The Des Moines International Airport wanted to add another level to the already existing parking ramp.

Task

Add another level to the already existing parking ramp and not have it stick out like a sore thumb

Challenges

Norwalk Ready Mix was providing the concrete for the columns that would hold up the new level. Each column had an extensive amount of rebar in it so making the concrete flow was vital.We were matching appearance with old weather-worn precast. The finish was semi exposed aggregate so the contractor was faced with the challenge of finding a way to match it using different finishing techniques.

Solution

We started by making many different test panels with various aggregate proportions and concrete color pigment variations. We were supplying this job from our Norwalk plant which used a darker aggregate than what was needed to match up with the precast so we brought in much lighter aggregate from another source that proved to match up very well. We also provided onsite plasticizer addition to ensure that the flow of the concrete would fill every void the rebar was sure to make. By using plasticizer instead of water we were able to maintain strength. After the project engineer approved a mix from our samples, we help the contractor by delivering the sample to a sandblaster who would match the finish of the precast. The end result was a well-balanced look and a product that will serve the people of the DSM Airport for years to come.