Exploratory investigation of high-performance fiber-reinforced cementitious composites for crack control

This study evaluated high-performance fiber-reinforced cementitious composites (HPFRCC), which are mortar mixtures with synthetic and steel fibers. The feasibility of using HPFRCC technology for transportation applications by the Virginia Department of Transportation, such as link-slabs that can replace joints on decks and in thin overlays for reduced permeability, was explored. HPFRCC has high ductility, is tough, and can exhibit strain-hardening that leads to multiple microcracks at large deformations. Such tight cracks prevent the transport of aggressive solutions and improve durability. In this study, mortar batches with high amounts of fly ash were prepared that had satisfactory compressive and flexural strengths, low permeability, and high ductility and toughness. The mixtures with special synthetic fibers exhibited strain-hardening with multiple microcracks. Shrinkage values were high but are not expected to cause distress because of the high tensile strain capacity. Mortar mixtures with fibers did not contain an air-entraining admixture; however, their resistance to cycles of freezing and thawing is expected to be satisfactory. The results obtained in a laboratory environment indicate that using HPFRCC in link (closure) slabs and thin overlays is possible. The study recommends that field applications be conducted to determine the full potential of this system in the field.