If you use new form materials for the mock-up, will all new form materials be required for each pour, or can the forms be reused? Constructing the mock-up with used forms is more realistic. Even if the mock-up is small, always use concrete from two truckloads to provide a batch-to-batch color variation in the approval process. If possible, include one truckload at the lowest slump and longest delivery time (3 inches and 112 hour) and one truckload at the highest slump and shortest delivery time (6 inches and 12 hour). Make sure to repair part of the mock-up and get repair procedures and materials approved prior to starting the project.
Finally, don’t take mock-up approval on a section by section basis. Sometimes architects or owners circle parts of the mock-up as acceptable and the rest is not. Get acceptance of the entire mock-up or build a new mock-up. If only parts of the mock-up are accepted, it’s likely that only parts of the finished structure will be accepted.
The contractor is first introduced to the specifier’s reality after mock-up approval: Specifications did not adequately describe what was wanted because the specifier was waiting for the mock-up results to decide what was wanted. That’s when the contractor realizes there isn’t enough money in the bid to duplicate the specifier’s desired mock-up results for the structure. Even if the specifier’s desires were not described in the project specifications, however, acceptance of a request for a change order is unlikely. Too many specifiers, and owners, take advantage of a fixed-price contract after mock-up approval to increase the value-added.
Building a nearly flawless mock-up, but with efforts that are impractical for consistent replication in a production situation, just gives the owner, architect or engineer a bigger stick to beat you with during mock-up approval and final acceptance. That’s the foul up.