The effect of freeze-thawing on steel fiber-matrix bond characteristics of cement based composites

Frost resistance is required for the concrete and reinforced concrete elements such as girder bridges, dams, concrete paving and airport runways in cold climatic zones. The water in the capillary pores of water-saturated concrete freezes and expands when subjected to frost effect. The expansion amount at the end of re-freezing cumulatively increases. If the stress caused by expansion exceeds the tensile strength of concrete, deterioration effects such as cracking, disintegration and spalling are occurred in concrete. In this study; fiber-matrix bond behavior of reactive powder concrete (RPC), normal concrete and mortar were studied with pull-out test method. Freeze-thaw effect on fiber-matrix bond was also investigated. The effect of maximum aggregate diameter, chemical admixtures, water/binder ratio, steel fiber and curing conditions on bond strength were determined. The fiber-matrix bond strength and mechanical properties of samples were compared after freeze-thaw cycles and the effect of freeze-thawing on bond behavior is investigated.