Effect of water-cement ratio on fracture energy based on work of fracture

Abstract

Concrete is brittle material which generally consists of many micro cracks which are a potential source of crack propagation which leads to possible catastrophic failure and resulting fracture of concrete structures under service loads. The relationship of fracture energy to material properties has not been clearly identified, with most studies showing a relative insensitivity to the water-cement ratio, and concrete cracks propagate mainly along the aggregate-cement interface. This research is an experiment about the effect of water-cement ratio on fracture energy based on the RILEM method. The fracture energy is measured by testing under three bend points with the notch depth ratio is 0.25 and loading rate is 0.05 mm/sec using a closed-loop testing machine to produce load-displacement curve. Concrete used crushed stones with a maximum size of 19 mm which was tested at 56 days of age and has a water-cement ratio (w/cm) of 0.30, 0.40 and 0.6. The correlation between fracture energy and water-cement ratio are insensitive to each other. This can be seen when concrete containing a lower water-cement ratio (0.3) tends to have increased compressive strength but decreases fracture energy.