Moisture Content Monitoring using a Nuclear Moisture Gauge and Preliminary Findings at Alabama Highway 5

Abstract

Expansive soils cause damage to lightly loaded foundations and structures across the world. Alabama Highway 5 was built directly on an expansive clay soil. In past years it has experienced tremendous amounts of damage due to the shrinking and swelling of the clay subgrade. Several remediation strategies were utilized in an effort to increase the life of the pavement surface. These strategies include efforts to increase drainage both beneath the pavement and beneath the shoulder, lime columns, vertical moisture barriers, and paved shoulders. In addition, each remediation strategy was instrumented with a variety of sensors to monitor pavement distress and soil behavior. To provide a way to quickly measure in-situ water contents with depth, access holes were installed at AL-5 for a nuclear moisture gauge. Preliminary findings indicate that at the time of publication, the pavement sections are performing well with the exception of the vertical barriers. Continued monitoring will help determine the effectiveness of each remediation strategy.