Thermal Cracking

[BigH]

Ron/Oldestguy/et.al.
Just wondering your thoughts on the following.

We have our designers worried about thermal cracking of low cement conventional concrete (LCVC). They have given us a maximum heat of hydration rise to no more than 40degC because of the fear of thermal cracking. Ambient temperature (year round) is between about 25 and 35 give or take. We are putting in a tunnel for access and they want reinforcing put around a tunnel we are putting into the dam cross section for access (very tight site) because their computations show thermal cracking with a 12 degC differential temperature.

Really??

 

[Ron]

Nope! I wouldn't expect thermal cracking at a 12degC differential unless the ambient was low.

We usually look at 1.4x to 1.6x ambient as the limiting max. internal concrete temperature.

 

[BigH]

Thanks Ron - didn't get back sooner as the little green star didn't show up. That's what we expect - so if ambient - low is 25, but normal is 28 to 30, say 42 to 45. Usually, I have seen 20degC rise. Thanks.