Cracking Control Technology for Concrete Using Urea
By H. Tanaka and T. Ayano
Concrete Journal Vol.52, No.4, Apr. 2014
- Synopsis
- Cracking of concrete structures not only affects the appearance of such structures but also lowers their performance, such as long-term durability and water tightness. To achieve durable concrete structures that are both strong and of good appearance, it is important to minimize the occurrence of cracks. Focusing on the high water solubility, non-volatility, and endothermic reaction of urea, the authors have developed technology that can reduce drying shrinkage-induced cracking through the inhibitory effect of the non-volatility of urea on moisture dissipation inside concrete, and also reduce thermal cracking through the endothermic reaction of urea, which reduces concrete temperature, as well as urea's hydration delaying effect, which reduces hydration heat during concrete production.
- Keywords:
- urea, drying shrinkage strain, endothermic reaction, temperature due to hydration, cracks, limestone aggregate
