent by weight to a little over 2 percent in 30 years of market gardening. Water-stable aggregates larger than 2 mm in diameter have almost disappeared over the same period. However, these have broken down to smaller aggregates, not to the ultimate soil particles, and soil compaction due to the breakdown of aggregates on wetting does not appear to be severe. In certain gardens, of various ages, the soil at a depth of 3 to 8 in. contained as little as 4 to 8 percent by volume of pores drained by a tension of 50 cm of water. The occurrence of these compacted zon...

Abstract: RESEARCH WAS CARRIED OUT TO STUDY THE CORRELATION BETWEEN ENGINEERING AND PHYSICAL PROPERTIES OF FIELD AND LABORATORY COMPACTED SPECIMENS. THE PARAMETERS EVALUATED ARE DIVIDED INTO THREE GROUPS: PHYSICAL CHARACTERISTIC PARAMETERS -- DRY DENSITY AND MOISTURE CONTENT; PRIMARY RESPONSE PARAMETERS DESCRIBING NON- FAILURE BEHAVIOR -- CREEP MODULUS, COMPLEX MODULUS, AND RESILIENT MODULUS; AND ULTIMATE RESPONSE PARAMETERS DESCRIBING BEHAVIOR AT FAILURE -- SHEAR STRENGTH AND PERMANENT DEFORMATION AT FAILURE. THE PHYSICAL SOIL PARAMETERS DESCRIBING THE INTERRELATION BETWEEN MOISTURE, DENSITY, COMPACTION ENERGY, AND METHOD OF COMPACTION CAN BE USED FOR THE CORRELATION OF LABORATORY AND FIELD SPECIMENS. /AUTHOR/

Abstract: The effect of fertilizer response to various levels of soil compaction on the growth, nutrient uptake and yield of wheat in an artificilly completed fine sandy loam soil was studied. Eight levels of compaction (1.11, 1.18, 1.26, 1.35, 1.44, 1.53, 1.61 & 1.70 gmlec) and two levels of fertility (control and 150 ppm N + 75 ppm P2O5 + 75 ppm K2P) were tried in three replications. Compacting the soil from 1.11 to 1.70 gmlec resulted in large decrease in its total and aeration porosity and hydraulic conductivity. The relationship between bulk density of soil and crop growth ornutrient uptake was found parabolic in nature. An optimum compaction of 1.35 gm/cc was recorded as most favourable for crop growth. Fertilization failed to alleviate the adverse effect of soil compaction. Fertilizer response was maximum at the optimum bulk density of 1.35 gm/cc and was considerably reduced at higher and lower compaction levels. Interaction between compaction and fertility was found significant on number of ear bearing tillers, uptake of nitrogen and phosphorus.

Abstract: EIGHTEEN SOIL MATERIALS VARYING FROM SUBGRADE SOILS TO FLEXIBLE BASE MATERIALS WERE INVESTIGATED FOR THE RELATIONSHIP BETWEEN THE COMMONLY USED TEXAS COMPACTION RATIO DENSITY AND THE DENSITY OBTAINED BY CERTAIN GYRATORY COMPACTION PROCEDURES. THE DEGRADATION OF THREE OTHER SOFT CRUSHED LIMESTONE SAMPLES CAUSED BY USE OF THE GYRATORY PROCEDURE WAS INVESTIGATED. THE DATA OBTAINED INDICATE THAT A METHOD HAS BEEN ESTABLISHED WHEREBY GYRATORY DENSITIES (WHEN MODIFIED WITH A COMPACTION K FACTOR) CAN BE RELATED TO THE COMPACTION RATIO DENSITIES THAT ARE COMMONLY SPECIFIED IN TEXAS. THE METHOD PROVIDES FOR TESTING THE SAME MATERIAL THAT IS OBTAINED IN DIGGING TEST HOLES, THEREBY ELIMINATING THE NECESSITY FOR PERFORMING PRELIMINARY MOISTURE-DENSITY CURVES AND ALSO THE "GUESSING GAME" FOR IDENTIFYING THE PROPER MOISTURE- DENSITY CURVE FOR USE. FOR MOST FLEXIBLE BASE MATERIALS, THE METHOD SHOULD BE FAIRLY RAPID IN THAT MOISTURE CONTENT DETERMINATIONS CAN BE ELIMINATED BECAUSE DRY WEIGHT IS A CONSTANT AND CANCELS OUT OF THE CALCULATIONS. RESULTS INDICATE THAT A RATHER LARGE AMOUNT OF DEGRADATION DOES OCCUR BUT ITS PRESENCE DOES NOT CAUSE THE SHAPE OR MAGNITUDE OF MOISTURE-DENSITY RELATIONSHIP CURVES TO CHANGE. /AUTHOR/