Experimental verification of roller-integrated compaction technologies

Roller-integrated compaction technology that monitors roller behavior in response to machine-ground interaction was shown to indicate the characteristics of compacted soil. To support the development of specifications for roller-integrated compaction systems and accelerate implementation of the technology into practice, this research identified the relationships between roller-integrated measurement values and the in-situ compaction measurements that are commonly used in the United States for earthwork quality assurance.; The experimental study evaluated the following roller-integrated compaction systems: (1) Ammann soil stiffness kS, (2) Geodynamik compaction meter value, and (3) Caterpillar machine drive power. Roller data for these studies were obtained by compacting a wide range of cohesive and granular soils using static padfoot and vibratory smooth drum rollers. The soil at different states of compaction was also tested for properties using other in-situ testing technologies. The experimental testing methods provided both roller-measured parameters and material characteristics that were used in performing statistical analyses.; Linear regression analyses using compaction data from test strips showed that soil properties measured using in-situ test devices can be predicted from roller-integrated measurement values, provided that measurement variability is mitigated with spatial averaging techniques. The in-situ soil properties are particularly well correlated when moisture content and interaction terms are incorporated into a compaction model initially derived from laboratory moisture-density-energy relationships. Multiple linear regression analysis results helped to identify and quantify the factors affecting roller response, in particular soil moisture content.; Roller-integrated compaction technology was also investigated for layered soil conditions, with the measurement values affected by the upper compaction layer and the underlying soil layers. The individual soil layers were represented as elastic springs connected in series, and equivalent stiffness for the layered-soil system was formulated using principles of elastic theory. Experimental compaction data supported the new model. The validated model was then used to make inferences regarding the influence of layer thickness and elastic modulus on roller-measured stiffness. The assertions were supported by both experimental and theoretical evidence.