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Lab Resistivity testing on coarse aggregate

Lab Resistivity testing on coarse aggregate

Lab Resistivity testing on coarse aggregate

(OP)
I need to find a way (in the lab) to test the resistivity for aggregate having a nominal size of 3/4" with very little fines.  The material will not conform to AASHTO T 288.  Does anybody know of a way to do this?

RE: Lab Resistivity testing on coarse aggregate

Resistivity to electric current or to sulfides and salt attack?

RE: Lab Resistivity testing on coarse aggregate

(OP)
electrical

RE: Lab Resistivity testing on coarse aggregate

Need to go to the stockpile or pit where this material is from to get probes at a respectable distance apart. (lab dimensions will be too rough, =/- 50%).

RE: Lab Resistivity testing on coarse aggregate

That spec is for minimum resistivity in the lab.  It's used as a lower bound for resistivity.  The idea being a soil with lower resistivity has a higher corrosion potential.  If you're working with aggregate, the resistivity is likely to be very high.  Because of this, aggregate itself usually wouldn't be that corrosive.  The only case that I think it could be is if the aggregate is saturated in the field and the pore water has a high concentration of soluable salts.

RE: Lab Resistivity testing on coarse aggregate

Resistivity is a necessary parameter in the design of grounding for electrical substations. Low resistivity gives a safe ground system with larger grid of buried copper conductors and maybe no need for drilling a well for grounding purposes.

RE: Lab Resistivity testing on coarse aggregate

I wouldn't count on open graded, unsaturated aggregate having good enough properties to place a ground mat within it.  In fact, this material is typically used to eliminate step potential when it is a concern.

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