The mixture and mixture properties of lime-fly ash-mixtures (LFA) are described as well as pavement behavior and performance, selection of mixture proportions, construction procedures, applications and limitations. The quality of a LFA-stabilized mixture is highly dependent on the aggregates used. Generally, the lime-plus-fly ash content of a mixture ranges from 12 percent to 30 percent with lime-to- fly ash ratios of 1:3 to 1:4 being common. The critical engineering properties, namely strength, modulus of elasticity, Poisson's ratio, fatigue, autogenous healing volume changes and durability are influenced by the constituent materials and by proportions, processing, compaction, and curing. Test data correlated with theoretical analyses confirm that the load distribution characteristics of pavements with layers of LFA mixes are essentially those of a slab. It was found that the stiffer LFA layers distribute the load over large areas of the subgrade by the slab action, thus transmitting low vertical stress to the subgrade. The primary factors affecting the performance of LFA pavements were studied using scale models in laboratory and normal traffic conditions. Two types of construction related distress observed on LFA pavements were: distress when naterial becomes saturated before setting; distress when traffic causes cracks in partially set LFA material.
Abstract