Pavement Performance Of Lime-stabilized Soil With Small Lime Content And Its Application

The survey found that the subgrade of many rural roads in service is potentially in wet or over-wet state since its moisture is sometimes much greater than that in construction period. This makes the subgrade soften and then the pavement structure layers are possibly destroyed. In this paper, the elastic layer system theory was introduced to analyse the deformation and stress in the pavement structure layers and a set of laboratory experiments were done to investigate the variation of pavement performance of lime-stabilized soils with small lime content and its reasonable lime content. The feasibility of the lime-stabilized soils with small lime content improved the shallow subgrade was discussed. The following topics were studied:1. The elastic layer system theory was introduced to compute the deformation and stress in the pavement structure layers. The computed results showed that the pavement deflection and the tensile stress in its sub-base will increase with the increase of moisture of subgrade soil, but these indexes will decrease and the subgrade will be improved if the lime-soil cushion is set up.2. In order to study the strength and deformation behaviors of lime-stabilized soils with small lime content, the relationships between unconfined compression strength, splitting strength, compressive resilience modulus of lime-stabilized soils with different lime content, different degree of compaction and time were studied by lab tests. These tests results showed that all of the unconfined compression strength, the splitting strength and the compression modulus of resilience increase with the degree of compaction and the curing time. In addition, for a given degree of compaction, these strengths of the soils with the less lime content are potentially greater at the early curing time.3. The water stability of lime-stabilized soils with4%～8%lime content were studied by soak periods test and drying-moistening cycle test. The results showed that the unconfined compression strength, the splitting strength and the compression modulus of resilience of lime-stabilized soils decreased sharply in the initial of period. These indexes continue to decrease with the increase of soak periods and drove to stability of status at last time. These final values are equal to the results of the standard test. The results of drying-moistening cycle test show that the variation of the unconfined compression strength, the splitting strength and the compression modulus of resilience of lime-stabilized soils are similar to the results of the soak periods test.For rural road construction, the measure to improve the pavement structure was not used generally due to the lack of construction funds. This research results showed that, for the rural road in Luohe, the lime-stabilized soil with6%lime content and90%degree of compaction can meet the mechanical requirements of bed cushion, its rational thickness should be taken60～80cm, so it is a feasible measure to use low-cost lime-stabilized soils with small lime content improved the shallow subgrade.