Measuring Modulus for Better-Performing Pavements

The latest of TRB's National Cooperative Highway Research Program (NCHRP) Ready Results examines NCHRP Research Results Digest 391: Modulus-Based Construction Specification for Compaction of Earthwork and Unbound Aggregate. Proper compaction of roadway base and subbase is vital to ensure good pavement performance throughout its life span. Modulus, a measure of stiffness, predicts the performance of pavement. Modulus can be used specifically for recycled materials since there is little data relating the density of these materials to their strength. This fact sheet explores how agencies can use modulus to maximize the value of pavement construction investments.