Early this morning, I headed out to the final bridge deck pour on one of our projects. The pour started at 2am and when I arrived at 4 am, the crews were almost half way done with the deck. It's an amazing process to watch as the rough, rocky mess of concrete is turnedinto a smooth deck by the screed (smoothing/leveling machine) and the hand work done behind the machine. Now I'm a geek for construction so it was definitely worth getting up really early and spending two hours watching our very skilled crews create a beautiful product.
Now why did the pour have to happen in
the middle of the night? By state specification which considers the integrity of the bridge, the concrete cannot have a temperature of more than 85 degrees. In order to obtain a lower temperature, the pour is conducted at night and ice is added to the concrete. Last night, the air temperature was 82 (yes, at 4 am) and the concrete hovered between 81-83 degrees. The state provides contractors with a computer program to determine proper pouring conditions. It's a very helpful tool that helps guarantee proper concrete hardening and limits potential structural problems.
Once the pour is complete, the crews place evaporation retardant on the deck, cover the deck with blankets to assist in moisture retention, and call it a day. Over the next 10 days, the deck will be carefully taken care of to ensure proper hardening and then saw cut to put the required grooves on the deck. The next steps include pouring sidewalks and railings, removing wood forms, and finishing the approaches. Within the next few months, it'll be open to full traffic and our work will be complete.
After a few hours observing the process, I thanked our concrete manager for the informational session on the pour and headed off to find a little breakfast.
Until then, happy travels and many laughs...