Study on the Compaction Effect Factors of Lime-treated Loess Highway Embankments

Abstract

This paper presents a study to investigate the effects of water content, lime content and compaction energy on the compaction characteristics of lime-treated loess highway embankments. Laboratory compaction tests were conducted to determine the maximum dry density and optimum water content of loess with different lime Contents (0, 3, 5 and 8%), and to examine the effects of water content, lime content and compaction energy on the value of and . In situ compaction tests were performed to obtain the in situ dry density . The value of − achieves it's maximum value when in situ water content − was larger than the value of (+1-2%). The degree of compaction can hardly be achieved to 100% in the field construction of embankments. Higher water content and compaction energy is needed for optimum compaction.

Evaluation on Strength Properties of Lime–Slag Stabilized Loess as Pavement Base Material

“…These results also imply that after lime and slag were added to the loess, more water was needed to achieve the optimum density as water was required to react in the hydration process. The decrease in maximum dry density is related to the flocculation of soil particles and the production of cementitious compounds [6]. When lime was added to loess with water, cation exchange of calcium quickly occurs in the lime-soil mixture, which causes flocculation of inter-particles and the decrease of loess plasticity, and thus results in extra effort required to compact the mixture [10].…”

“…In the case of lime-soil mixture in general, the dissolved of lime provides a highly alkaline environment, in which the silicate and a small amount of aluminate ions was produced by the dissolution of soil particles. Therefore, the main cementitious material was calcium silicate hydrate, which is formed by the reaction of silicate and calcium ions in an alkaline state [54], and this process was referred to as pozzolanic reaction, in which the active components, such as silica and alumina, of loess react with calcium hydroxide of lime to form chemical products, such as calcium silicate hydrate, calcium aluminate hydrate, or calcium sulphate aluminate hydrate [6,7,26]. The introduction of slag in the lime-soil mixture changes the reactants of the pozzolanic reaction, as well as provided additional alumina, calcia, silica, and magnesia to the lime-soil mixture [55].…”

“…Loess is mainly distributed in the upper and middle part of China's Yellow River and the total distribution area is about 630,000 km 2 , which is around 6.3% of the total land area of China [1][2][3][4]. Although loess in its dry state shows high strength and small deformation, it exhibits large-scale deformation and deterioration of mechanical properties when contacting with water, and this phenomenon is known as collapsibility [4][5][6][7]. The collapsibility of loess may cause problems, such as landslides, soil erosion, ground cracking, and settlement.…”

“…Previous studies revealed that the intrinsic characteristics of the porous structure of loess and the composition of cemented material are the main causes of collapsibility [8][9][10][11]. Given this, stabilization of the loess is of great significance to mitigate the occurrence of geologic hazards [6,10,[12][13][14][15].…”

Experimental investigation on strength development of lime stabilized loess

“…Loess is a widespread problematic soil in China due to its unfavorable engineering characteristics, such as collapsibility, erosion, and friability. [1][2][3][4][5][6] Without proper improvement of loess, some severe issues may be encountered in engineering practices, such as landslides, ground ssures and land subsidence. [7][8][9][10][11][12][13] Therefore, stabilization of loess by cementitious materials has been commonly adopted in pavement base layers and road subgrades.…”