“Parametric Study of the Effects of Water to Cementitious Materials Ratio and Cementitious Materials Content on the Durability Properties of High Performance Concrete

This study takes a detailed look at the factors that affect the durability of concrete and how they can be applied to the development of a useful performance specification and help to extend the life of bridge decks and other concrete structures exposed to the elements of nature. A series of fifteen mixes (with varying cement contents and water/cement ratios) were performed in order to determine exactly which of these factors have a significant effect on the durability of a concrete mix. Controlling the water/cement ratio is necessary in order to control strength and permeability. Cement content was found to have little bearing on strength while the amount of cement affected the shrinkage significantly. Shrinkage is also dramatically affected by the amount of water in the mix. The results of the mixes were then used to develop a new specification for a bridge deck mix that will potentially improve the lifespan of bridge decks. Prescriptive versus performance specifications were also explored with the benefits and deficiencies of each form of specification looked at in detail.