Soil stabilization is the alteration of soil properties to improve the engineering performance of soils in roadway construction. The properties most often altered are density, water content, plasticity and strength. Modification of soil properties is the temporary enhancement of subgrade stability for roadway construction. Fly ash stabilized base courses are proportioned mixtures of fly ash, aggregate, and either cement or lime that, when properly placed and compacted, produce a strong and durable pavement base course. Fly ash stabilized base course is suitable for both flexible and rigid pavements. Fly ash stabilized base course is cost effective substitute for full-depth asphalt treated, cement treated, and crushed stone base courses. Fly ash can be used as flowable fill material after blending with cement, water, and sometimes with fine aggregates. Flowable fill is self-levelling, self-compacting, and non-settling roadway construction material used for different purposes, hence fly ash is playing vital role in roadway construction. The course material is based entirely on FHWA-IF-03-019 Technical Report Chapter Numbers 4 and 5 of Fly Ash facts for Highway Engineers.

At the conclusion of this course, the learner will have a better understanding about the Role of Fly Ash as Stabilized Base Course Material and Flowable Fill in Roadway Construction as well as the following:

• Understanding applicability of flow able fill for various roadway construction and geotechnical applications
• Knowledge of various specifications and testing standards of fly ash stabilized base course mixtures
• Knowledge of various specifications and testing standards of flowable fill design mixtures