What does suger really do?

[westside198]

Does sugar really ruin concrete or just sustain the length of hydration. How many 5# bags of sugar would it really take to ruin a 10 yard load any ideas.

[speedy]

I don't think that sugar can completely stop the hydration reaction, just slow it down quite a bit. The sugar combined with the water to make it unavailable in the short term. Eventually, the hydration reaction will win win out, as the cement wants the water more than the sugar does. I would imagine there is some detrimental effect on the ultimate strength of the concrete.

I had been told the a big bottle of Coke or Pepsi will do more harm to a load of concrete and a pound of sugar. Must be something to do with the carbonation, or other chemical contained in it. (and we drink the stuff??)

I once heard a rumour of a disgruntled (former) employee dumping bottles of Pepsi into the mixer drums of 5 trucks at a concrete grain elevator under construction. this was at the very beginning as it was a 24 hr/day - 8 day log continuous slip-form pour. 3 trucks had already loaded, and the 4th guy spun his drum backwards before loading, (as had been his habit for years, to make sure there wasn't a bird or crittter or some such in the drum) and a brown liquid came out. He called the foreman, who checked the 5th truck as well....same thing. They dumped the first 3 loads. Would have made life interesting (maybe) when they started jacking the slip-form....Who knows???

I've seen concrete workers use Coke to retard the reaction on the surface of a sidewalk when doing exposed aggregate. I've also watched a guy spray a water/molasses mix on the forms for a set of steps that was to have exposed aggregate on the vertical surfaces. he used the same mix on the horizontal area. they pulled the forms off the next day (pour was done in the late afternoon. They used a gas engine powered pressure washer at an idle to expose the aggregate - worked like a charm, he hardly busted a sweat!

[westside198]

thanx speedy, hey isnt that a bad name for a mixer driver. This aint no f**king speeding contest!

[intruder473]

sugar or soda doesn't stop hydration it effects the preformance of the concrete. If you have some sort of breakdown and you have to dump sugar in the load it will make it so that who ever has to jack hammer the inside won't have to work so hard.

[speedy]

westside198 said:

thanx speedy, hey isnt that a bad name for a mixer driver. This aint no f**king speeding contest!

Well, for starters, I'm not a mixer driver, I'm a concrete pumper. I own & operate Speedy Crete Concrete Pumping. i'm from swift Current, Saskatchewan (Where the HELL is that??) It's in Canada, right above Montana. The nickname for the town is 'Speedy Creek', thus the name of my company is a play on words. Besides, Concrete pumping is a SPEEDY way to place concrete.

[westside198]

Pumpers in l.a. charge $150 setup and $8 a yard! how much is it were yall are

[concretejoe]

A lot of retarders are sugar based.

[batchmaster]

Sugar interferes with the cement binding process in the concrete. One theory suggests that when the concrete mixture contains sugar, the sugar molecules attach themselves to the hydrating cement and inhibit the chemical reactions involved in stiffening the material.

A different theory, called the “precipitation theory,” suggests that the addition of sugar increases the concentrations of calcium, aluminum and iron in concrete. The sugar molecules combine with these metals to form insoluble chemical complexes that coat the cement grains. Several key chemical processes that harden the concrete are then impeded. Hydration slows down the process and the concrete takes longer to set. For this reason, sugar is known as a retarder. Retarders increase the setting time of concrete.

All sugars do not retard cement hydration equally. Refined white sugar is one of the best retarders. Lactose, the sugar found in milk, is a moderate retarder. Trehalose, a sugar produced by various fungi, is non-retarding and does not affect setting time.

Different theories and chemical processes are used to explain retardation for each type of sugar, and one or more mechanisms may be operating in the concrete. No one theory can explain the behaviour of all sugars in concrete under all conditions.

That all came from an article called "Sugar makes quicksand in the concrete jungle"
by Duy Cuong Nguyen.

I heard a story once of a place that was pouring pre-cast bridge sections in a yard somewhere. There were these brown spots in the set concrete that would not set and remained soft, able to be literally sthingyed out of the pour. After a thorough investigation of materials, drums, everything you could think of that went into the process of creating the concrete mix, a finisher was observed spitting chewing tobacco into the concrete, hence the brown spots. So there is enough sugar even in chewing tobacco spit to retard concrete. This was told to me by a very knowledgeable guy that was an admix supplier to the plant that I worked at.

[qctechie]

Mixing plain white sugar in concrete prevents the cement from joining with the water and slows the hardening of the minerals. Sugar-based solutions are sometimes added to the mixture when workers need to keep concrete moist like in paving a very large surface.

[LEAD DOG]

SUGAR CAUSES CAVITIES....silly