(2) unanticipated service conditions have resulted in 

 greater joint movements than those allowed for when the joint 

 design and type of sealant were determined; 



(3) the wrong type of sealant for the particular conditions 

 was selected, often on the false grounds of economy in first 

 cost; 



(4) new sealants have sometimes been initially overpromoted 

 and used before their limitations were realized; and 



(5) poor workmanship occurred when constructing the joint, in 

 preparing it to receive the sealant, or during sealant installa- 

 tion. 



At joints minor touchup of small gaps and soft or hard spots in 

 field-molded sealants can usually be made with the same sealant. However, 

 where the failure is extensive it is usually necessary to remove the 

 sealant and replace it. 



Where the sealant has generally failed but has not come out of the 

 sealing groove it can be removed by hand tools or, on larger projects such 

 as pavements, by routing or plowing with suitable tools. Where widening is 

 required to improve the shape factor, the sealant reservoir can be enlarged 

 by sawing. 



After proper preparation to ensure clean joint faces and additional 

 measures designed to improve sealant performance such as the improvement of 

 shape factor, provision of backup material, and possible selection of a 

 better type of sealant, the joint may be resealed. 



Minor edge spalls to concrete joint faces may be repaired with an epoxy 

 resin mortar, an essential operation if a compression seal is being used. 

 Otherwise most repairs to correct defects in the original construction of 

 the joint involve major, exacting, and often expensive work. The reason 

 for the failure must be identified and, depending on the cause, continuity 

 must be restored in the joint system either by the removal of whatever is 

 blocking the free working of the joint or by cutting out the whole joint 

 and rebuilding it. 



Where cracks have taken over from a nonworking or absent joint, these 

 can be routed out and sealed with a suitable field-molded sealant to 

 prevent damage to the structure. The selection of a suitable sealant and 

 installation method follow those for the equivalent joint. An additional 

 problem occurs where water is flowing through the crack and the upstream 

 face cannot be reached for sealing. Before sealing can be successfully 

 undertaken, the waterflow must be stopped. If the source of water cannot 

 be cut off by dewatering, then (depending on the circumstances) one of the 

 many alternatives such as cutting back the crack deeper and plugging with 

 a quick-setting or dry-pack mortar, or cement, chemical or epoxy resin 

 grouting may be tried. Successful execution of any of these operations 

 usually requires specialized knowledge, experience, and workmanship. 



37 



