Optimum Size Coarse Aggregate For Portland Cement Concrete Paving PDF Download

ODOT is continually searching for ways to improve the cost efficiency of Portland cement concrete without sacrificing concrete strength and stiffness. Because Portland cement is easily the most costly material used in normal concrete, limiting the amount of cement used is the quickest way to achieve cost effectiveness. In addition, limiting the cement content will also help to prevent dimensional instabilities in concrete such as shrinkage and creep. The use of larger sized coarse aggregates may be useful in limiting cement content, yet larger sized coarse aggregates may also decrease concrete strength by weakening the aggregate-cement paste bond. In many transportation structures, such as pavements, concrete strength is not critical, as dimensional stability, porosity, and durability play a more important role. It is possible, therefore, that larger sized coarse aggregates can reduce the cement content and improve these properties. Laboratory research is needed to determine if larger sized coarse aggregates can improve cement efficiency without reducing concrete strength.