Instrument Manual for Prototype Concrete Consolidation Monitoring Device.

摘要

This manual describes a Consolidation Monitoring Device (CMD) which has been designed to monitor consolidation of fresh concrete by measuring its density. Nuclear technology is used for sensing density by employing the Compton scattering phenomenon generally called nuclear backscatter. The source of nuclear energy for the instrument is Cesium 137 (137Cs) which emits gamma rays capable of penetrating several inches into the concrete. These rays,scattered about within the concrete,return in part to the sensing instrument which measures the rate of return and displays the count rate in terms of density or pounds per cubic feet (pcf). The CMD instrument is capable of measuring density on a continuous basis and has been adapted for measuring the density of a freshly laid concrete roadway while attached to the rear side of a slipform paver. The operation,calibration and maintenance procedures used in routine density measurements are described in detail in this manual. In addition,it provides information concerning the principles of density measurement,technical specifications of the various components, a functional description of the circuitry,and instructions on radiation safety. Illustrations and circuit schematics are contained in the body of the manual and a parts list is in the Appendix.