A problem not unique to the stadium. I'll repeat what my cement guy told me about pouring concrete it NEO..."There are two types of concrete outdoors in NEO, concrete that has cracked, and concrete that is going to crack" Henk Jonkers, of Delft University of Technology, in the Netherlands has created a concrete that heals itself. It's the world's most popular building material, and ever since the Romans built the pantheon from it some 2,000 years ago, we've been trying to find ways to make concrete more durable. No matter how carefully it is mixed or reinforced, all concrete eventually cracks, and under some conditions, those cracks can lead to collapse.