The concrete under evaluation includes the concrete steps and the intermediate
landing at the entrance of the main building in Chaska, MN. The building is the
headquarters of a pharmaceutical manufacturer company.
Concrete was placed on December 1, 1989 and the building was occupied in
August 1990. Signs of concrete deterioration, including pop outs, scaling and steps breaking
off, were first observed in the spring of 1991. The concrete surface received three
toppings over a period of five to six years and all toppings failed.
The building owner requested Jaber Engineering Consulting, Inc. to investigate the
deterioration of the concrete steps and landing, find the cause of failure and provide a
remedy for the situation.
JEC performed forensic engineering and was able
to find the cause of the concrete failure and the failure of the subsequent toppings. The
main reason for the deterioration was the lack of durability of the original concrete.
JEC recommended a repair solution which is to remove all toppings and the original
concrete and to replace it with new durable concrete.
The owner requested JEC to perform field
observation to monitor compliance of repair work to the repair recommendations