ASTM1760: Bulk Electrical Conductivity of Concrete (Resistivity)​

ASTM C1760 is quick and non-destructive. Resistivity is an indication of pour connectivity, so the measurement can be used on its own, and as a predictor for diffusion coefficient and decay value.

How we test electrical conductivity of concrete

ASTM C1760 testing
Photo credit: Mary Vancura, 1760 resistivity measurement apparatus

The ASTM C1760 test measures the conductivity, normalized to the cross-sectional area, of electricity though a concrete sample. The inverse of conductivity is resistivity. In simple language, resistivity is a test of how difficult it is for a current to get from one end of the sample to another. This test actually measures the electrical resistivity of the concrete pore solution, and is therefore, a great stand- in for estimating the diffusion coefficient as both resistivity and diffusion coefficient are determined by the pore structure of the concrete.

Samples are stored in lime-saturated water so the pores are uniformly saturated with a known liquid. Measurements can be made as soon as the 4‑inch by 8‑inch sample is demolded and can continue over time. This test can be run on non-standard size samples, so it can be used to measure resistivity of core samples as well as cylinders.

Resistivity measurements can be used to estimate the decay coefficient in life cycle models. It can also be used to estimate diffusion coefficient based on correlation data between ASTM C 1556 or NT Build 492.

What works about the ASTM C1760 test:

This test is rapid and repeatable and can be used for quality control and design.

What doesn’t work about this test:

Nothing!