508Silicone Sealed Joints

508.01 Description. This work shall consist of cleaning and sealing joints in accordance

with the plans and these specifications.

508.02 Materials. The silicone sealant material used in this construction shall meet the

requirements of Subsection 707.02.1.4. The backer rod shall meet the requirements of Subsection 707.02.1.5.

508.03 Construction Requirements.

508.03.1 Cleaning. Joints shall be clean, dry and fros t free when the sealant is applied.

Formed joints shall be thoroughly cleaned to remove all form release agents, curing compound residue, laitance, or any other foreign materials. All joints shall be thoroughly cleaned by sandblasting each face separately to the depth of the sealer and backer rod. The cleaning operation of existing joints shall ensure that the concrete joint surfaces which are to receive the new joint sealant and backer rod are free of all debris, discoloration and stain, as well as any and all other forms of contamin ation. If a clean exposed concrete surface cannot be obtained by sandblasting, the joints shall be refaced with a power driven concrete saw with diamond and/or abrasive blades. The refaced joints shall be washed and sandblasted as set forth above. Immediately prior to installation of the backer rod, the joints shall be cleaned with compressed air which is free of moisture and oil. Wiping fingers on cleaned surface of joints shall not s how evidence of dust. The joints shall be completely free of sand, oil and moisture. Material in expansion joints shall be removed to the required depth with a power saw and/or router in such a manner as not to damage the expansion material which is to remain in place.

508.03.2 Installing Backup Material. When shown as a requirement of the contract and

after the final cleaning, a resilient rod type backup material shall be installed with a positioning device to ensure conformity with the dimensions shown on the plans. The rod shall be compatible with the sealant and no bond or reaction shall occur between the rod and the sealant. Unless otherw ise designated, the rod diameter shall be one-eighth of an inch (1/8") greater than the joint width.

508.03.3 Installing Silicone Sealant. The installation of the sealant is to be performed

as soon after placing the backer rod as reasona bly possible to ensure that joints are still clean and dry. In the event a joint does be come contaminated, damp, or wet, the backer rod is to be removed and the joint cleaned and dried with a new backer rod reinstalled prior to placing the sealant. The ambient temperature at time of placement must be 40°F or higher. The sealant shall be applied by pumping only. The pump shall be of sufficient capacity to deliver the necessary volume of ma terial to completely fill the joint to the specified width and height of sealant in one pass. The nozzle shall be of sufficient size and shape to introduce the sealant inside the join t with sufficient pre ssure to prevent voids occurring in the sealant and force the sealant to make contact with the joint faces. This is especially critical in large joints. The sealant, if not of the self-leveling type, shall be tooled to provide the specified recess depth, thickness and shape as shown on the plans. Sufficient force or pressure shall be applied to the sealant in this tooling operation to force the sealant against the joint faces to ensure satisfactor y wetting and bonding. The sealant shall be placed to reasonably close conformity with dimensions and shape shown on the plans. Any unreasonable deviation will be cause for rej ection and necessary corrective action will be made by the Contractor.

508.03.4 Cleaning Pavement. After a joint has been sealed, all surplus sealant on the

pavement shall be promptly removed.

508.03.5 Opening to Traffic. Traffic shall not be permitted over the sealed joints until

the sealant is tack free.

508.04 Method of Measurement. Silicone sealed joints will be measured by the linear

foot.