Electrical Methods for Evaluating Mass Transport Properties of Concrete-Standardization of Bulk Resistivity Tests for Fluid Penetration Resistance (PDF)

Standardization of Bulk Resistivity Tests for Fluid Penetration Resistance (PDF)

Pdf Summary

The document discusses the standardization of bulk resistivity tests to assess the resistance of concrete to fluid penetration, which is critical for preventing deterioration by limiting water and aggressive ion ingress. The need for standard yet efficient, precise tests that can relate performance to concrete durability is highlighted, emphasizing the importance of having appropriate acceptance limits for different exposure conditions. While traditional chloride diffusion tests are cumbersome and impractical for quality control in construction, rapid index tests like bulk and surface resistivity are more viable.<br /><br />The document compares various commercial devices for measuring bulk resistivity, such as Germann Instruments' Merlin, Giatec RCON, and Proceq Resipod. These devices differ in waveforms, frequencies, and analysis methods, yet they provide similar results. Standardizing these devices involves adopting a performance-based approach using a verification cell to ensure accuracy without prescribing specific equipment.<br /><br />The standardization process at ASTM involved verifying resistivity measurements against precision resistors and capacitors. This revealed that the addition of capacitance did not significantly affect resistivity values. The proposed test method includes measuring bulk resistivity to calculate the formation factor, accounting for pore geometry and connectivity, removing the effect of pore solution conductivity. The influence of saturation, ambient conditions, and equipment pressure on test accuracy, the potential for quicker testing before strength assessments, and consistent results within expected error margins were highlighted. These tests promise a rapid, practical means to assess and ensure concrete durability in varying conditions.

Keywords

bulk resistivity

concrete durability

fluid penetration

standardization

quality control

resistivity devices

ASTM verification

formation factor

rapid testing

pore geometry