what caused the damage in the first place. The damage may be the result of 

 poor design, faulty workmanship, mechanical abrasive action, cavitation or 

 erosion from hydraulic action, leaching, chemical attack, chemical reaction 

 inherent in the concrete mixture, exposure to deicing agents, corrosion of 

 embedded metal, or other lengthy exposure to an unfavorable environment. 

 Figures 18 and 19 show damage from various sources. 



Whatever may have been the cause, it is essential to establish the 

 extent of the damage, and determine if the major part of the structure is 

 of suitable quality on which to build a sound repair. Based on this 

 information, the type and the extent of the repair are chosen. This is the 

 most difficult step, one which requires a thorough knowledge of the subject 

 and mature judgment by the engineer. If the damage is the result of 

 moderate exposure of what was an inferior concrete in the first place, then 

 replacement by good quality concrete should ensure lasting results. On 

 the other hand, if good quality concrete was destroyed, the problem becomes 

 more complex. In that case, a very superior quality of concrete is required, 

 or the exposure conditions must be altered. 



Figure 18. Piles damaged by corrosion of steel reinforcement 

 (photo courtesy of Los Angeles Harbor Department). 



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