Integration of Spot Tests and Vibratory Roller Data in Rural Road Pavement Layers Made with Recycled Aggregates

Utilizing recycled aggregates of Construction and Demolition (C&D) and other wastes from different civil engineering activities in several layers of pavements, especially in low traffic roads, revealed a huge potential of improving sustainability in the infrastructures of rural transportation. Using modern smart technologies like Continuous Compaction Control (CCC) rollers for these materials needs performing studies to optimize the adopted engineering parameters and updating QC/QA assessment protocols. Spot tests such as in-situ densitometry, Plate Load Test (PLT), Light Weight Deflectometry (LWD) together with dynamic California Bearing Ratio (CBR), could contribute to the validation of the procedure of roller compaction. The correlation of these sets of data with the CCC results could present valid information on the stiffness development of different recycled materials from different sources and compositions, and their behavior under vibratory compaction. In this study, a number of spot tests were performed before and after constructing two superimposed layers of unbound and cement-bound recycled materials, compacted by CCC vibratory rollers, in order the evaluate the correlation of their results and the vibratory moduli. Despite the differences in the degree of correlation of spot tests and CCC data in sections of different recycled materials, similar trends were observed within the distribution of data from the field. The state of being unbound or cement-bound in trial pavements with recycled materials has effect on respond to vibratory roller and spot tests. Moreover, the correlation of various spot test results on different recycled materials expose the dissimilar responses related to their components, test contact area and test depth of effect on field pavement.