The IU Ferguson International building is an architectural, post-tensioned concrete structure. Irving Materials, Inc. (imi) collaborated with the architects, engineers, and the general contractor to design a performance based mix design to meet the expectations of the architectural and structural design team. Matching the adjacent limestone buildings was very important to the architects, owners and the community for this project. imi was able to create an acceptable color match using local materials. The final design avoided the originally specified specialty cement and aggregates making a significant impact on sustainability by providing excellent performance, improved strength, increased durability, reduced project costs and embodied carbon. imi Quality Teams performed over 40 trial batches to create the perfect design.
The final approved mix design reduced the total cementitious material by 13% and the total cement content by 32% of the original specified design. The project was also the first project in the area to utilize ASTM C595 - 1L cement adding to the learning curve for the imi team. 22% slag replacement and a strength enhancing admixture were used to substantially reduce the overall cementitious and still develop the early strength requirement of 3000 psi to stress tendons. The mix design also utilized a crystalline waterproofing admixture in the below grade walls and a shrinkage reducing admixture in the post tension slabs adding to the overall complexity.
All formwork joints, fasteners and tie holes had to be custom designed to be nonexistent in the final finish. The post-tension decks were constructed using two different mix designs that had to be placed simultaneously. The color and finish requirements required constant quality control presence to ensure the consistency of the mix. imi utilized new Smarthatch Technology in their ready-mix trucks as an additional tool to monitor consistency throughout the placements.
The decks were placed in below freezing conditions. The quality teams from imi and the general contractor followed the guidelines in ACI 306 Cold Weather Concreting. The general contractor provided heat under the decks and utilized wireless maturity sensors to ensure the post-tension tendons were stressed at the appropriate time. The deck placements used new e-ticketing technology to monitor the placement of two concrete mixtures simultaneously placed in the same deck using two pump trucks.