for Highway Construction Page 709 of 715 SECTION 719-RESERVED for Highway Construction Page 710 of 71 5 SECTION 720 – MISCELLANEOUS
720.01 Water for Concrete, Grout, and Mortar .
The Contractor may use water from municipal drinking water supplies for concrete, grout , or mortar . The Contractor may use water from other sources, provided it is reasonably clear without oil, contains less than 1,000 parts per million of chlorides and less than 1,000 parts per million of sulfates in accordance with ASTM C1602. If a water source other than a municipal drinking water supply is proposed, submit independent laboratory test reports verifying compliance with these chemical requirements. Submit reports that are less than 2 years old before using a nonmunici pal drinking water supply.
720.02 Elastomeric Bearings .
1.Description. Elastomeric bearings include unreinforced pads, consisting of elastomer only, and reinforced bearings with steel laminates. The Engineer will not allow st acking of individually -laminated pads. Provide bearings with the dimensions, material properties, elastomer grade, and type of laminates specified. Show the design load specified and testing requirements. Provide Grade 3 bearings with a shear modulus of 0.130 ksi, steel reinforced, and subjected to the load- testing requirements.
2.Materials. The raw elastomer consists of virgin neoprene (polychloroprene) or virgin natural rubber (polyisoprene). Provide the elastomer compound classified as being of low -temperature Grade 0, 2, 3, 4, or 5. The grades and other material properties are defined in the AASHTO LRFD Bridge Design Specifications Section 14 and AASHTO M 251. A higher grade of elastomer may be substituted for a lower one.
3.Fabrication. Fabricate bearings in accordance with AASHTO M 251.
4.Testing. Subject materials for elastomeric bearings and the finished bearings to the tests described in AASHTO M 251 Section 8.9.2.
5.Installation. The Contractor may place elastomeric bearings without external load plates directly on a concrete or steel surface, provided that it is flat within a tolerance of 0.005 of the nominal dimension for steel reinforced bearings and 0.01 of the nominal dimension for others. Place bearings on surfaces that are horizontal to within 0.01 radian. Correct the lack of parallelism between the top of the bearing and the underside of the girder that exceeds 0.01 radian by grouting or as directed. Do not weld exterior plates of the bearing, unless at least 1.5 inches of the steel exists between the weld and the elastomer. Do not allow the elastomer or the bond to be subjected to temperature higher than 400°F.
720.03 PTFE Bridge Bearing Pads .
Provide PTFE pads and stainless steel mating surface where specified that meet A ASHTO Specifications for Highway Bridges. If filled PTFE sheet is used, only glass -fiber filler will be approved.
720.04 Epoxy -Resin -Base Bonding Systems for Concrete .
Meet ASTM C881 with the classification (type and grade) of the system selected as specified. The Contractor and the Contractor’s supplier, with approval, will determine the class after work conditi ons have been
Source: Idaho Standard Specifications for Highway Construction, 2023 Edition. Pages 745–745 of 768.