The Natural Philosopher wrote:

You obviously can't.

On the contrary, I have studied cement and concrete technology over
quite a few years. My work has involved concrete mix designs,
strength and durability testing.

Anyone else can, just by the feel.

Bull.

It goes crunchy when partly hydrated.

By that stage, it is very far gone. Cement will lose up to half its
strength without you ever being able to feel it.

So use a little more..the rest has just turned
into an expensive sand..;-)

All cement does is top the sand grains moving around.

Complete nonsense. The cement/water paste acts as an adhesive,
coating the fine and coarse aggregate to hold the whole mix together,
and giving the whole mix its fundamental strength.

All the sand does
is stop the aggregate moving around.

You really do talk so much rubbish.

Without the hydrated cement, it could do no such thing.

So, plonk! And goodbye.