2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference


Title
Study of Precast Concrete Crazing Due to Moist Curing

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Author(s)
Mr. Lui Sammy Wong, Con Cast Pipe (Presenter)
Mr. James Cameron, Con Cast Pipe
Dr. Moncef Nehdi, Western University
Abstract

Precast concrete has been widely used around the world to accelerate the construction schedule. Better concrete quality is expected because fabrication is conducted under controlled environment. Accelerated curing method with high early cement adopted by many industry standards allows the precast manufacturer to maintain the factory efficiency without compromising the structural and durability performance. This paper reports on the surface crazing defects on the precast concrete products under four days moist curing. The crazing cracks has depth up to 2 mm deep resulted from the drying action from the fully saturated concrete product after extended moist curing period. A study was conducted understand the surface crazing defects on precast concrete made of self-consolidated concrete containing HE and GU cement. The effects of various curing regimes including air dry, immersion using portable water, water bath and burlap and various relative humidity during drying process after the concrete is removed from the moisture curing. The corresponding mechanical properties are also reported. The study concluded that the rate of drying and the type of cement impacts the final surface condition and contributes to the concrete crazing defect observed on the precast concrete product.