Effect of Microcracking on Durability of High-Strength Concrete

Abstract

The relationship between cracking and chloride and water permeability of high-strength concrete (HSC) was studied. Two different mix designs were used: HSC_1 (w/b = 0.31) and HSC_2 (w/b = 0.25). The effects of crack width and sample thickness on permeability were examined. Cracks of designed widths were induced in the concrete specimens using the feedback-controlled splitting tensile test. Chloride permeability of the cracked samples was evaluated by using a rapid chloride permeability test. The water permeability of cracked concrete was then evaluated by a low-pressure water permeability test. Among the materials tested, only high-strength concrete with a very low water-to-cement ratio conductivity is sensitive with respect to cracking. The water permeability of cracked HSC significantly increases with increasing crack width. Among the parameters considered, crack parameters significantly affect water permeability, and there is little thickness effect. The results indicate that the water permeability is significantly more sensitive than conductivity with respect to the crack width used.