Improving the Long-Term Performance of Bridge Decks using Deck and Crack Sealers
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Many bridges are exposed to snow and ice during the winter. As snow and ice accumulate over the bridge’s concrete deck, deicing salts are usually spread on the bridge deck to remove and dissolve the snow and ice. Deicing salts form a chloride solution that penetrate through the concrete and cause corrosion in reinforcing steel and deterioration in concrete. In order to decrease the chloride ingress into the concrete, sealers are applied over the concrete deck surface. It is critical to extend the life of the concrete bridge deck as deck replacement is very time consuming and expensive. The primary objective of this project was to develop a guide for using deck and crack sealers. In this research, five deck sealers and six crack sealers were applied on two different type of concrete that are commonly used in Northern Nevada: American Ready-Mix and 3D Ready-Mix. The effectiveness and performance of commercially available deck and crack sealers were assessed by laboratory tests. The sealers were chosen according to criteria that are discussed in this report. Five deck sealers were subjected to three laboratory tests that were conducted at the University of Nevada, Reno (UNR), and a freeze/thaw test conducted in a company in Denver, Colorado. The specimens subjected to the freeze/thaw test were then sent back to UNR to complete testing. Six crack sealers underwent two laboratory tests conducted at UNR. All the tests were conducted according to ASTM, AASHTO, and NCHRP reports standards. In order to report the effect of the sealers, a comparison was made between specimens covered with sealers and control specimens (i.e. specimens without any sealers). Also, a comparison was made between all the sealers together, and the sealers were assigned into different categories according to their performance. Each category has a certain score according to the test, and a total score for each sealer was calculated for all the tests. A recommendation is given for the sealers that gave the highest performance. The recommendation was not given for a certain sealer only, but for the chemical family and general properties for these sealers that gave the highest performance. Generally, all the deck sealers were effective in reducing the amount of chlorides ingress into the concrete. Silane sealers gave higher performance than siloxanes sealers, and water-based sealers gave a higher performance than solvent based sealers. Sealers with chemical family of Alkylalkoxy Silane gave higher performance among all the other sealers, and it is recommended to use sealer of Alkylalkoxy Silane and water-based sealer. Epoxies sealers provided higher performance for bond strength than methacrylate sealers. While for depth of penetration, methacrylate sealers could penetrate deeper into cracks because their viscosity is lower than the epoxies.
Report No. CCEER-18-02