protection from the direct effects of precipitation on members must be 

 provided either by undercutting the ends to keep off wind-driven moisture or 

 by the use of fascia boards or end caps to prevent water from collecting on 

 vertical surfaces of the members. Ends of members should be coated with 

 white lead paste or treated with water-repellent sealer before the cap is 

 applied. Casein adhesives are not considered suitable for laminated members 

 intended for exterior use where the moisture content of the wood exceeds 16 

 percent for repeated or prolonged periods of service. 



2 Interior Use. Only one major condition must be satisfied 

 to ensure proper performance of casein adhesives in interior locations: the 

 moisture content of the wood must not exceed 16 percent for repeated or 

 prolonged periods of service. 



3 Performance Requirements. Dry-use adhesives shall 

 comply with the requirements of ASTM Standard D3024-72 for structural glued 

 laminated timber. 



(b) Wet-Use Adhesives . Phenol, resorcinol, and melamine base 

 adhesives will withstand the most severe conditions of exposure. They are 

 more expensive than water-resistant adhesives. Phenol-resorcinol base or 

 resorcinol base adhesives are the most widely used wet-use adhesives in 

 structural glued laminated members. 



1 Use. Although the wet-use adhesives may be employed for 

 all conditions of use, they are generally used only when the equilibrium 

 moisture content of the members in service exceeds 16 percent, such as the 

 following: 



(a) Members which must be pressure treated; 



(b) marine vessels and structures such as barges, ships, 

 piers, wharves, docks, slips, and dredge spuds; and 



(c) structures and members exposed to the weather, such 

 as bridges and bridge girders (other than for temporary 

 construction such as falsework and centering) . 



2 Performance Requirements . Wet-use adhesives shall 

 comply with the requirements of ASTM Standard D2559-72 for structural glued 

 laminated timber. Only adhesives meeting the requirement for wet use shall 

 be used with California redwood. 



10. Repair Materials and Methods . 



a. Adhesives. Adhesives are rarely used in field repairs. 



b. Concrete Encasements. Wood-bearing piles which have received 

 damage from marine borers (Fig. 72) (either partially or totally destroyed) 

 can be restored to their design capacity, in place, by encasing them in a 

 reinforced concrete jacket. Piles are enclosed with nylon jackets (adding 

 steel reinforcement as necessary) and the jacket is filled with a tremie 

 concrete. A similar successful method is to enclose the damaged part of the 

 pile with a fiberglass form, installing the necessary reinforcing and filling 

 the space between the form and the pile with a hydrophyllic epoxy (Fig. 73). 



268 



