I tried to see how much sugar drestroy the conctete , I had 3 kg dissolved in 10 liter water . I put 5 liter "sugarwater" between the sponges when I clean the boom and the rest 5 liter "sugarwater" in the hopper and 10 more liter of pure water .

This is what happends ! I didn´t think it would destroyed the mud soo much !

I took 2 cube to test the mud...one before sugar and one after , from the same mix .
The mix was a C35/45 it shuold hold 45 Mpa + 10% = 49.5 Mpa and it hold 61.5 Mpa so it was no wrong with that mix , and the one with sugar hold 1.5 Mpa ! I could take it In my hand and crush it after 28 days !

Some one told me that as the sugar crystals formed they interfered with the structure of the structure of the concrete???

I know that sugar ruins concrete; but it still gets dry and hard.

I like a retarding agent, not sugar, for a move or required long wait.

I've used sugar as a cleaning out tool for the last 10 years or so. I put a large cup of sugar in the hopper AFTER I'm done pumping out,then I rinse the sugar into the hopper. I then suck a sponge and finish folding and loading up! When I get to the washout my hopper is still soupy , the edges aren't trying to set, and cleanout is twice as easy!!! Try it!

   Vasa,please explain what an Mpa is.

http://www.onlineconversion.com/pressure.htm

When you do the conversion, it is

Megapascal - to - PSI

MPa - to Pounds per sq inch

I prefer to use a 2 liter bottle of cheap cola and recirculate my hopper before pumping out and folding up to wash-out. You just have to make sure the mixer driver knows you put that cola in the truck, They all claim that they don't resell mud, but i know i've had a hot load or two!

they all re-sell left overs. i know this because i've done it myself a few times over these last few months.

   How much difference does it make when you add that 2 liter bottle of cola?

I always carry a bag of sugar in case of an emergency or if I have a long drive to wash out.....its amazing, dump the bag of sugar in the hopper, suck your sponge back...so it mixes up all the remaining mud, and bingo, instant soup....

i threw in a whole six pack of diet coke and it didn't work. J/K actually i used to use about 2 cans of coke in the hopper and it would work pretty well. i remember back in the early 80's when a big strike was going people would stand on a corner and wait for he redi mix to drive by and try and toss bags of sugar in the truck.