Talking about Cement Retarder - was:The Apparition

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.Talking about all this cement retarder..............Namely Pozzalons etc..that nowadays are delivered in powder form to add to the cement mix.......
Many moons ago when I was with Liquid Cartage..(before it was taken over by Brambles and became Brambles Bulk Haulage..........
We used to deliver a retarder that went by the name of Pozzalith...only this was delivered in a liquid form.
All the batching plants had a liquid tank that we topped up and that was metered into the mix as required ..........
Now it appears every thing is in powder form...............
That is probably just another bit of useless information............................
..............................Billy...............................

Completely off topic n out-abounds
can remember mid 70'z
wen they building the upper thompson dam in Vic
we cartd a liquid nitrogen storage tank
n twas to add to the mixed concrete
for gotten twaz it to hasten the go n off of the concrete ot tuther way round



cya

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.$wishy......Twas probably to aid the curing process some how or other......................
My ole man worked on the Warragamba Dam, initially building the ice plant that
supplied cold water to the miles of piping that ran through the concrete wall purely,
(as I understand ) to slow the curing process, that made the concrete
more stable ...etc....etc...
Maybe the nitrogen was used as a cooling medium for the same purpose......????????
.........................Billy...........................

I knew a guy carted flyash (pozzolanic) for Transfield......the dust was destroying his eyesight.....he told Paul Vanco that he would have to quit cause he was going blind..........Vanco says "hey ,your eyes is already buggered,so you might as well keep going".....His eyes were always bright red and bloodshot from the ash.............bulk concrete has frozen water and ice added to cut down the heat of curing,which can boil the water and wreck concrete.

I saw a documentary for the hoover dam and they said when that was built they also had pipes running through the wall to run cold water through for the curing process. Cement gets hot when it cures.

Concrete cures very slowly in winter time, the concrete plants have 'Winter mixes' and 'Summer mixes' to assist the laying and curing process. So cooling the walls of the dams makes sense.

My late dad carted cement from Kandos to the Warragamba Dam during construction. He told us that if the powder was more than 24 hours old on delivery, it was regected. The mix was still hot when pored and the refrigerated water was piped through the wall to help cure the concrete.
Totally off topic, but I recently watched a doco on dam construction and they have discovered that concrete in major jobs does not cure totally for up to 100 years. Makes you wonder about some high rise buildings.
Steve.

Re: high - rise buildings: you would not think that concrete can deform much, but it does. Building will "shrink" vertically. A ten storey building will easily shrink an inch in the first ten years.

Jarrod.