Sulfur capping compound 1

[vollEngineer]

ASTM requires a new test be run for labs testing high-strength concrete in accordance with C617 that shows that 15 cylinders capped with sulfur exhibit strength within 2% of strength of 15 ground cylinders. In lieu of running these tests, the lab may choose to use the manufacturer's test data. However, I have not found a mfg yet that has run this test. Nor have any labs in my area. And my initial test came up 5% short of the ground cylinders.
Now, I am aware that capping with sulfur 7 days prior to testing should increase the strength. But other than that, does anyone have any guidance or knowledge of this testing being run?

 

[DarthSoilsGuy]

vol,
could you expand. I'm 1-yr out of the testing business. we would test the sulfer cmpd after casting it in steel mortar cubes. i think if it exceeded 8ksi in the 2" cube shape it was good. Is that no longer the case. 2% seems too tight. Were you getting 2% variance b/n just the cylinders that were ground?
-ham

 

[vollEngineer]

The 2-inch cube testing is not valid for high strength concrete testing. It is a 2% difference from the average and then within a certain standard deviation. Yuch! Of course the data points from the ground cylinders are not within 2% of each other. It is an excellent point and I will run some statistics to see what the range really is. BUT I am still wondering if anyone has done this in their lab...

 

[DarthSoilsGuy]

Vol,
I'm glad i got out. it sounds like there will be a lot of cooking going down in the CCRL QC books this year.
good luck,