Investigation of Alkali Silica Reactivity in North Carolina Highway Structures

摘要

Results of a two-year investigation of alkali silica reactivity in North Carolinabridges and pavements are described. Concrete cores from twenty-one facilities were examined. Tests included determination of alkali contents, residual expansion values, and mechanical properties, including dynamic modulus, compressive strength, and splitting tensile strength. In addition, petrographic examination and scanning electron microscopy with energy dispersive x-ray analysis, augmented as needed by x-ray diffraction, was also conducted. Cores were also examined for gel fluorescence with image analysis software after treatment with uranyl acetate. Expansion was found to be closely related to the area of fluorescing material. Mechanical properties were influenced by expansion, but not strongly.