Implementation of an Automated Test Setup for Measuring Electrical Conductance of Concrete

About the report:

This project was designed to provide the Virginia Department of Transportation (VDOT) with an automated laboratory setup for performing the rapid chloride permeability test (RCPT) to measure the electrical conductance of concrete in accordance with applicable standards. As an increasing number of construction projects is becoming subject to concrete permeability acceptance testing, there is a growing need for conducting laboratory RCPT in a timely and expedient manner. Typically, concrete cylinders arrive at VDOT's materials laboratory in large batches, sometimes more than 100 units at a time. This often results in backlogs in processing and leads to considerable delays. The lack of commercially available test equipment created a need to develop an automated device that could expedite large scale production testing. The Virginia Transportation Research Council was contacted to provide technical assistance. This report describes the practical implementation of a workable RCPT device. An automated laboratory setup for conducting RCPTs was developed and implemented at VDOT. The microprocessor-controlled device is capable of unattended measurement and monitoring of up to 32 concrete specimens at a time in accordance with AASHTO and ASTM test methods. The device is based on the Campbell Scientific CR10X Datalogger interfaced with the Campbell Scientific AM16/32 Multiplexer. Date- and time-stamped test records are stored electronically in ASCII format. As there are no commercially available devices with a comparable function, it is difficult to assess the initial cost of development and setup. There are, however, substantial cost savings associated with the operation of this device. It is estimated that the resultant savings are equivalent to the costs of one full-time technician position in VDOT's materials laboratory. These costs are approximately $46,000 per year, accounting for salary and benefits.

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