Low-dose cement stabilized large particle size graded crushed stone: Laboratory and field investigations

Abstract

Compared with traditional graded crushed stone (GCS), the maximum aggregate size of large particle size GCS (LPS-GCS) is larger and the content of large-size aggregates is more, which can form an interlocking skeletal structure with a stronger bearing capacity. Nevertheless, LPS-GCS occasionally exhibits unstable performance, and one effective way to enhance LPS-GCS's mechanical and physical properties is to stabilize it with low-dose cement. In this study, four cement contents (1.5 %, 2.0 %, 2.5 %, and 3.0 %, by mass) were selected to form low-dose cement stabilized LPS-GCS (LCS-LPS-GCS) mixtures with a maximum aggregate particle size of 53 mm. Unconfined compressive strength (UCS) and compressive resilient modulus (CRM) tests were performed on LCS-LPS-GCS samples for different cement contents and curing times. Moreover, prediction models and correlations for the UCS and CRM at different curing times were established. Furthermore, a test road was used to evaluate the LCS-LPS-GCS's field compaction level and deflection. Laboratory test results indicated that while the California bearing ratio was significantly higher than that of conventional GCS, the maximum dry density of LPS-GCS designed in this study was close to that of conventional GCS. With the same cement content, LCS-LPS-GCS outperformed conventional GCS in terms of UCS and CRM. Based on the variation law of the mechanical properties, the ideal cement content should be around 2.5 %. There was a strong positive correlation between UCS and CRM scores from LCS-LPS-GCS. The UCS and CRM were appropriate to be predicted by exponential and growth functions models, respectively. The field investigations indicated that asphalt pavements reconstructed with LCS-LPS-GCS had high compaction and low deflection, resulting in better bearing capacity and durability. The results of this investigation can serve as a reference for the design and application of LCS-LPS-GCS base for long-lasting and resilient pavements.