Freeze/thaw durability of concrete with synthetic fibre additions

Concrete can be affected by freeze/thaw damage from the point of placing to being fully cured. The lack of available test data in the early life performance of concrete, with polypropylene fibre additions was a key factor justifying this research.This work examines the effects of freeze/thaw cycles starting at 5 days of curing where the concrete has reached about half of the design strength. The test methods used to evaluate durability were weight loss, final compressive strength and relative pulse velocity.A freeze/thaw test was carried to ASTM 666 B for 300 cycles and enhanced freeze/thaw protection was observed by the use of Type 1 polypropylene fibres in concrete when compared to plain and air entrained concrete.Fibres had the ability to entrain air and this is believed to be part of the reason for the demonstrated improvement in freeze/thaw durability.

► Four concrete types were tested, plain, air entrained and fibre at 0.9 kg/m3 and 1.8 kg/m3.
► Freeze/thaw protection is afforded with synthetic fibres
► Plain concrete provided little freeze/thaw resistance
► Post freeze/thaw durability factors for concrete with air/(76), 0.9 kg/m3 /(88), and 1.8 kg/m3 /(85)
► Concrete with 0.9 kg/m3 showed a superior performance using compressive strength and modulus.