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The objective of this paper is to propose a compaction control method that facilitates the use of expansive soil, as embankment material for highways in humid climates. Three types of expansive soils, utilised as general embankment fill in Southern China, were selected for investigating the physical, compaction, and shear strength properties. The compaction-control method was proposed based on the compaction curve revealed by the dry preparation method, associated with the corresponding soaked California bearing ratio. The site test and long-term monitoring were conducted in an embankment in Ningming, which was filled with compacted expansive soil controlled by the suggested method. The laboratory test results showed that the maximum dry unit weight obtained from the dry preparation method was less than that generated from the moist preparation method, while the optimum moisture content acquired from the dry preparation method was greater and closer to its natural moisture content. The moisture content corresponding to maximum CBR was 2% larger than the optimum moisture content. The in-situ monitoring results presented that the moisture content of the constructed embankment was close to its natural moisture content or plastic limit, the maximum settlement was 70.6 mm, and the maximum horizontal displacement was 20 mm. [ABSTRACT FROM AUTHOR]

Strength properties of compacted ash layers depend to a great extent on the moulding conditions. This paper focuses on the effects of compaction energy and degree of saturation on strength characteristics of compacted pond ash. The pond ash sample, collected from the ash pond of Rourkela Steel Plant (RSP), was subjected to compactive energies varying from 357 kJ/m3to 3488 kJ/m3. The optimum moisture content and maximum dry densities corresponding to different compactive energies were determined by conventional compaction tests. The shear strength parameters, unconfined compressive strengths (UCS) and California bearing ratio (CBR) values of specimens compacted to different dry densities and moisture content were assessed and reported. The effects of compaction energy and degree of saturation on shear strength parameters i.e. unit cohesion (cu) and angle of internal friction (Ф) values and also the UCS values are evaluated and presented herein. The results indicate that the dry density and strength of the compacted pond ash can be suitably modified by controlling the compactive energy and moulding moisture content. The strength achieved in the present study is comparable to the good quality, similar graded conventional earth materials. Hence, it may be safely concluded that pond ash can replace the natural earth materials in geotechnical constructions. [ABSTRACT FROM AUTHOR]

• The role of the compaction effort on geotechnical behavior of waste foundry sands was investigated. • Increasing of compaction effort causes remarkable changes in terms of bearing capacity and shear strength. • Suction plays a remarkable role in the behavior of waste foundry sand after being air-dried. • Waste foundry sand requires a rigorous compaction control. Brazil produces more than 3 million tons of waste foundry sands (WFS) each year. Although this material presents characteristics that fulfill the environmental requirements to be recycled and used as a building material, the lack of information regarding its geotechnical behavior inhibits its use, mainly in applications that require good performance. Therefore, this study investigates the role of the compaction effort on the behavior of compacted WFS considering its application as a building material in geotechnical work. The experimental procedures include X-ray fluorescence analysis, scanning electron microscopy, determination of compaction curves, California bearing ratio (CBR), the execution of unconfined compression, direct shear, and oedometric tests. Geomechanical tests were conducted on specimens compacted with three distinct compaction efforts: 600 kJ/m3, 1260 kJ/m3 and 2700 kJ/m3. The WFS is composed mainly of quartz particles with subangular to subrounded shape. Fines are 12% of its composition, and WFS is classified as a well-graded material. Optimum moisture content ranges between 9.0 and 11.5%. The higher the compaction effort, the lower is the void ratio. Despite the differences in the void ratios are small, they affect the CBR values dramatically. Compaction effort increases friction angle and unconfined compressive strength and reduces compressibility. Suction plays a remarkable role in the behavior of such material after being air-dried. This study can contribute to a better understanding of potentialities and limitations for the use of WFS in compacted conditions. [ABSTRACT FROM AUTHOR]