ASTM1760: Bulk Electrical Conductivity of Concrete (Resistivity)​

ASTM C1760 is quick and non-destructive. Resistivity is an indication of pore connectivity. That makes it useful either on its own or as a predictor of 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. That makes it useful for estimating the diffusion coefficient, as both resistivity and diffusion coefficient result from the pore structure of the concrete.

Samples soak in lime-saturated water to uniformly saturate the pores with a known liquid. Measurements on the 4‑inch by 8‑inch sample can begin immediately after demolding and can continue over time. This test also works on non-standard size samples. That is, it can measure resistivity on 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: