Effect of Supplementary Cementitious Materials on the Performance of Concrete Pavement

Supplementary cementitious materials (SCMs) have been used in portland cement concrete pavements (PCCP) to increase their resistance to deterioration mechanisms, such as alkali-silica reaction (ASR), freeze and thaw, and permeability. In addition, SCMs are mostly by-products that can effectively reduce material cost and improve concrete sustainability. This paper presents the results of an experimental investigation carried out to evaluate the effect of Class C fly ash, Class F fly ash, and ground granulated blast furnace slag (GGBFS) on the performance of PCCP. Laboratory testing of multiple mixes with different combinations and percentages of SCMs is presented. This testing includes slump, unit weight, air content, time of setting, compressive strength, flexural strength, alkali-silica reactivity, freeze/thaw, length change, chloride ion penetration, and wet/dry test specified by Nebraska Department of Roads (NDOR). Field applications of four candidate mixes at two separate locations are also presented. Test results from laboratory and field investigations indicated that using a combination of Class C fly ash (15-20%) and Class F fly ash (20-25%), or all three SCMs in the range of 15-20% each, improves concrete durability and overall performance.