Question

B) Why do we state that the Teflon sheets do not completely remove friction in our cement cube testing? (3 points)

Answer 1

Thick sheets of Teflon accompanied by some axle grease are used on cement cube testing but instead of all this effort teflon sheet do not able to remove friction completely because teflon has a comparatively higher coefficient of friction than some other available material like Tungston disulfide which have less coefficient of friction and can work more effectively in place of the teflon sheet.

So now we can say that friction reduction was accomplished in two ways: applying two coats of dry lubricant graphite paint to the ends of the concrete cylinders, and using bearing plates that had been coated with Tungsten Disulfide [WS2].

Tungsten Disulfide was used because it bonds to metal surfaces, it has a very low coefficient of friction, lower than Teflon, and it is used in heavy duty moving parts; consequently, it should hold up to the high stresses created by concrete
compression testing.

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