Study On Freeze-Deicing Salt Scaling Resistance Of The Pavement Concrete In Cold Regions

Deicing salt was used to thaw snow on the concrete pavement in cold regions. It can lead to scaling and cracking of pavement so that cement concrete pavement did not reach service life to design. At present some measures adopted improved pavement concrete in freeze-water resistance but freeze-deicer salt resistance of pavement was not improved obviously. So the test method for freeze-deicing salt resistance of pavement concrete in cold regions was selected in this paper. Then the measures decreasing the scaled mass and relative dynamic modulus of elasticity loss factor were researched. Freeze-deicing salt resistance of pavement concrete was improved and the pavement concrete can be applied for cold regions.In this paper the domestic and foreign test methods for freeze-deicer resistance of concrete were compared. According to the kinds of heat transfer medium, contact style between concrete specimens and heat transfer medium, evaluation parameters and operation of test method, CDF method was selected to research freeze-deicing salt resistance of pavement concrete. And in accordance with the CDF method the test equips for freeze-deicer resistance were researched and developed. It had automatic control of temperature, automatic power-off protection and automatic data storage functions.Effect of the flexural strength, water cement ratio, admixture and air-entrained agent on freeze-deicer scaling resistance of pavement concrete was researched. The results showed the scaled mass and the loss rate of dynamic elasticity modulus decreased with increase of flexural strength. The freeze-deicer scaling resistance tended to improve with the reduction of water cement ratio. The scaled mass and the loss rate of dynamic elasticity modulus were decreased in the extent as result of admixture and air-entrained agent added into concrete. And freeze-deicer resistance of concrete with multiple kinds of admixture was superior to concrete with a kind of admixture so multiple admixtures should be advocated to use in practical engineering.WHY-100 automatic stress-testing machine was used for repeated loads and effect of repeated loads on freeze-deicer scaling resistance of pavement concrete was researched. The results showed that the scaled mass and relative dynamic modulus of elasticity loss factor increased with increase of load level after repeated loads, the freeze-deicing salt resistance of pavement decreased obviously.The effect of organosilicone on the compress strength, the scaled mass and loss rate of dynamic elasticity modulus of concrete were studied, the test surface of concrete specimens was observed. The results showed that the compress strength of ordinary concrete increased by 4.9% and the compress strength of high performance concrete was not changed at 28 day as result of organosilicone added into concrete. The scaled mass and loss rate of dynamic elasticity modulus of ordinary concrete and high performance concrete were greatly decreased. Organosilicone can decrease scaling on the surface, improve microstructure and freeze-deicer salt resistance of pavement concrete.In addition, the organosilicone coat prepared by our lab can obviously decrease the scaled mass and loss rate of dynamic elasticity modulus. Scaling on the surface of pavement concrete after deicer-frost was decreased. SEM observation showed that the microstructure of concrete was dense and there are few micro-cracks inside the concrete painted with the organosilicone. After drying no cubic NaCl crystals formed inside concrete. Compared with reducing the water and cement ratio and adding admixture and air-entrained agent the organosilicone painted on the surface of concrete was the more effective way to improve the freeze-deicing salt resistance of pavement concrete in cold regions.In this paper improvement of several measures in the freeze-deicing salt resistance of pavement concrete was appraised. The mechanics and technology way to improve the freeze-deicer scaling resistance of pavement concrete was summarized so it provided evidence for application and popularization of pavement concrete with freeze-deicer resistance.