Based on what pics I have seen this am, the concrete was not the cause of this entire incident that is now being reported. The pictures I have seen the cracking and loss of concrete on one side of the valve only indicates to me a car passed over the slightly raised cover and caused the damage to the concrete with that impact with these three cars.
It may have simply been an unsecured or improperly secured iron valve cover, which might have been slightly lifted by some previous car, by under body suction and/or skid plate contact.
A screw up nevertheless.

Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.