BACKGROUND: The use of cementiously stabilized materials, such as lean concrete, cement stabilized aggregate, and soil stabilized with cement, lime, fly ash, or combination thereof in subgrade, subbase, and base layers of flexible and rigid pavement structures is a widely accepted practice by many state highway agencies. Although a great deal of research has been performed on the properties of these materials, limited research has related the properties of such materials (e.g., shrinkage) to performance of the pavements in which they are used. The AASHTO Interim Mechanistic-Empirical Pavement Design Guide Manual of Practice (MEPDG) (see Special Note A) developed under NCHRP Project 01-37A provides a methodology for the analysis and performance prediction of pavements incorporating such layers. However, the short- and long-term properties of these materials differ substantially depending on the type and quantity of stabilizing agent, pavement structure, environmental conditions during and after construction, loading, etc. The characterization of such materials, the changes of their properties over time, and their distress models have not been adequately addressed in the MEPDG. Also, limited material properties have been considered; other properties may have significant influence on the long-term performance and need to be considered.
OBJECTIVE: The objective of this research was to recommend performance-related procedures for characterizing cementitiously stabilized pavement layers for use in pavement design and analysis and incorporation in the MEPDG. This research dealt with material properties and related test methods that can be used to predict pavement performance, and considered subgrade, subbase, and/or base materials stabilized with hydraulic cement, fly ash, lime, or combinations thereof.
STATUS: The project is complete; the final report has been published as NCHRP Report 789, available at https://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_789.pdf
The appendices are available at https://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_789_Appendices.pdf