Likewise, local conditions will affect how much concrete needs to be used for foundations, and so on. (insteading.com)
So Dr Sexton has overestimated the amount of concrete needed for each turbine by a factor of at least four and perhaps as much as twelve. (ramblingsdc.net)
You may not need to work on all of the following issues, but thinking about each area and how you measure up gives you concrete (myintimcity.com)