Yesterday we had dinner at Hooters to celebrate my good friend's bachelor's party. Hooters, as we all know, is the great american sports restaurant well known for its chicken wings. I had a choice of medium, hot or 3-mile. I picked hot, since I figured this is Singapore, so hot should be pretty hot, for me at least. Turns out that hot is really only "mild" by my standards. Sheesh..... No kick at all! That got me wondering: why is the last category called 3-mile? It was only a few minutes ago that I recalled what 3-mile is. 3-mile island is the large nuclear reactor in North America, where there was some nuclear accident some years back. Ah, it must have been pretty hot in there!
That just gets me thinking about another chicken wing place, University Chicken in Santa Clara. University Chicken, also known as UC (not to be confused with the real UC) serves chicken wings coated in spicy habenero sauce. There are multiple grades of spicyness (10 i think?) with the hottest called "global thermonuclear". I tried the second hottest, thermonuclear, and it was so hot i couldnt get past the first one! Wonder how anybody can finish a plate of the hottest one....
Habenero just reminds me of the time when JM and Rory challenged me to finish that Habenero in the ASCE office. That just cracks me up! Ines totally freaked out man....
Saturday, August 27, 2005
flash set
Hmm. My friend says that flash setting could be the reason for the concrete not setting. Flash setting due to excessive gypsum that is. Something to consider....
Thursday, August 25, 2005
Concrete setting
I attended a course last week on contract management. The speaker started talking about concrete, which happens to be something I am quite passionate about (read the blog description). So Calcium Chloride is an accelerator while sugar is a retarder. And if you know your concrete, Calcium Chloride is not that good for concrete, because Chloride attack causes corrosion of steel rebar, and Calcium encourages alkali-silicate reaction (if you have reactive aggregate) which deteriorates your concrete in the long run.
So what's the point anyway? Well, the speaker, some expert, said that there was a lawsuit involving some contractor whose concrete could not set during construction. And after checking the site log, it appears that during casting it started raining and the workers ran away. So according to him it's the contractors fault cos anything could have fallen into the concrete, e.g. soft drinks with sugar, when they ran away, causing the concrete to not be able to set.
So what's the big deal anyway? Well firstly, if its just a couple of soft drinks, only a small area would not be able to set, not the whole slab. Secondly, sugar is a retarder, but unless u put a whole lot in, I think the concrete will still set if you just wait it out yah? I don't know the facts of the matter, but seems to me like the guy missed the point entirely. I don't think it was contaminants that caused the concrete not to set at all. In fact I think it's most likely a combination of poor concreting and mix proportioning that caused the concrete to HEAT UP too much during casting. I think what happened was "Delayed Ettringite Formation" also known ask "Internal Sulfate Attack" which occurs quite rarely because the concrete has to heat up till over 70 degrees celcius during casting. And yes, concrete can get that hot in Singapore, you'll be surprised. That's why we usually cast in the morning.
So, what's the point again? It just baffles me that the expert won the court case without having to actually find out the actual cause of the concrete not setting. He just pointed to the site log that the site was unattended. Which means there might have been some undesirable practices that were not discovered and corrected....
Interestingly enough, I wonder how many of you civil engineers out there even know what "Delayed Ettringite Formation" is? First time you heard of it? Even in a place where setting concrete can potentially reach 70 degrees celcius?
So what's the point anyway? Well, the speaker, some expert, said that there was a lawsuit involving some contractor whose concrete could not set during construction. And after checking the site log, it appears that during casting it started raining and the workers ran away. So according to him it's the contractors fault cos anything could have fallen into the concrete, e.g. soft drinks with sugar, when they ran away, causing the concrete to not be able to set.
So what's the big deal anyway? Well firstly, if its just a couple of soft drinks, only a small area would not be able to set, not the whole slab. Secondly, sugar is a retarder, but unless u put a whole lot in, I think the concrete will still set if you just wait it out yah? I don't know the facts of the matter, but seems to me like the guy missed the point entirely. I don't think it was contaminants that caused the concrete not to set at all. In fact I think it's most likely a combination of poor concreting and mix proportioning that caused the concrete to HEAT UP too much during casting. I think what happened was "Delayed Ettringite Formation" also known ask "Internal Sulfate Attack" which occurs quite rarely because the concrete has to heat up till over 70 degrees celcius during casting. And yes, concrete can get that hot in Singapore, you'll be surprised. That's why we usually cast in the morning.
So, what's the point again? It just baffles me that the expert won the court case without having to actually find out the actual cause of the concrete not setting. He just pointed to the site log that the site was unattended. Which means there might have been some undesirable practices that were not discovered and corrected....
Interestingly enough, I wonder how many of you civil engineers out there even know what "Delayed Ettringite Formation" is? First time you heard of it? Even in a place where setting concrete can potentially reach 70 degrees celcius?
It's the little things
It's the little things that we share
The sound of joy that's in the air
Children's laughter everywhere
and all our favorite things....
The sound of joy that's in the air
Children's laughter everywhere
and all our favorite things....
Wednesday, August 24, 2005
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