Current methods for assessing quality control in constructing embankment and unbound layers are based on the determination of parameters such as field unit weight. However, most of the design methods are based on engineering properties of the materials, including their stiffness or strength values. In fact, this is a missing link between the design processing and construction quality control methods. Hence, quality control procedures should be based on criteria that are closely correlated with the performance parameters used in the design such as elastic stiffness modulus. For this purpose the use of Portable Falling Weight Deflectometer (PFWD) in the determination of earthworks layers elastic moduli is rapidly increasing The purpose of this study was to evaluate the stiffness modulus as a construction quality control criterion in unbound materials and embankments. A laboratory testing unit box was prepared in which an unbound material was compacted at different compaction levels. Then the stiffness modulus of each compacted layer was determined under Portable Falling Weight Deflectometer (PFWD). The results indicated acceptable correlations between the stiffness modulus and both compaction percentage and moisture percentage. However, it was found that the stiffness modulus is a more appropriate indicator than compaction percent in discerning the true behavior of the unbound layers