Development of Concrete Mixtures Containing Highly Reactive Pozzolans for Improved Durability in Florida Environments

摘要

The report describes research that evaluated the use of supplementary cementitious materials (SCM) to improve the service life of bridges constructed in severe marine environments. The SCM studied included ultra-fine fly ash, ground granulated blast furnace slag, silica fume, and metakaolin, in conjunction with fly ash. The plastic, mechanical, and durability properties of concrete made with these SCM were tested. Additionally, mixtures using these SCMs were optimized for use in the precast, prestressed piling for the Key Royale Drive Bridge Replacement Project. Thirteen trial mixtures were prepared using varying proportions of Portland cement, fly ash and selected SCM. One of the two control mixtures contained only Portland cement and the second contained 18% fly ash cement replacement by weight. The remaining eleven mixtures contained 18% fly ash with varying portions of SCM. Using results from laboratory testing, a decision matrix was created to select the mixture proportions that exhibited the best overall performance for each SCM tested. One mixture from each SCM was selected to be used in the production of piles for the Key Royale Drive Bridge Replacement Project. The decision matrix includes ratings for cost, mechanical properties, and durability.